Academic literature on the topic 'Measles vaccinated case'

Objectives: To evaluate the clinical profile and case fatality rate and their comparison in relation with vaccination status in admitted children. Study Design: Case series retrospective study. Setting: Pediatric units of the tertiary care Hospitals (Bahawal Victoria Hospital and the Civil Hospital) affiliated with Quaid-e-Azam medical College Bahawalpur situated in Southern Punjab, Pakistan). Period: 01/01/2013 to 06/9/2013. Methods and Material: A clinical diagnosis of measles (as made by consultants of said Pediatric units) and residing in Bahawalpur district for more than one month of period before admitting in the hospital was included and reviewed. The help of Statistical department of Executive District Officer Health Bahawalpur was taken for missing information as the measles is notifiable disease and all cases were notified to Executive District Officer Health. The children who were nonresident of Bahawalpur District or with incomplete data were excluded. The children were divided into three groups depending on number of measles vaccine doses given. Results: The data of 557 children admitting during the period 01/01/2013 to 06/9/2013 with a clinical diagnosis of measles and resident of Bahawalpur district was included. 52.97% were males. 26.57% were unvaccinated and 73.43% vaccinated (39.14% with one dose and 34.29% with two doses). The mean age ± SD in unvaccinated children was 24.68±27.04, with one dose vaccination 50.94 ±35.58 and with two doses vaccination was 45.05 ±23.67 months. The case fatality rate was 2.87%. The case fatality was significantly higher in males vaccinated with two doses of vaccine as compared to either ones vaccinated with one dose or unvaccinated ones but this difference was not found in females. Conclusion: This study shows that there is urgent need of proper surveillance of measles cases.

Корь высококонтагиозное, острое вирусное заболевание, которое может привести к та- ким осложнениям, как пневмония, энцефалит, вплоть до летального исхода. В результате вы- сокого охвата 2-дозной вакцинацией против кори в нашем регионе сохраняется относитель- но благоприятная эпидемиологическая ситуация. Регистрация кори в Республике Беларусь связана с завозными случаями из других стран, где корь остается эндемичной. Не исключены в данной ситуации и случаи возникновения кори у иммунизированных пациентов. В статье представлен клинический случай заболевания корью у вакцинированного пациента. Measles is a highly contagious, acute viral illness that can lead to complications such as pneumonia, encephalitis, and death. As a result of high 2-dose measles vaccination coverage in the Belarus and the high control of measles in our region, a relatively favorable measles situation remains. Nevertheless, the import of cases from other countries where measles remains endemic continues to occur, which leads to the emergence of groups of cases in Belarus. Cases of measles, even in vaccinated patients, are not excluded in this situation. The article presents a clinical case of measles in a vaccinated patient.

SummaryDuring a large measles outbreak in Quebec City in 1989, two investigations conducted in parallel evaluated the relative risk of measles and measles vaccine effectiveness with respect to age at vaccination. The study was a school-based case-control study including 563 cases and 1126 classmate controls. The second was a cohort study of the siblings of school cases including 493 siblings aged between 1 and 19 years. The relative risks (RR) of measles were similar in both settings and the trend towards increased vaccine efficacy with increasing age at vaccination was highly significant (P < 0·001). Vaccine efficacy rose from 85% in children vaccinated at 12 months of age to ≥ 94% in those vaccinated at 15 months and older. Even for children vaccinated at or after 18 months of age. the RR of measles was reduced when compared with children vaccinated between 15 and 17 months of age (RR 0·61. CI 95% 0·33–1·15). Small changes in the timing of initial measles vaccination can have a major impact on vaccine efficacy.

Objective: To determine the status of vaccination among confirmed measles cases and to determine the association of vaccination status with the occurrence of measles infection. Methods: A cross-sectional survey was carried out in the province of Sindh from January 2016 to April 2016. The study included patients of both gender, ³9 months of age, fulfilling the case definition of measles by World Health Organization (WHO), who were reported to and/or picked by the measles surveillance officers. A sample of 3-5 ml of blood was collected from each registered patient between day 4 and day 28 of the rash to test for measles IgM antibodies. The samples were labelled and sent to National Measles Laboratory, National Institute of Health (NIH) Islamabad in reverse cold chain. Patients who tested positive for IgM antibodies were grouped as confirmed measles while patients negative for measles IgM antibodies were grouped as suspected measles. Data of both the groups was analysed using windows SPSS 21 for vaccination status, for frequency of measles infection against the number of doses of measles vaccine received. Frequencies of vaccination among confirmed measles cases were compared with suspected measles for statistical significance using Chi-square. P-value of <0.05 was taken as significant. Results: A total of 572 out of 915 study subjects were confirmed measles cases, of which 258 (45%)were never vaccinated against the disease as compared to 72 (12.6%) who were completely vaccinated. Overall, 128 (37.3%) were fully vaccinated amongst suspected measles. Vaccination sta- tus was not known in a quarter of patients in both groups. A significant association was found be- tween the vaccination status and measles infection with higher frequency of measles in unvaccinated as compared to the vaccinated (p<0.001). Conclusion: We conclude that the vaccination rate among measles patients was significantly lower than among non-measles patients. A sizable 12.6% got the disease in spite of completing measles vaccination.

The MMR vaccination program was introduced in Spain in 1981. Consistently high vaccination coverage has led to Spain being declared free of endemic measles transmission since 2014. A few imported and import-related cases were reported during the post-elimination phase (2014 to 2020), with very low incidence: three cases per million of inhabitants a year, 70% in adults. In the post-elimination phase an increasing proportion of measles appeared in two-dose vaccinated individuals (up to 14%), posing a challenge to surveillance and laboratory investigations. Severity and clinical presentation were milder among the vaccinated. The IgM response varied and the viral load decreased, making the virus more difficult to detect. A valid set of samples (serum, urine and throat swab) is strongly recommended for accurate case classification. One third of measles in fully vaccinated people was contracted in healthcare settings, mainly in doctors and nurses, consistent with the important role of high intensity exposure in measles breakthrough cases. Surveillance protocols and laboratory algorithms should be adapted in advanced elimination settings. Reinforcing the immunity of people working in high exposure environments, such as healthcare settings, and implementing additional infection control measures, such as masking and social distancing, are becoming crucial for the global aim of measles eradication.

Background: In 2019, a measles community outbreak resulted in a secondary case in a health care worker (HCW) working in a pediatric hospital in Montral, Canada. Following the event, HCWs were screened to identify individuals susceptible to measles infection based on serology results. Objective: Our aim was to assess measles seroprotection rates and to evaluate vaccine responses of susceptible HCWs using commercial enzyme immunoassay (EIA) or enzyme linked immunosorbent assay (ELISA). Methods: Emergency department (ED) employees, including doctors, were screened for measles susceptibility as part of a postoutbreak measure by the hospital occupational health service. Demographic information was collected. Measles history and vaccination information were collected using a personal vaccination booklet, employee vaccination profile, or the Qubec vaccination registry. According to the Quebec Immunization Protocol (PIQ), individuals born before 1970, or who have received 2 doses of a measles-containing vaccines are considered protected. Individuals with undetectable or equivocal antibody levels were considered at risk of measles infection. These individuals were offered vaccination and were tested for vaccine response 4 weeks after vaccination. Results: Anti-IgG measles antibody results, demographic information, and vaccination information were obtained for 257 employees. The results are currently available for 233 HCWs: 224 HCWs (96%) were seropositive, 7 (3%) were seronegative, and 2 were equivocal. Among seronegative individuals, 6 (85.7%) were born after 1980 and 3 (42.9%) had received 2 doses of a measles-containing vaccine. Of those with an equivocal result, 1 (50%) had received 2 doses and 1 (50%), born after 1970, did not confirm vaccination status. Finally, 9 (4%) of seropositive individuals were not vaccinated; of whom 8 (88.9%) were born before 1970. Conclusions: Our preliminary results suggest that the 95% immunity threshold that is usually required to prevent secondary transmission of measles has been reached in our ED HCW cohort. Even years after the second MMR dose, HCWs remain well protected. Relying on documented vaccination status is thus acceptable.Funding: NoneDisclosures: None

Abstract Objective Preventive measures in the setting of a suspected measles case in a hospital setting are important to stop the secondary spread. In this report, we evaluated the prevention attempts after two suspected cases of measles were reported in a pediatric clinic. Methods We evaluated prevention interventions including isolation, intravenous immunoglobulin, or measles–mumps–rubella (MMR) vaccine after two patients were diagnosed with maculopapular rash compatible with measles in the pediatric clinic. Results There were 50 patients (29 were outpatients, 21 were inpatients), 19 health care personnel (HCP), and 50 caregivers who were in contact with index cases. All of the HCP and 40 of the caregivers were immune to measles. Additional dose of MMR vaccine was recommended to five of the outpatients by phone. A total of 12 patients who were being followed up as inpatients (8 patients aged 6–12 months, 4 patients aged ≥ 12 months) were vaccinated with one dose of MMR vaccine. Only a 12-year-old male patient was admitted due to complaints suggesting measles after 14 days from discharge. It was learned that he had received a single dose of vaccine before so he was recommended an additional dose of MMR vaccine by the phone, but he did not go to the health institution on the day of the call. Conclusion Postexposure prophylaxis is effective to prevent measles transmission. Although young infants have the highest risk for transmission of measles in a health care–associated outbreak, adolescents and older children who are single vaccinated also have high risk for clinical measles.

ABSTRACTIn the United States, approximately 9% of the measles cases reported from 2012 to 2014 occurred in vaccinated individuals. Laboratory confirmation of measles in vaccinated individuals is challenging since IgM assays can give inconclusive results. Although a positive reverse transcription (RT)-PCR assay result from an appropriately timed specimen can provide confirmation, negative results may not rule out a highly suspicious case. Detection of high-avidity measles IgG in serum samples provides laboratory evidence of a past immunologic response to measles from natural infection or immunization. High concentrations of measles neutralizing antibody have been observed by plaque reduction neutralization (PRN) assays among confirmed measles cases with high-avidity IgG, referred to here as reinfection cases (RICs). In this study, we evaluated the utility of measuring levels of measles neutralizing antibody to distinguish RICs from noncases by receiver operating characteristic curve analysis. Single and paired serum samples with high-avidity measles IgG from suspected measles cases submitted to the CDC for routine surveillance were used for the analysis. The RICs were confirmed by a 4-fold rise in PRN titer or by RT-quantitative PCR (RT-qPCR) assay, while the noncases were negative by both assays. Discrimination accuracy was high with serum samples collected ≥3 days after rash onset (area under the curve, 0.953; 95% confidence interval [CI], 0.854 to 0.993). Measles neutralizing antibody concentrations of ≥40,000 mIU/ml identified RICs with 90% sensitivity (95% CI, 74 to 98%) and 100% specificity (95% CI, 82 to 100%). Therefore, when serological or RT-qPCR results are unavailable or inconclusive, suspected measles cases with high-avidity measles IgG can be confirmed as RICs by measles neutralizing antibody concentrations of ≥40,000 mIU/ml.

An outbreak of measles occurred in a municipal school system which had reported 98% of students immunized against measles. A case-control study was conducted to determine reasons for vaccine failure Vaccine failure was associated with immunizations that could not be documented in the provider's records. Among children with provider-documented immunization, vaccine failure was associated with vaccination at 12 to 14 months of age with an odds ratio of 4.73. Among children vaccinated at 15 months or older, vaccine failure was not associated with time elapsed since vaccination. Studies should be conducted to determine whether unreliable immunization records are a more widespread problem. Further consideration should be given to routine revaccination of children previously vaccinated at 12 to 14 months of age.

Abstract Background Although pediatric travelers comprise < 10% of US international travelers, they account for almost half of all measles importations among returning travelers. For travelers 1–18 years with no other evidence of measles immunity, the Advisory Committee on Immunization Practices (ACIP) recommends 2 MMR vaccine doses before departure; 1 dose is recommended for infant travelers (6 to <12 months) and does not count toward their primary immunization series. All US travelers (6 months to < 6 years) are at risk for being undervaccinated for measles because MMR is routinely given at 1 years and 4–6 years. Methods We developed a decision tree model to evaluate the clinical impact and cost per case averted of pretravel health encounters (PHE) that vaccinate MMR-eligible pediatric international travelers. We compared 2 strategies for infant (6 to < 12 months) and preschool-aged (1 to <6 years) travelers: (1) no PHE: travelers departed with baseline MMR vaccination status vs. (2) PHE: MMR-eligible travelers were offered vaccination. All simulated travelers experienced a destination-specific risk of measles exposure during travel (mean, 237exposures/10M travelers; range, 19–6,750 exposures/10M travelers); if exposed to measles, travelers were at risk of illness stratified by age and MMR vaccination status (range, 0.03–0.90). Costs include direct medical costs and lost work wages for guardians. Model outcomes included measles cases, costs, and cost per case averted. We varied inputs in sensitivity analyses. Results Compared with no PHE, PHE averted 451 measles cases at $985,000/case averted for infant travelers and 54 measles cases at $1.5 million/case averted for preschool-aged travelers (table, bottom). PHE can be cost-saving for travelers to regions with higher risk of measles exposure and if more MMR-eligible travelers are vaccinated at PHE (Figure 1). At a risk of exposure associated with European travel, PHE had better value when a measles importation led to a higher number of contacts or more US-acquired cases per importation (Figure 2). Conclusion PHE for pediatric travelers (6 months to <6 years) decreased the number of imported measles cases and saved costs, especially if targeted to travelers with higher-risk destinations, if more MMR-eligible travelers are vaccinated at PHE, or if outbreaks are larger. Disclosures All authors: No reported disclosures.

INTRODUZIONE. Il morbillo è una malattia esantematica estremamente contagiosa trasmissibile per via aerea causata da un virus della famiglia Paramyxoviridae, genere Morbillivirus. L’infezione spesso è causa di complicanze severe e decessi, è prevenibile con la vaccinazione e presenta i requisiti per l’eliminazione. L’Italia fa parte dei 12 paesi europei dove la trasmissione del morbillo è ancora endemica. Il Global Measles and Rubella Strategic Plan 2012 – 2020 ha fissato il goal di eliminazione del morbillo endemico nella Regione Europea dell’OMS. Per raggiungere tale obiettivo è necessario ottenere e mantenere coperture vaccinali elevate (>95%) e disporre di un sistema di sorveglianza sensibile e di qualità. La sorveglianza molecolare del morbillo è una componente chiave della verifica dell'eliminazione del morbillo endemico ed è uno strumento cruciale sia per stabilire eventuali link epidemiologici tra casi che si verificano nello stesso periodo in una determinata area geografica sia per identificare le possibili fonti di importazione. Con il progredire del programma di eliminazione, la diversità genetica dei ceppi di morbillo circolanti diminuisce. I continui viaggi aerei e la facilità di scambi tra i paesi favoriscono le importazioni in una determinata area geografica di varianti virali appartenenti allo stesso genotipo. In questo contesto, i tradizionali metodi di laboratorio non consentono di distinguere la trasmissione endemica da eventi di importazione delle stesse varianti virali. Con il progredire del programma di vaccinazione, inoltre, una quota sempre più alta di casi di morbillo si verifica in soggetti vaccinati. Le nuove e avanzate tecnologie devono quindi permette di ampliare le conoscenze su questi aspetti e consentire di identificare ceppi potenzialmente in grado di eludere la risposta immunitaria. SCOPO. Scopo del presente progetto di dottorato è quello di studiare e sorvegliare nel tempo l’epidemiologia molecolare del morbillo in vista dell’obiettivo di eliminazione, attraverso lo sviluppo e l’utilizzo di metodologie innovative molecolari e bioinformatiche. La ricerca pertanto si propone di combinare il metodo epidemiologico tradizionale con le tecniche molecolari e bioinformatiche che la nuova era offre. Un ulteriore obiettivo è stato quello di studiare casi confermati di morbillo in soggetti precedentemente vaccinati, al fine di valutare il fallimento vaccinale e identificare eventuali mutanti escape a livello del gene H. MATERIALI E METODI. Sono stati analizzati i campioni biologici provenienti da pazienti con diagnosi sospetta di morbillo raccolti nell’ambito della Sistema di Sorveglianza Integrata Morbillo e Rosolia della Regione Lombardia (rete MoRoNET), da marzo 2017 a luglio 2019. I campioni sono stati sottoposti a estrazione dell'RNA e a test di Real Time RT-PCR per l’identificazione del genoma del virus del morbillo. Tutti i campioni risultati positivi sono stati sottoposti a retrotrascrizione e a successiva amplificazione genica della regione N-450 del virus del morbillo mediante nested RT-PCR per la caratterizzazione genotipica. Campioni di interesse (N=50) sono stati sottoposti ad amplificazione del gene virale H mediante due emi-nested PCR e ad amplificazione dell’intero genoma attraverso l’utilizzo di specifiche coppie di primer per l’amplificazione di 10 frammenti parzialmente sovrapposti. Gli amplificati sono stati sequenziati e sono state analizzate filogeneticamente le sequenze N-450, N-450/H e l’intero genoma attraverso diversi programmi bioinformatici (ClustalX2, BioEdit, MEGA7) per le valutazioni filogenetiche. Lo studio dei casi vaccinati è stato condotto attraverso l’analisi dei dati sierologici ottenuti dal database del laboratorio di riferimento regionale; in aggiunta, è stata analizzata la sequenza amminoacidica (ottenuta tramite la conversione delle sequenze nucleotidiche grazie al programma BioEdit) della proteina H di 7 casi vaccinati e di 80 casi non vaccinati come gruppo controllo. I dati anagrafici, clinici ed epidemiologici relativi ai casi di morbillo analizzati nel presente lavoro sono stati ottenuti dal database della Regione Lombardia per le malattie infettive MAINF. RISULTATI. Complessivamente, tra marzo 2017 e luglio 2019 sono stati indagati 885 casi sospetti di morbillo segnalati a Milano e nelle aree limitrofe. Il 74.2% dei casi indagati è stato confermato in laboratorio. Il maggior numero di casi è stato confermato nel 2017 (50.4%). Le fasce d’età più colpite sono state quelle dei giovani tra i 15 e i 39 anni (63.0%) e degli adulti over-39 anni (21.5%), dato che si è confermato per tutti e tre gli anni esaminati. Il 92.1% dei casi confermati di morbillo non era vaccinato. La consultazione del database regionale MAINF ha permesso di classificare i casi confermati come sporadici (57.4%) o appartenenti a focolai (42.7%). Il 9.7% dei casi confermati dal nostro laboratorio si trovava fuori dal territorio in esame durante il periodo di incubazione della malattia. In questo modo è stato possibile definire l’importazione dell’infezione, sia dall’estero (44.3% dei casi importati) che da altre regioni italiane (55.7% dei casi importati). La caratterizzazione genotipica mediante sequenziamento della regione N-450 di Morbillivirus è stata completata con successo per il 95.3% dei casi. È stato possibile evidenziare la costante co-circolazione di due genotipi, il D8 (72.9%) e il B3 (26.1%). L’analisi intra-genotipica ha permesso di identificare complessivamente 16 varianti virali, di cui 8 già classificate dall’OMS e definite WHO named strain. In particolare, sono state identificate 5 WHO named strain D8 (Mv/Osaka.JPN/29.15, Mvs/London.GBR/21.16/2, MVi/Hulu-Langat.MYS/26.11, MVs/Gir-Somnath.IND/42.16, Mvs/Victoria.AUS/6.18) e 3 WHO named strain B3 (MV/Dublin.IRL/8.16, MVs/Saint-Denis.FRA/36.17, Mvs/Ljubljana.SVN.27.17). La D8-Osaka è stata la variante predominante nel 2017, la B3-Dublino nel 2018 e la D8-Gir Somnath nel 2019. Sono state inoltre identificate 69 sequenze non ancora classificate dall’OMS e momentaneamente denominate “no named strain”. Venti erano di genotipo D8 e 49 di genotipo B3. Alcune di queste sequenze hanno dato origine a eventi di trasmissione continua, altre a casi sporadici o a piccoli focolai familiari non propagandosi ulteriormente nella popolazione. È stata approfondita l’analisi molecolare di ceppi correlati a importanti eventi epidemici (focolai nosocomiali e familiari) e a casi notificati come sporadici avvenuti a breve distanza geografica e temporale dai focolai. È stato quindi sviluppato il sequenziamento e l’analisi filogenetica di una regione di più di 2000 nucleotidi, comprendente l’N-450 e tutto il gene H (N-450/H). Ciò ha reso possibile valutare la variabilità genetica (intra-variante) di ceppi 100% identici in N-450. L’analisi filogenetica di questa regione ha permesso di osservare che sequenze tra loro identiche nella sola regione N-450 formavano dei cluster e altre invece risultavano non strettamente correlate. In un secondo momento, gli stessi ceppi sono stati sottoposti a sequenziamento dell’intero genoma, la cui analisi filogenetica ha confermato i dati ottenuti in N-450/H, ma raggiungendo un maggior match con l’indagine epidemiologica e risultando più sensibile nel delineare le singole catene di trasmissione. È stato studiato il profilo sierologico di 33 casi confermati di morbillo con storia di vaccinazione documentata nel database regionale MAINF. Nel 18.2% dei casi, il riscontro di negatività in IgG in fase acuta (7-10 giorni dall’esordio del rash) ha suggerito una mancata risposta al vaccino (non-responder) e quindi un fallimento primario della vaccinazione. La gran parte dei casi vaccinati (81.8%) ha mostrato una risposta in IgG in fase acuta e pertanto inquadrabile come fallimento verosimilmente secondario. La capacità di trasmettere l’infezione da parte di soggetti con fallimento vaccinale è stata dimostrata nel 12% dei casi. Infine, i soggetti con fallimento primario avevano un’età mediana all’epoca dell’ultima dose più elevata rispetto a quelli con fallimento secondario (12 anni e 6 anni rispettivamente). Un ulteriore obiettivo del presente progetto è stato quello di analizzare 87 sequenze amminoacidiche della proteina H (target principale degli anticorpi neutralizzanti) identificate in soggetti vaccinati e non vaccinati. Di queste, 30, di cui 7 appartenenti a ceppi di casi vaccinati, presentavano sostituzioni in siti immunoepitopici. Le sostituzioni riscontrate sono state L247S, P247S, A400V, A192T e Q575K. Non sono invece state riscontrate mutazioni in siti funzionali della proteina, come per esempio residui di cisteina importanti per il mantenimento della struttura terziaria, o in siti di legame col recettore, responsabili del riconoscimento e dell’ingresso nella cellula ospite. CONCLUSIONI. L’andamento epidemiologico e genotipico dei casi di morbillo identificato nei 3 anni di studio a Milano e nelle aree limitrofe rispecchia quello riscontrato sul territorio nazionale. L’analisi intra-genotipica condotta ha permesso di identificare complessivamente 16 varianti virali, di cui 4 predominanti e un’elevata variabilità per entrambi i genotipi individuati (D8 e B3). Ciò conferma il pattern tipico nelle aree caratterizzate da un abbassamento delle coperture vaccinali e un aumento dei soggetti suscettibili alla malattia. Per dimostrare l’interruzione della circolazione all’interno del proprio territorio, i paesi devono essere in grado di distinguere le trasmissioni endemiche dai casi importati, in quanto la malattia può essere considerata eliminata solo in assenza di focolai endemici. La circolazione a livello mondiale di un ristretto numero di varianti virali limita l’informazione data dall’analisi filogenetica della regione N-450 e rende più complessa la ricostruzione delle rotte di trasmissione e la caratterizzazione dei focolai epidemici. Inoltre, non consente di ricostruire le catene di trasmissione e identificare i casi di importazione da fonti diverse. È pertanto importante mettere in atto nuove strategie metodologiche per ampliare la “finestra di sequenziamento”. L’analisi dell’intero genoma è risultata sensibile e in grado di ricostruire le catene di trasmissione e identificare i casi di importazione. Questa tecnica risulta tuttavia estremamente laboriosa e costosa e, nell’attuale contesto epidemiologico, non applicabile come metodica di routine. Potrebbe risultare invece la strategia ottimale per i paesi measles-free o che si stanno avvicinando all'eliminazione del morbillo, dove è necessario verificare l’introduzione solo di pochi ceppi virali. I risultati ottenuti nel corso dei 3 anni di dottorato sui ceppi coinvolti in importanti eventi epidemici a Milano e nelle aree limitrofe suggeriscono che l’analisi della regione N-450/H possa essere considerata una valida strategia di implementazione della sorveglianza molecolare in questa fase del programma di eliminazione. Per quanto riguarda lo studio dei casi confermati di morbillo in soggetti vaccinati, i risultati hanno dimostrato che la maggior parte dei fallimenti vaccinali non sono dovuti a una mancata risposta immunitaria (non-responder), ma piuttosto ad una perdita nel tempo della risposta immunologica vaccino-indotta. Tuttavia, la valutazione del titolo anticorpale è stata fatta durante la fase acuta della malattia e non si è potuto valutare quanti soggetti presentavano titoli anticorpali protettivi prima dell’infezione. Questa valutazione avrebbe contribuito a identificare i booster delle IgG in fase acuta causati dall’incontro col virus selvaggio. Il riscontro di una percentuale non trascurabile di casi di morbillo tra soggetti vaccinati che ha dato origine a focolai evidenzia la necessità di mantenere alta l’attenzione nel mettere in atto le misure di contenimento e diffusione della malattia anche in presenza di casi vaccinati. Ulteriori studi multidisciplinari devono essere condotti per confermare i risultati ottenuti e delineare opportuni piani risolutivi. L’analisi amminoacidica della proteina H ha permesso di identificare mutazioni in siti critici della proteina non osservate da studi precedenti. I dati ottenuti sono da un lato rassicuranti in quanto non mostrano la circolazione di mutanti escape, dall’altro documentano una variabilità della proteina H che impone la necessità di un monitoraggio costante. In conclusione, nel presente progetto di dottorato, sono state sviluppate e applicate metodologie innovative risultate utili per la corretta valutazione dello scenario epidemiologico attuale, caratterizzato dalla circolazione di ceppi endemici, dalla continua introduzione di varianti virali e da una quota non trascurabile di fallimenti vaccinali.
INTRODUCTION. Measles virus belongs to the morbillivirus genus of the family Paramyxoviridae. Infection with measles virus results in an extremely contagious exanthematic disease transmitted by air. It often causes severe complications and deaths, is preventable with vaccination and presents requirements for elimination. Italy is one of the 12 European countries where measles transmission is still endemic. The Global Measles and Rubella Strategic Plan 2012–2020 has set the goal of the elimination of endemic measles in the WHO European Region. To achieve this goal, high vaccination coverage must be obtained and maintained (>95%), and a sensitive and quality surveillance system must be ensured. Measles molecular surveillance is a key component to verify the endemic measles elimination, and a crucial tool both to establish any epidemiological link between cases occur in the same period and area, and to identify the importation sources. With the progress of the elimination program, the genetic diversity of circulating measles strains decreases. Continuous air travels and the ease world trade between countries facilitate imports into a given geographical area of viral variants belonging to the same genotype. In this context, traditional laboratory methods can not distinguish endemic transmission from import events of the same viral variant. In addition, as the vaccination program moves forward, an increasing proportion of measles cases occur in vaccinated individuals. New and advanced technologies must therefore allow us to broaden knowledge on measles in vaccinated people, and allow us to identify strains potentially capable of evading the immune response. AIM. The aim of the PhD project is to study and monitor in time the molecular epidemiology of measles in view of the elimination goal, through the develop and the use of innovative molecular and bioinformatic methodologies. Therefore, the research aims to combine the traditional epidemiological methods with the molecular and bioinformatic techniques of the new era. A further objective is to study measles confirmed cases in vaccinated people, in order to assess vaccination failure and to identify any escape mutant in the measles H gene. MATERIALS AND METHODS. From March 2017 to July 2019, biological specimens from patients with suspected measles were collected and analysed as part of the Measles and Rubella Integrated Surveillance System of the Lombardy Region (MoRoNET network). Viral RNA was extracted, and a Real Time RT-PCR was carried out for the measles genome identification. Retro-transcription was performed to all the measles positive samples, and a nested RT-PCR was conducted for the amplification of the N-450 region, in order to perform the genotyping. Samples of interest (N=50) have undergone two emi-nested PCR for the amplification of the H gene. Moreover, the amplification of the complete genome through specific couples of primers (which allow to obtain 10 overlapped fragments) has been conducted on the same samples. Amplicons were sequenced and a phylogenetic analysis was conducted on N-450 region, N-450/H region and on the whole genome, using the bioinformatic programs ClustalX2, BioEdit and MEGA7. Vaccinated measles cases were studied through analysis on serological data obtained from the regional referent laboratory database. In addition, the amino acid sequence of measles H protein (obtained from the conversion of the nucleotide sequences with BioEdit) was analysed in 7 vaccinated measles cases and 80 non-vaccinated measles cases, as control group. Personal, clinical and epidemiological data of measles cases analysed in this study were obtained from the Lombardy Region database of infectious diseases, MAINF. RESULTS. Overall, from March 2017 to July 2019, 885 suspected measles cases reported in Milan and surrounding areas were investigated. The 74.2% of measles cases was confirmed by laboratory investigations. The largest number of measles cases was confirmed in 2017 (50.4%). The age groups 15-39 years and over-39 years were the most affected over the all three years (63.0% and 42.7% of measles cases, respectively). The 92.1% of measles cases was unvaccinated. Regional database MAINF allowed to classify measles cases as sporadic (57.4%) or belonging to outbreaks (42.7%). The 9.7% of measles cases confirmed by our laboratory was outside the examined area during the incubation period of the disease. Genetic characterization was performed by the N-450 morbillivirus region sequencing and was completed with success in 95.3% of measles cases. The genotyping made possible to highlight the continuous co-circulation of two genotypes, D8 (72.9%) and B3 (26.1%). The intra-genotype analysis identified overall 16 viral variants, 8 of them already classified as WHO named strain. In particular, 5 WHO named strains D8 (Mv/Osaka.JPN/29.15, Mvs/London.GBR/21.16/2, MVi/Hulu-Langat.MYS/26.11, MVs/Gir-Somnath.IND/42.16, Mvs/Victoria.AUS/6.18) and 3 WHO named strains B3 (MV/Dublin.IRL/8.16, MVs/Saint-Denis.FRA/36.17, Mvs/Ljubljana.SVN.27.17) have been identified. The named strain D8-Osaka was the predominant genotype variant during the 2017. The named strain B3-Dublin was the predominant genotype variant during the 2018, and the named strain D8-Gir Somnath was the most frequently detected during the 2019. Moreover, 69 sequences not yet classified by the WHO have been identified and called “no-named strain”. Twenty no-named strains belonged to genotype D8 and 49 belonged to genotype B3. Some of them were responsible of continued transmission events, sporadic cases or small familiar outbreaks that did not further spread into the population. Molecular analysis has been deepened on strains correlated to nosocomial and familiar outbreaks and on strains correlated to sporadic cases occurred within short geographical and temporal distances from the outbreaks. It was therefore developed the sequencing and the phylogenetic analysis of a more than 2000 nucleotides region, which includes the N-450 region and the whole H gene (N-450/H). This made possible to evaluate the genetic variability of strains 100% identical in the N-450 region. Phylogenetic analysis of the N-450/H construct allowed to observe clusters within strains with the same N-450 region, whereas others 100% identical in N-450 were not strictly correlated. Subsequently, the whole genome sequencing was carried out on the same strains, and the phylogenetic analysis confirmed data obtained with N-450/H analysis. However, the whole genome sequencing analysis reached a greater match with the epidemiological investigation, and it resulted more sensitive outlining the single chains of transmission. The serological profile of 33 measles cases with a vaccination history was investigated. Negativity in IgG test during the acute phase of the disease (7-10 days from rash) was found in 18.2% of measles cases, suggesting a failure in vaccination response (non-responder) and therefore a primary vaccine failure. The majority of vaccinated measles cases (81.8%) showed an IgG response during the acute phase. Therefore, these cases could be placed in a secondary vaccine failure. Ability to transmit the infection to secondary cases was found in the 12% of vaccinated measles cases. In addition, the median age at the time of the last vaccine dose of measles cases with primary vaccine failure was higher than the one of measles cases with secondary vaccine failure (12 and 6 years old, respectively). Another goal of the present project was to analyse 87 aminoacidic sequences of measles H protein (first target of human neutralizing antibodies) identified in vaccinated and not vaccinated subjects. Of them, 30, of which 7 belonged to vaccinated measles cases, showed amino acid substitutions in antigenic epitopes. The substitutions were L247S, P247S, A400V, A192T, and Q575K. No mutations were found at functional sites of the protein, such as cysteine residues important for the maintenance of the tertiary protein structure, or on binding receptor sites, responsible for the recognition and the entry into the host cell. CONCLUSIONS. The epidemiological trend and genotypes of measles cases identified in Milan and the surrounding areas in the 3 years of study reflect what found on the national territory. The intra-genotyping analysis identified overall 16 viral variants, 4 of them predominant, and a high variability for both the D8 and B3 genotypes. This result confirms the typical pattern of areas characterized from a reduction of vaccination coverage and with an increment of susceptible subjects. To demonstrate the interruption of the virus circulation in the territory, countries must be able to distinguish endemic transmission form imported cases. Indeed, measles disease can be considered eliminated only in the absence of endemic outbreaks. The worldwide circulation of a small number of viral variants limits the information given by the phylogenetic analysis of the N-450 region, and makes more complex the reconstruction of transmission routes, as well as the outbreaks characterization. Furthermore, it is impossible to trace the chains of transmission and identify imported cases from different sources. It is therefore important to implement new methodologic strategies in order to extend the “window sequencing”. The whole genome analysis was sensitive and resulted able to trace the chains of transmission and identify the imported cases. This technique, however, is extremely laborious and expensive, and it is not applicable as routine tool in the actual epidemiological context. It could be instead the optimal strategy for measles-free countries, or for which ones is approaching the measles elimination, with only few cases to verify. The results obtained on strains involved in important epidemic events in Milan and surrounding areas during the 3-years PhD study suggest that the N-450/H analysis could be considered a good implementation strategy of the molecular surveillance in the actual elimination program phase. Regarding the study of measles cases in vaccinated subjects, it can be hypothesized that vaccination failure is not caused by an immunity system failure to vaccination (non-responder), but rather to a decline over the time of the immunity response vaccine-induced. However, the antibody evaluation was made during the acute phase of the disease, and it is not able to evaluate how many subjects had protective antibody titres before the infection. This evaluation would contribute to identified IgG boosters in acute phase caused by the wild-type measles strain exposure. The finding of an important proportion of vaccinated measles cases able to originate outbreaks highlight the necessity to maintain a high attention for the containment measures and for the spread disease control even in presence of vaccinated subjects. More multidisciplinary studies must be conducted to confirm the obtained results and to outline appropriate resolutive planes. Amino acid analysis of the measles H protein has led to identify mutations in critical protein sites observed for the first time. Data obtained are on the one hand reassuring because no escape mutant was found. On the other hand, data document a measles H protein variability which impose a constant monitoring. In conclusion, in this PhD project the innovative techniques developed and applied were found to be useful for the correct evaluation of the actual epidemiological scenario, which is characterized by the circulation of endemic measles strains, the continuous introduction of viral variants and a significant number of vaccine failures.

Vaccines save between 2 million and 3 million lives each year and protect the entire population from more than a dozen life-threatening diseases. Thanks to vaccination, smallpox was eradicated in 1980, and we are on track to eradicate polio. However, despite great strides in the control of measles, one of the most contagious diseases known, the last few years have unfortunately seen an increase in cases. This is why high vaccination coverage—95% or more—is needed, posing a major technical and communication challenge for health workers. Studies show that telling people about the quality, safety, effectiveness and availability of vaccines is not enough to influence behavior change related to immunization, and in general, doesn´t increase coverage. For this reason, it´s necessary to understand the reasons why people choose not to get vaccinated or not get their children vaccinated, in order to begin a two-way respectful dialogue using the best, most effective messages. Given this context, the main objective of these guidelines is to provide tools for staff working in the field of immunization to support effective communication between health personnel and the general population, with the aim of strengthening, maintaining or recovering trust in vaccines and the immunization programs in the Region of the Americas.

In the early twenty-first century, measles was completely eradicated in the United States of America (USA) and almost eliminated in Canada. This was greatly due to most of the population being vaccinated against the virus. In 2018 and 2019, the USA and Canada experienced a rapidly developing measles virus outbreak due to growing debates about vaccine efficacy and side effects. Therefore, some people refused to vaccinate their children against measles, as well as many other life-threatening preventable diseases. This led to a major measles outbreak and health concern in the USA, Canada, and globally. Some countries including the Democratic Republic of the Congo (DRC) reported a significant number of cases and casualties resulting from measles, mainly due to the lack of funding for vaccines, as well as inadequate vaccination coverage in certain socio-demographic areas. People traveling from these countries can easily transmit the disease, though there has been a steep decline in cases since the travel ban due to coronavirus disease-2019 (COVID-19). The number of unvaccinated children currently in the USA and Canada has quadrupled since 2001. Over the past couple of years, most of the measles cases have been diagnosed in those who either did not receive the measles vaccine or complete the recommended doses of the vaccine. This paper reviews the measles outbreak, in recent years, among unvaccinated individuals in the USA, Canada, and globally.

This chapter discusses disease entities that are vaccine preventable. Diseases not likely to be seen by physicians because of near eradication include diphtheria, tetanus, polio, and rabies. However, suspected rabies exposure is common, and initiating post-exposure prophylaxis is essential to preventing rabies. Clearly, other diseases that vaccines have reduced but not eliminated, such as pertussis, hepatitis A, hepatitis B, rotavirus, varicella/zoster, pneumococcal disease, meningococcal disease, influenza, respiratory syncytial virus, and tuberculosis, will be encountered. Haemophilus influenzae type b disease may also rarely be seen. There is great potential for physicians to never see a case of measles, mumps, and rubella, but because clusters of parents have chosen to not vaccinate their children, sporadic outbreaks will continue to occur.

Abstract Chapter 6, ‘Litigation and Legal Challenges to Emergency Orders’, explores the parameters that permit and set limits on the powers of governments to make emergency orders and directions during a pandemic. It examines challenges mounted in diverse countries’ courts during 2020 and 2021, which tested the power of government to make public health orders that encroach on individuals’ legally protected rights and liberties. This chapter considers the invocation of the right to life to justify orders, such as border closures, quarantine, lockdowns, and curfews, and the implications of public health orders made during the pandemic for the right to assemble. It scrutinizes a major English challenge brought on public law grounds against the sufficiency of government orders for the protection of persons living in congregate aged-care residences and the ramifications of the decision for civil actions. The chapter also reviews legal challenges to the imposition of requirements for people to be vaccinated in order to enjoy various ways in which they can participate in the community. In addition, it reviews litigation in the family law context in relation to whether children are vaccinated and the ramifications of such decisions by parents for custodial arrangements in relation to children. It discusses governments’ preparedness to impose restrictive measures to inhibit spread of the virus and the tendency for courts to acquiesce in such measures, provided they can be shown to be required in the interests of public health and be proportionate.

Abstract: Introduction. In the course of their work, medical workers are exposed to a biological factor, including bacterial, viral nature. Medical personnel come into contact with patients with measles, rubella, diphtheria, tuberculosis, hepatitis, coronavirus infection and other infectious diseases. The aim of the study is to assess the humoral immunity by the presence antibodies to the measles, rubella, hepatitis B viruses, to the causative agent COVID-19, tuberculosis and diphtheria bacteria in health care workers. Methods. Antibodies to measles, rubella, hepatitis B viruses, diphtheria and tetanus pathogens were measured in blood serum samples of 1221 MW; total antibodies to mycobacterium tuberculosis - in 120 MW; antibodies to the nucleocapsid protein of the SARS-CoV-2 virus – in 301 MW. The study was carried out by the method of enzyme immunoassay using commercial test systems; antibodies to diphtheria toxoid were detected in the passive hemagglutination reaction. The control group consisted of persons of engineering and technical personnel, comparable in age, gender and work experience. Results. Medical personnel were found to have significantly more frequent detection of seronegative reactions to the presence of antibodies to the hepatitis B virus (40.9% and 13.5%, p<0.001) of measles (28.8% and 3.9%, p<0.05); significantly high prevalence in the presence of total antibodies to mycobacterium tuberculosis (7.5% of cases in medical, 0% of cases of workers in the control group, p<0.05). In comparison with doctors, nurses had a significantly higher prevalence of antibodies to the nucleocapsid of the SARS-CoV-2 virus (38.9% and 23.7%, p<0.05). Conclusions. The study of post-vaccination immunity in medical workers showed the presence of a high proportion of seronegative individuals among vaccinated (viral hepatitis B, measles) medical workers and, accordingly, significant biological risks. A higher seroprevalence in total antibodies to Mycobacterium tuberculosis may also indicate insufficient immune protection among MW. The biological significance of seroprevalence to SARS-CoV-2 virus proteins (for nurses) requires further study.

Multiple jurisdictions have adopted or adapted paid sick leave policies to reduce the likelihood of employees infected with SARS-CoV-2 presenting to work, which can lead to the spread of infection in workplaces. During the COVID-19 pandemic, paid sick leave has been associated with an increased likelihood of workers staying at home when symptomatic. Paid sick leave can support essential workers in following public health measures. This includes paid time off for essential workers when they are sick, have been exposed, need to self-isolate, need time off to get tested, when it is their turn to get vaccinated, and when their workplace closes due to an outbreak. In the United States, the introduction of a temporary paid sick leave, resulted in an estimated 50% reduction in the number of COVID-19 cases per state per day. The existing Canada Recovery Sickness Benefit (CRSB) cannot financially protect essential workers in following all public health measures, places the administrative burden of applying for the benefit on essential workers, and neither provides sufficient, nor timely payments. Table 1 lists the characteristics of a model paid sick leave program as compared with the CRSB. Implementation of the model program should be done in a way that is easy to navigate and quick for employers.

Bovine babesiosis, caused by the apicomplexan parasites Babesiabovisand B. bigemina, is a major tick borne disease of cattle with significant economic importance globally. The vectors of Babesia parasites are R. (Boophilus) annulatusand R. microplus. In Israel these parasites are transmitted manly by R. annulatus. The main goal of the proposal was developing and testing a novel B. bovisvaccine based on stably transfected attenuated B. bovisexpressing the anti-tick Bm86 antigen. This required generating a transfected- attenuated B. bovisparasite containing a bidirectional promoter expressing both, the gfp- bsd selectable marker and the tick vaccine antigen Bm86. The vaccine was tested for its ability to elicit protective immune responses against T. annulatusticks. Efficient control of babesiosis is based on a complex scheme of integrated management, including preventive immunization, anti-babesial chemotherapy and control of tick populations. Live vaccines based on attenuated parasites are the most effective measure to control babesiosis, and are currently used in several countries, including Israel. Live attenuated parasites lead to a chronic infection and development of strong and long term immunity in vaccinated cattle. Still, live vaccines have several limitations, including the difficulty to distinguish among vaccinated and naturally infected cattle and potential for sporadic outbreaks in vaccinated animals. Tick limitation is essential to control babesiosis but the main measure to reduce tick infestation is traditionally approached using acaricides, which is limited by environmental concerns and the development of resistance by the ticks. Alternative tick-control measures including the use of anti-tick vaccines are emerging, and at least partial protective immunity has been achieved against tick vectors by vaccination with recombinant protective tick antigens (ie: Bm86). In addition, the Babesia vaccine development toolbox has been recently expanded with the development of transfection technology in Babesia parasites. In this approved proposal we successfully developed a Babesia live attenuated transfected vaccine, which is able to express a B. bovisMSA-1 signal-Bm86 chimera and eGFP genes under the control of the B. bovisef- 1 and actin promoters respectively. Genetic analysis demonstrated specific stable integration of the transfected genes in the expected ef-1 locus, and immunofluorescence analysis confirmed expression of Bm86 in the surface of transfected parasites. When applied to splenectomized calves, the transfected parasites were able to cause persistent B. bovisinfection with production of antibodies reactive with Bm86 for at least six months. In addition, partial protection against ticks was also observed upon challenging the vaccinated animals with R. annulatuslarvae. However, when used on intact calves, the vaccine failed to elicit detectable immune responses against Bm86, and we are still in the process of interpreting the data and make necessary changes in our experimental approaches. Overall, the results obtained here represent a step forward towards the development of integrated vaccines against both ticks and tick –borne pathogens, using the Babesia attenuated parasites as a platform to the delivery of exogenous protective antigens