Seroepidemiology of mumps in Europe (1996-2008): why do outbreaks occur in highly vaccinated populations?

Questionable Immunity to Mumps among Healthcare Workers in Italy-A Cross-Sectional Serological Study

Highly contagious diseases, such as mumps, are a global concern as new epidemics continue to emerge, even in highly vaccinated populations. The risk of transmission and spread of these viruses is even higher for individuals who are more likely to be exposed, including healthcare workers (HCWs). In healthcare settings, both HCWs and patients are at risk of infection during the care process, potentially leading to nosocomial epidemic outbreaks. Mumps is often underestimated compared with measles and rubella, despite being milder and less likely to spread. In fact, the risk of complications following mumps infection is extremely high, especially if the disease occurs in adulthood. The measles-mumps-rubella (MMR) vaccine has been shown to be an excellent preventive measure. Unfortunately, the mumps component appears to be less effective in inducing immunity than those for measles and rubella (two-dose effectiveness of 85%, 95% and 97%, respectively). The main aim of our study was to investigate the prevalence of detectable mumps antibodies (serum IgG antibodies) in a cohort of Italian and foreign HCWs in relation to personal and occupational factors. We included in the study 468 subjects who underwent health surveillance at the Occupational Medicine Unit of the Tor Vergata Polyclinic in Rome during the period from January 2021 to March 2023. In our study, the proportion of HCWs found to be unprotected against mumps was very high (8.3%), and those found to be immune are below the WHO threshold for herd immunity (95%). From our data, it seems essential that all occupational health services carry out an accurate screening with a dose of anti-mumps antibodies to assess serological protection before starting a job, regardless of an individual's vaccination history. This approach is proving to be beneficial, accurate, as it allows all serologically non-immune individuals to be vaccinated in the workplace, including those who would be protected by their vaccination history but have lost the antibody response.

Vaccine-preventable diseases: Immune response in a large population of healthcare students

BACKGROUND

Students in medicine and other health professions are exposed to numerous occupational hazards, primarily biological hazards, during their academic careers at university. The aim of the present study was to investigate the seroprevalence characteristics of anti-HBsAg, anti-Measles, anti-Mumps, anti-Rubella and anti-Varicella IgG antibodies in healthcare students of a large teaching hospital in Rome.

METHODS

To accomplish the study's aims, antibody serology data were gathered from students of Medicine and Surgery, Dentistry, and Health Professions at the Catholic University of the Sacred Heart (Rome Campus) during their first Health Surveillance visit, that took place from 2013 to 2023.

RESULTS

Our study sample included 2523 students, 44.4 % were protected against Hepatitis B, 87.3 % against measles, 85.5 % against mumps, 94.6 % rubella and 95.2 % against varicella. Differences in antibody coverage between age groups were statistically significant (p < 0.001), except for mumps. It found a lower probability of having seronegative anti-HBVs with an older date since the presumed primary vaccination.

CONCLUSION

In our sample, seropositivity rate against vaccine-preventable diseases, especially for Hepatitis B, was often inadequate to prevent possible biological risks connected with the activities carried out on the ward.

The Concordance between Mumps and Rubella Sero-Positivity among the Israeli Population in 2015

Mumps and rubella are vaccine-preventable viral diseases through the measles-mumps-rubella-varicella (MMRV) vaccine, administered at 12 months and again at 6 years. We assessed the sero-prevalence of mumps and rubella, identified factors associated with sero-negativity, and evaluated concordance between mumps and rubella sero-positivity. A national cross-sectional sero-survey was conducted on samples collected in 2015 by the Israel National Sera Bank. Samples were tested for mumps and rubella IgG antibodies using an enzyme-linked immunosorbent assay. Of 3131 samples tested for mumps IgG, 84.8% (95%CI: 83.5–86.0%) were sero-positive. Sero-negativity for mumps was significantly associated with age (high odds ratios observed in infants younger than 4 years and 20–29 years old subjects). Of 3169 samples tested for rubella IgG antibodies, 95.2% (95%CI: 94.4–95.9%) were sero-positive. Rubella sero-negativity was significantly associated with age (high odds ratios observed in children younger than 4 years old and adults older than 30 years), males, Jews, and others. Concordant sero-positivity for both mumps and rubella viruses was observed in 83.9% of the tested samples. The Israeli population was sufficiently protected against rubella but not against mumps. Since both components are administered in the MMRV vaccine simultaneously, the mumps component has a lower uptake than rubella and quicker waning.

Response to Vaccination against Mumps in Medical Students: Two Doses Are Needed

Mumps is a vaccine-preventable infectious disease diffuse worldwide. The implementation of mumps vaccination reduced largely the spread of infection. On 11,327 Medical School students the prevalence of mumps positive antibodies was evaluated according to dose/doses of vaccine, year of birth and sex. Compliance to mumps vaccine was low in students born before 1990 but increased consistently after this year, above all compliance to two doses, due to the implementation of the vaccine offer. Positivity of mumps antibodies is significantly (p < 0.0001) lower in students vaccinated once (71.2%) compared to those vaccinated twice (85.4%). In addition, students born after 1995, largely vaccinated twice, showed a seropositivity near to 90%. Further, females had a significantly (p < 0.0001) higher proportion of positive antibodies after vaccination than males, both one (74.6% vs. 64.7%) and two doses (86.8% vs. 82.9%). Finally, seropositivity after two vaccine doses remains high (86.1%) even 15 years after the second dose. In conclusion, the research highlighted that vaccination against mumps reaches a good level of coverage only after two doses of vaccine persisting at high levels over 15 years and induces a more significant response in females.

Measles, mumps, rubella prevention: how can we do better?

INTRODUCTION

Measles, mumps, and rubella incidence decreased drastically following vaccination programs' implementation. However, measles and mumps' resurgence was recently reported, outbreaks still occur, and challenges remain to control these diseases.

AREAS COVERED

This qualitative narrative review provides an objective appraisal of the literature regarding current challenges in controlling measles, mumps, rubella infections, and interventions to address them.

EXPERT OPINION

While vaccines against measles, mumps, and rubella (including trivalent vaccines) are widely used and effective, challenges to control these diseases are mainly related to insufficient immunization coverage and changing vaccination needs owing to new global environment (e.g. traveling, migration, population density). By understanding disease transmission peculiarities by setting, initiatives are needed to optimize vaccination policies and increase vaccination coverage, which was further negatively impacted by COVID-19 pandemic. Also, awareness of the potential severity of infections and the role of vaccines should increase. Reminder systems, vaccination of disadvantaged, high-risk and difficult-to-reach populations, accessibility of vaccination, healthcare infrastructure, and vaccination services management should improve. Outbreak preparedness should be strengthened, including implementation of high-quality surveillance systems to monitor epidemiology. While the main focus should be on these public health initiatives to increase vaccination coverage, slightly more benefits could come from evolution of current vaccines.

Evaluation of Immunity for Mumps among Vaccinated Medical Students

Healthcare workers are considered at higher risk for mumps infection than the general population. Since 2017, the national immunization plan recommended the administration of a dose of measles–mumps–rubella (MMR) vaccine to the healthcare operators who are unable to demonstrate a complete vaccination history or that are seronegative for at least one of the three agents. Regarding mumps infection, based on actual concerns regarding the loss of protection over the years after vaccination, the Advisory Committee on Immunization Practices (ACIP) recommended to administer a third dose of vaccine to operators previously vaccinated with two doses of MMR vaccine who belong to a group at increased risk of mumps infection in the event of an epidemic. This guideline, however, is not currently followed in Italy, resulting in a potential risk for vaccinated operators to become unprotected from mumps over the years. The aim of our study is to evaluate the persistence of a protective antibody level for mumps among medical students vaccinated during infancy or adolescence, at the start of their hospital internship. We retrospectively evaluated mumps-specific IgG levels in a group of medical students, in the period from 1 January to 31 December 2020. We evaluated the persistence of the detectable level of mumps-specific antibodies in relation to their vaccinal status, gender and time elapsed from vaccination. We found that 17.4% (65 subjects) of our sample were seronegative for mumps. The univariate analysis showed a significant difference in serological protection between male and female gender (77.0% vs. 86.2%; p < 0.05 with chi² test) and between age classes (86.5% vs. 76.4%; p < 0.05 for subjects aged 18–23 years and over 23 years, respectively). Female gender was significantly related to higher serological protection even after adjusting for age classes and number of vaccine doses administered in a multivariate analysis model. Our study shows a substantial percentage of subjects lacking a protective mumps titer among medical students who were vaccinated in childhood. Given the higher risk of infection among those subjects, routine pre-employment screening should be performed among those operators regardless of their vaccination history and a third dose of MMR should be offered to unprotected students.

Immunity to vaccine-preventable diseases among paediatric healthcare workers in Denmark, 2019

Background

Healthcare workers (HCW) have been identified as index cases in disease outbreaks of vaccine-preventable diseases (VPD) in hospitals.

Aim

We investigated whether Danish paediatric HCW were protected against selected serious VPD.

Methods

We included 90% of staff members from two paediatric departments. All 555 HCW (496 women) supplied a blood sample for serology and filled in a questionnaire. Antibodies were measured with enzyme immunoassay against measles, mumps, rubella (MMR), varicella zoster, pertussis toxin and diphtheria toxin.

Results

Protective levels of IgG were found for measles (90.3%), mumps (86.5%), rubella (92.3%), varicella (98.6%) and diphtheria (80.5%). We found seropositivity for all three MMR components in 421 (75.9%) HCW, lowest in those younger than 36 years (63.3%). Only 28 (5%) HCW had measurable IgG to pertussis. HCW with self-reported immunity defined as previous infection or vaccination, had protective levels of IgG against measles, mumps, rubella and varicella in 87.4–98.8% of cases, not significantly higher than in those not reporting immunity. Previous history of disease had a high positive predictive value (PPV) of 96.8–98.8%. The PPV for previous vaccination ranged from 82.5% to 90.3%. In contrast, negative predictive values of self-reported history of disease and vaccination were remarkably low for all diseases.

Conclusion

The immunity gaps found primarily in young HCW indicate a need for a screening and vaccination strategy for this group. Considering the poor correlation between self-reported immunity and seropositivity, efforts should be made to check HCW’s immune status in order to identify those who would benefit from vaccination.

Identification and description of mumps cases in a non-outbreak setting and evaluation of the effectiveness of mumps-containing vaccines over time

Mumps outbreaks among previously vaccinated young adults raise concerns regarding waning vaccine immunity. This study identified, described and assessed the changing incidence of mumps cases following mumps-containing vaccination (MMR/MMRV) in a non-mumps outbreak setting. Potential cases between 1996 and 2018 were identified by the international classification of disease codes or by mumps laboratory test orders among Kaiser Permanente Northern California members. Medical charts were reviewed to confirm diagnoses, timing relative to vaccination and clinical characteristics. Among 474 potential cases, 257 (54.2%) were confirmed after chart review. A third of the cases were <10 years old at diagnosis and 48% were over 25 years. Most cases (92.2%) had parotitis and 5% of males had orchitis. Mumps rates decreased from 8.5 to 1.8/1,000,000 person-years as time since the second MMR/MMRV dose increased from <2 years to ≥10 years. Similarly, rates decreased from 16.3 to 3/1,000,000 person-years after at least 1 dose of MMR/MMRV. Mumps rates were higher among children aged ≤10 years compared with older age groups. In conclusion, in the context of a non-outbreak setting, this study suggests that waning of vaccine immunity to mumps appeared to have minimal clinical impact.

Australian mumps serosurvey 2012-2013: any cause for concern?

Objectives

To determine population-level immunity to mumps in Australia.

Methods

We tested randomly selected specimens from people aged 1-49 years using the Enzygnost anti-parotitis IgG enzyme immunoassay from an opportunistically collected serum bank in 2012-2013. Weighted estimates of the proportion seropositive and equivocal for mumps-specific IgG antibody were determined by age group and compared with two previous national serosurveys conducted in 2007-2008 and 1997-1998.

Results

Overall, 82.1% (95% CI 80.6-83.5%) of 2,729 specimens were positive or equivocal for mumps-specific IgG antibodies (71.1% positive [95% CI 69.4-72.9%]; 10.9% equivocal [95% CI 9.8-12.2%]). The proportion positive or equivocal was higher in 2012-2013 (82.1%) than in 2007-2008 (75.5%) and 1997-1998 (72.5%), but varied by age. The proportion positive or equivocal in 2012-2013 was above 80% for all age groups older than 1 year except for 30-34 year olds, corresponding to the 1978-1982 birth cohort previously identified as most likely to have missed out on a second MMR vaccine dose.

Conclusion

Seropositivity to mumps in 2012-2013 was well-maintained compared with previous serosurveys. Low mumps notifications over this period in Australia suggest an absence of community-based transmission of mumps infection in the general population, but recent outbreaks among Aboriginal adolescents and young adults in close-contact settings, despite high 2-dose MMR coverage, suggest that seroprotection may be insufficient in other similar settings in Australia.Seropositivity to mumps in 2012-2013 was well-maintained compared with previous serosurveys. Low mumps notifications over this period in Australia suggest an absence of community-based transmission of mumps infection in the general population, but recent outbreaks among Aboriginal adolescents and young adults in close-contact settings, despite high 2-dose MMR coverage, suggest that seroprotection may be insufficient in other similar settings in Australia.

High risk of mumps infection in children who received one dose of mumps-containing vaccine: waning immunity to mumps in children aged 2-5 years from kindergartens in Jiangsu Province, China

BACKGROUND

During the period of immunization with a single-dose measles-mumps-rubella (MMR) vaccine, which has been available since 2008in China, the incidence of mumps in children aged 2-5 years has been high. The aim of this study was to determine the immunity profile of mumps in children aged 2-5 years as part of the assessment of the MMR vaccination strategy.

METHODS

A cross-sectional survey of IgG antibodies against mumps virus in children aged 2-5 years was performed. Analysis by enzyme-linked immune sorbent assay(ELISA)was performed to measure IgG antibodies against mumps virus in the sera of 2-to5-year-old children who had been vaccinated with at least one dose of MMR vaccine.

RESULTS

Mumps outbreaks mainly occurred in kindergarten and primary schools and primarily involved children in kindergarten from 2015-2016 in Jiangsu Province. In total, 4,033 children were surveyed. The overall seroprevalence of mumps antibodies was 79.0% (95% CI:78.4-79.6), and the geometric mean concentration (GMC) was 323.6 mIU/ml (309.0-338.8). Both univariate and multivariate survival analysis of seroprevalence showed that several factors contributed to having significant seroprevalence among the 2-to-5-year-old group (P < .05). The seroprevalence of children with a single-dose MMR vaccine regimen (78.4%, 95% CI: 77.8-80.4) was significantly lower than that of children with a two-dose MMR vaccine regimen (96.5%, 95% CI: 88.6%-96.1%). The seroprevalence rate was negatively correlated with time since inoculation (P < .01).

CONCLUSION

Children who received a single dose of MMR vaccine in kindergarten, particularly the 2-year-old group in the northern region of Jiangsu Province, China, are at high risk of mumps infection. Our study demonstrates thata single-dose MMR vaccine regimen has a limited effect on controlling mumps, which highlights the benefit of introducing a two-dose MMR vaccine schedule.

Current Status of Mumps Virus Infection: Epidemiology, Pathogenesis, and Vaccine

Mumps is an important childhood infectious disease caused by mumps virus (MuV). We reviewed the epidemiology, pathogenesis, and vaccine development of mumps. Previous studies were identified using the key words “mumps” and “epidemiology”, “pathogenesis” or “vaccine” in MEDLINE, PubMed, Embase, Web of Science, and Google Scholar. We excluded the articles that were not published in the English language, manuscripts without abstracts, and opinion articles from the review. The number of cases caused by MuV decreased steeply after the introduction of the mumps vaccine worldwide. In recent years, a global resurgence of mumps cases in developed countries and cases of aseptic meningitis caused by some mumps vaccine strains have renewed the importance of MuV infection worldwide. The performance of mumps vaccination has become an important issue for controlling mumps infections. Vaccine development and routine vaccination are still effective measures to globally reduce the incidence of mumps infections. During outbreaks, a third of MMR vaccine is recommended for groups of persons determined by public authorities.

Seroepidemiology of Measles, Mumps and Rubella on Bonaire, St. Eustatius and Saba: The First Population-Based Serosurveillance Study in Caribbean Netherlands

The National Immunization Program (NIP) on Bonaire, St. Eustatius and Saba (i.e., Caribbean Netherlands (CN)) includes the measles-mumps-rubella (MMR) vaccine since 1988/89. Seroepidemiological data is an important tool to evaluate the NIP, hence a cross-sectional representative population-based serosurveillance study was conducted for the first time in CN in mid-2017. Participants (n = 1829, aged 0-90 years) donated a blood sample and completed a health-related questionnaire. MMR-specific IgG antibodies were determined using a bead-based multiplex immunoassay and risk factors were analyzed using logistic regression models. Overall seroprevalence was high for measles (94%), but lower for mumps and rubella (both 85%). In NIP eligibles, including women of childbearing age, rubella seroprevalence (88%) exceeded the threshold for protection (85%); however, for measles (89%) this protective level (95%) was not met. MMR seropositivity was lowest in children who became CN resident at 11-17 years of age (especially for measles (72%)), mostly originating from Latin America and other non-Western countries. Interestingly, rubella seroprevalence was lowest in non-NIP eligible adults from Dutch overseas territories and Suriname (75%). Taken together, MMR immunity is generally good in CN, nonetheless some risk groups were identified. Additionally, we found evidence for a unique island epidemiology. In light of recent regional measles outbreaks, disease monitoring remains of utmost importance.

Resurgence risk for measles, mumps and rubella in France in 2018 and 2020

Large measles and mumps outbreaks recently occurred throughout Europe and the United States. Aim: Our aim was to estimate and map the risk of resurgence for measles, mumps and rubella in France. Methods: We used a multi-cohort model combining seroprevalence information, vaccine coverage and social contact data. Results: The overall outbreak risk for France in 2018 was highest for mumps, remained significant for measles despite a recent measles outbreak and was low for rubella. Outbreak risks were heterogeneous between departments, as the effective reproduction numbers for 2018 ranged from 1.08 to 3.66. The seroprevalence, and therefore the risk of measles and rubella infection, differed significantly between males and females. There was a lower seroprevalence, and therefore a higher risk, for males. Infants of less than 1 year would be seriously affected in a future outbreak of measles, mumps or rubella, but the highest overall caseload contribution would come from teenagers and young adults (10–25 years old). Conclusions: The high risk for teenagers and young adults is of concern in view of their vulnerability to more severe measles, mumps and rubella disease and complications.

Genomic non-coding regions reveal hidden patterns of mumps virus circulation in Spain, 2005 to 2015

Since mumps vaccination was introduced in 1981 in Spain, the incidence of the disease has dropped significantly. However, cyclic epidemic waves and outbreaks still occur, despite high vaccination coverage. The World Health Organization (WHO) recommends genotyping to trace the pattern of mumps virus (MuV) circulation. Genotype H was predominant in Spain, but was replaced in 2005 by genotype G which has subsequently remained dominant. Of the small hydrophobic protein gene sequences, 78% are identical and belong to the MuVi/ Sheffield.GBR.1.05/[G]-variant. Aim: Our study aimed to investigate whether the circulation of MuV strains in Spain was continuous after the emergence of genotype G in 2005. Method: We obtained 46 samples from Spanish patients infected with MuVi/Sheffield.GBR.1.05/[G] during two epidemic waves and analysed them using new molecular markers based on genomic non-coding regions (NCRs) that discriminate subvariants of this virus strain. Results: Phylogenetic analyses of the nucleoprotein–phosphoprotein and matrix protein–fusion protein NCR indicated strain replacement after a drop in incidence in 2009, which had not been detectable by SH sequencing. Clustering of sequences from patients epidemiologically linked in the same outbreak suggests a potential use for these NCRs in outbreak characterisation. Conclusion: We suggest to consider their use in conjunction with the SH gene in the future WHO recommendations for MuV epidemiological surveillance.

Pre-vaccination IgG screening for mumps is the most cost-effectiveness immunization strategy among Health Care Workers

Health Care Workers (HCWs) have an increased risk of contracting contagious disease, including mumps. In January 2017 the Italian National Vaccine Prevention Plan 2017-2019, recommended the administration of a dose of MMR vaccine (Measles-Mumps-Rubella) to the Health Care Workers (HCWs) that, working in a risky environment, did not carry out the complete vaccination cycle of MMR or that are seronegative for at least one of the three vaccine viruses. In October of the same year, the Advisory Committee on Immunization Practices (ACIP) recommended a third dose of a vaccine containing Mumps Virus for people previously vaccinated with 2 doses, belonging to a group or to a population at increased risk of acquire mumps in the event of an epidemic. We analyzed the clinical records and values of mumps-specific IgG antibodies of 3032 HCWs (mean age 32.80 ± 10.75 years), that underwent occupational health surveillance between January 1st 2017 and March 31th 2018. The HCWs were also screened for measles, rubella, mumps using serological methods. 13% (405) was seronegative for mumps, especially among HCWs between 18 and 36 years. We calculated the cost-effectiveness of two-doses and three-doses MMR vaccination. The cost of vaccination without screening was significantly more expensive (cost difference: 99 712 € and 184 996 €) both in case of two-dose and three-dose MMR vaccination respectively. Our study suggests that, in HCWs, the assessment of the mumps antibody titer before vaccination may be a useful complement to vaccination itself, because it is more accurate and cost-effective than direct immunization of unvaccinated subjects.

Development and Use of an Endpoint Titration Assay To Characterize Mumps IgG Avidity following Measles, Mumps, and Rubella Vaccination and Wild-Type Mumps Infection

Waning mumps IgG antibody and incomplete IgG avidity maturation may increase susceptibility to mumps virus infection in some vaccinees. To measure mumps IgG avidity, serum specimens serially diluted to the endpoint were incubated on a commercial mumps-specific IgG enzyme immunoassay and treated with the protein denaturant diethylamine (60 mM, pH 10). End titer avidity indices (etAIs [percent ratio of detected diethylamine-resistant IgG at endpoint]) were calculated. Unpaired serum specimens (n = 108) from 15-month-old children living in a low-incidence setting were collected 1 month and 2 years after the first measles, mumps, and rubella vaccine dose (MMR1) and tested for mumps avidity. Per the receiver operating characteristic curve, the avidity assay is accurate (area under the curve, 0.994; 95% confidence interval [CI], 0.956 to 1.000), 96.5% sensitive (95% CI, 87.9 to 99.6%), and 92.2% specific (95% CI, 81.1 to 97.8%) at an etAI of 30%. When 9 sets of paired serum specimens collected 1 to 60 months post-MMR1 were tested for mumps and measles IgG avidity using comparable methods, the mumps etAI increased from 11% to 40 to 60% in 6 months. From 6 to 60 months, avidity was sustained at a mean etAI of 50% (95% CI, 46 to 54%), significantly lower (P  < 0.0001) than the mean measles etAI of 80% (95% CI, 74 to 86%). Mean etAIs in children 2 years post-MMR1 (n = 51), unvaccinated adults with distant mumps disease (n = 29), and confirmed mumps cases (n = 23) were 54, 62, and 57%, respectively. A mumps-specific endpoint avidity assay was developed and validated, and mumps avidity was determined to be generally sustained at etAIs of 40 to 60%, reaching etAIs of >80% in some individuals.IMPORTANCE Numerous outbreaks of mumps have occurred in the United States among two-dose measles-mumps-rubella (MMR)-vaccinated populations since 2006. The avidity of mumps-specific IgG antibodies may affect susceptibility to mumps virus infection in some vaccinated individuals. To accurately measure mumps avidity, we developed and validated a mumps-specific IgG avidity assay that determines avidity at the endpoint titer of serially diluted serum specimens, providing results that are independent of IgG concentration. At low antibody titers, endpoint methods are considered more accurate than methods that determine avidity at a single dilution. We determined that 6 months after the first MMR dose, mumps IgG avidity is high and generally sustained at avidity indices of 40 to 60%, reaching values of >80% in some individuals. Additionally, 4% (4/103) of individuals had avidity indices of ≤30% (low avidity) 2 years after vaccination. Inadequate mumps avidity maturation may be one factor influencing susceptibility to mumps virus infection among previously vaccinated or naturally infected individuals.

Spatial, temporal, and spatiotemporal analysis of mumps in Guangxi Province, China, 2005-2016

Background

The resurgence of mumps around the world occurs frequently in recent years. As the country with the largest number of cases in the world, the status of mumps epidemics in China is not yet clear. This study, taking the relatively serious epidemic province of Guangxi as the example, aimed to examine the spatiotemporal pattern and epidemiological characteristics of mumps, and provide a scientific basis for the effective control of this disease and formulation of related health policies.

Methods

Geographic information system (GIS)-based spatiotemporal analyses, including spatial autocorrelation analysis, Kulldorff’s purely spatial and space-time scan statistics, were applied to detect the location and extent of mumps high-risk areas. Spatial empirical Bayesian (SEB) was performed to smoothen the rate for eliminating the instability of small-area data.

Results

A total of 208,470 cases were reported during 2005 and 2016 in Guangxi. Despite the fluctuations in 2006 and 2011, the overall mumps epidemic continued to decline. Bimodal seasonal distribution (mainly from April to July) were found and students aged 5–9 years were high-incidence groups. Though results of the global spatial autocorrelation based on the annual incidence largely varied, the spatial distribution of the average annual incidence of mumps was nonrandom with the significant Moran’s I. Spatial cluster analysis detected high-value clusters, mainly located in the western, northern and central parts of Guangxi. Spatiotemporal scan statistics identified almost the same high-risk areas, and the aggregation time was mainly concentrated in 2009–2012.

Conclusion

The incidence of mumps in Guangxi exhibited spatial heterogeneity in 2005–2016. Several spatial and spatiotemporal clusters were identified in this study, which might assist the local government to develop targeted health strategies, allocate health resources reasonably and increase the efficiency of disease prevention.

Electronic supplementary material

The online version of this article (10.1186/s12879-018-3240-4) contains supplementary material, which is available to authorized users.

Serological survey of mumps antibodies in adults in the Czech Republic and the need for changes to the vaccination strategy

Mumps outbreaks, especially in adolescents and young adults, have been reported in the Czech Republic. The aim of the presented study was to determine the seroprevalence of specific IgG antibodies against mumps in the adult population of the Czech Republic. The study was designed as a multicenter serological survey of adults aged 18 years and over. Specific IgG antibodies against mumps were detected in blood samples using an enzyme-linked immunosorbent assay (ELISA). A total of 1,911 serum samples were examined. The overall seropositivity reached 55.3%. In individual age groups, the highest seropositivity 63% (63.5-65.2%) was recorded in adults aged 40 years and over; the lowest seropositivity was found in adults aged 18-29 years (27.4%). The difference in seropositivity rate between the 18-29 years age group and the 40 years and over age groups was statistically significant (p < 0.001). Only the 18-29 years age group included both vaccinated and unvaccinated (born in the pre-vaccine era) individuals. In vaccinated individuals, seropositivity was reported in only 19.1% of persons; in unvaccinated individuals, seropositivity reached 48.2%. Our results demonstrate the long-term persistence of antibodies following natural infection and the decrease in seropositivity that occurs after vaccination over time. This immunity waning may account for the higher susceptibility of adolescents and young adults to mumps. Therefore, the current vaccination program in the Czech Republic could be considered as less effective. It will be modified with the shifting of the second dose of vaccine from two years of age to the preschool age.

Mumps in the Eastern Bohemia Region of the Czech Republic - a Serological Survey 2008-2012

BACKGROUND

The incidence of mumps has decreased in many countries since the introduction of vaccination programmes, however, in the past decade a rapid increase in the disease occurrence has been reported worldwide. The reason for this situation is still not clear. We present the results of a serological survey carried out in the Eastern Bohemia Region of the Czech Republic during the years 2008-2012.

METHODS

In total, 2,536 samples of 2,034 patients were examined during the study period. The study cohort was divided into two groups, one consisted of individuals born before the introduction of mandatory vaccination and the other one comprised individuals born after mandatory vaccination started. For the serology analyses the ELISA kits RIDASCREEN Mumpsvirus IgM and IgG (R-Biopharm®, Germany) were used.

RESULTS

Out of 2,536 samples (including paired sera), 23.9% (n=606) were positive and 12% (n=304) had equivocal results. Most of the positive samples were obtained from patients aged 17-20 years. Significantly more (p<0.05) positive patients were born after the start of the national vaccination programme (patient group 2) (22.8%) compared to those born before its start (patient group 1) (13.7%). Interestingly, the analysis of data showed that 75.3% of patients falling into group 1 had anti-mumps IgG antibodies, which means that they had contracted mumps, whilst 23.5% of patients of group 2 had undetectable IgG antibodies, even though they should have been vaccinated.

CONCLUSION

The data from our study, with a low number of positive samples in the first years of the study and an increase in the last two years, could suggest the occurrence of outbreaks every 4-6 years.

Mumps Virus SH Protein Inhibits NF-κB Activation by Interacting with Tumor Necrosis Factor Receptor 1, Interleukin-1 Receptor 1, and Toll-Like Receptor 3 Complexes

The mumps virus (MuV) small hydrophobic protein (SH) is a type I membrane protein expressed in infected cells. SH has been reported to interfere with innate immunity by inhibiting tumor necrosis factor alpha (TNF-α)-mediated apoptosis and NF-κB activation. To elucidate the underlying mechanism, we generated recombinant MuVs (rMuVs) expressing the SH protein with an N-terminal FLAG epitope or lacking SH expression due to the insertion of three stop codons into the SH gene. Using these viruses, we were able to show that SH reduces the phosphorylation of IKKβ, IκBα, and p65 as well as the translocation of p65 into the nucleus of infected A549 cells. Reporter gene assays revealed that SH interferes not only with TNF-α-mediated NF-κB activation but also with IL-1β- and poly(I·C)-mediated NF-κB activation, and that this inhibition occurs upstream of the NF-κB pathway components TRAF2, TRAF6, and TAK1. Since SH coimmunoprecipitated with tumor necrosis factor receptor 1 (TNFR1), RIP1, and IRAK1, we hypothesize that SH exerts its inhibitory function by interacting with TNFR1, interleukin-1 receptor type 1 (IL-1R1), and TLR3 complexes in the plasma membrane of infected cells.IMPORTANCE The MuV SH has been shown to impede TNF-α-mediated NF-κB activation and is therefore thought to contribute to viral immune evasion. However, the mechanisms by which SH mediates NF-κB inhibition remained largely unknown. In this study, we show that SH interacts with TNFR1, IL-1R1, and TLR3 complexes in infected cells. We thereby not only shed light on the mechanisms of SH-mediated NF-κB inhibition but also reveal that SH interferes with NF-κB activation induced by interleukin-1β (IL-1β) and double-stranded RNA.

Challenges in Interpretation of Diagnostic Test Results in a Mumps Outbreak in a Highly Vaccinated Population

In spite of a greatly reduced incidence rate due to vaccination, mumps outbreaks continue to occur in several areas of the world, sometimes in vaccinated populations. This article describes an outbreak in a highly vaccinated population in southwestern Ontario, Canada, and the challenges encountered in interpreting the results of diagnostic tests used in the outbreak. During the outbreak, patients were interviewed and classified according to the outbreak case definition, and specimens were collected for diagnostic testing according to Ontario guidelines. Twenty-seven individuals were classified as confirmed cases (n = 19) or suspect cases (n = 8) according to the case definition, only 9 of which were laboratory-confirmed cases: 7 confirmed by reverse transcriptase PCR (RT-PCR) and 2 by IgM serology. All 19 confirmed cases represented patients who were associated with secondary schools in the local area and had been vaccinated against mumps with one (n = 2) or two (n = 17) doses of the measles-mumps-rubella (MMR) vaccine. This is the first published report of an outbreak of mumps in Ontario in which all confirmed cases had been vaccinated against the disease. It highlights the limitations of and difficulties in interpreting current mumps diagnostic tests when used in vaccinated individuals.

Synthesis of human parainfluenza virus 4 nucleocapsid-like particles in yeast and their use for detection of virus-specific antibodies in human serum

The aim of this study was to produce human parainfluenza virus type 4 (HPIV4) nucleocapsid (N) protein in yeast Saccharomyces cerevisiae expression system, to explore its structural and antigenic properties and to evaluate its applicability in serology. The use of an optimized gene encoding HPIV4 N protein amino acid (aa) sequence GenBank AGU90031.1 allowed high yield of recombinant N protein forming nucleocapsid-like particles (NLPs) in yeast. A substitution L332D disrupted self-assembly of NLPs, confirming the role of this position in the N proteins of Paramyxovirinae. Three monoclonal antibodies (MAbs) were generated against the NLP-forming HPIV4 N protein. They recognised HPIV4-infected cells, demonstrating the antigenic similarity between the recombinant and virus-derived N proteins. HPIV4 N protein was used as a coating antigen in an indirect IgG ELISA with serum specimens of 154 patients with respiratory tract infection. The same serum specimens were tested with previously generated N protein of a closely related HPIV2, another representative of genus Rubulavirus. Competitive ELISA was developed using related yeast-produced viral antigens to deplete the cross-reactive serum antibodies. In the ELISA either without or with competition using heterologous HPIV (2 or 4) N or mumps virus N proteins, the seroprevalence of HPIV4 N-specific IgG was, respectively, 46.8, 39.6 and 40.3% and the seroprevalence of HPIV2 N-specific IgG-47.4, 39.0 and 37.7%. In conclusion, yeast-produced HPIV4 N protein shares structural and antigenic properties of the native virus nucleocapsids. Yeast-produced HPIV4 and HPIV2 NLPs are prospective tools in serology.

Waning immunity against mumps in vaccinated young adults, France 2013

In 2013, 15 clusters of mumps were notified in France; 72% (82/114) of the cases had been vaccinated twice with measles-mumps-rubella vaccine. To determine whether the risk of mumps increased with time since the last vaccination, we conducted a case-control study among clusters in universities and military barracks. A confirmed case had an inflammation of a salivary gland plus laboratory confirmation in 2013. A probable case presented with inflammation of a salivary gland in 2013 either lasting for > 2 days or with epidemiological link to a confirmed case. Controls had no mumps symptoms and attended the same university course, student party or military barracks. We collected clinical and vaccination data via web questionnaire and medical records. We calculated adjusted odds ratios (aOR) using logistic regression. 59% (50/85) of cases and 62% (199/321) of controls had been vaccinated twice. The odds of mumps increased for twice-vaccinated individuals by 10% for every year that had passed since the second dose (aOR 1.10; 95% confidence interval (CI): 1.02-1.19; p = 0.02). Mumps immunity waned with increasing time since vaccination. Our findings contributed to the French High Council of Public Health's decision to recommend a third MMR dose during outbreaks for individuals whose second dose dates > 10 years.

Seroprevalence of vaccine-preventable diseases among young children in the United Arab Emirates

OBJECTIVES

In the United Arab Emirates (UAE), many vaccine-preventable diseases are notifiable and are often reported despite high estimated immunization coverage. The serological assessment of immunity against these infections (serosurveillance) complements disease surveillance (notification). This study aimed to assess the yet unmeasured serological immunities to nine vaccine-preventable infections among vaccinated Emirati children.

METHODS

This cross-sectional study involved children who attended the Well-Child Care Programme of the Ambulatory Healthcare Services (Al-Ain, UAE) between July 2014 and September 2015. Serological testing was performed in 227 Emirati children (49% females); subjects were aged (mean±standard deviation) 45±14 months (median 43, range 23-71 months).

RESULTS

The seroprevalence rates varied markedly among the studied vaccine-preventable diseases, ranging from 39.2% (pertussis) to 98.3% (rubella). Other high seroprevalence rates were noted for measles (98.2%) and poliovirus (92%). The seroprevalence rate for mumps was 82.8%, for varicella was 68.3%, for diphtheria was 86.4%, for tetanus was 89.9%, and for Haemophilus influenzae type B was 84.1%.

CONCLUSIONS

A large number of the studied children had low seroprevalence rates against pertussis, varicella, and mumps. Studies are needed to explore whether modifying the national immunization programme could improve these low seroprevalence estimates.

Characteristics of a large mumps outbreak: Clinical severity, complications and association with vaccination status of mumps outbreak cases

In recent years, large mumps outbreaks, involving mainly adolescents and young adults, have re-emerged in several countries. We investigated a large mumps outbreak, evaluated the association between mumps clinical severity (complications, hospitalization) and vaccination status (number of previous measles, mumps and rubella - MMR vaccine doses), and assessed vaccine effectiveness. The first mumps cases emerged in an ultra-orthodox boys' school in Jerusalem and were epidemiologically linked to the mumps outbreak in New York. Overall, 3130 mumps cases were notified in the Jerusalem district during September 2009-August 2011 (median age 13y, 64% males). Most cases were reported from community clinics. Patients with systemic symptoms and/or complications (419, 13.4%) were either hospitalized (n = 79) or treated in an emergency medical center (n = 340). The main complications included orchitis (3.8% males> age 12y) and meningoencephalitis (0.5%). The mumps virus genotype was G5. The distribution of previous MMR vaccine doses (n = 0,1,2) was: 24.8%, 28.3% and 46.9%, respectively. The number of previous vaccine doses was inversely associated with clinical severity. Adjusted values for MMR vaccine effectiveness against complications were estimated as 52.1% (95% CI -4 -78%) for one vaccine dose and 62.7% (95% CI 25.7-81.3%) for 2 doses. The outbreak was characterized by predominance of male students; the majority of whom had been previously vaccinated. The reported complication rate was relatively low. Vaccination status was associated with age and disease severity. The combination of limited mumps vaccine effectiveness and the specific school setting (dense learning and living conditions) probably contributed to the disease spread.

Application of Oral Fluid Assays in Support of Mumps, Rubella and Varicella Control Programs

Detection of specific viral antibody or nucleic acid produced by infection or immunization, using oral fluid samples, offers increased potential for wider population uptake compared to blood sampling. This methodology is well established for the control of HIV and measles infections, but can also be applied to the control of other vaccine preventable infections, and this review describes the application of oral fluid assays in support of mumps, rubella and varicella national immunization programs. In England and Wales individuals with suspected mumps or rubella, based on clinical presentation, can have an oral fluid swab sample taken for case confirmation. Universal varicella immunization of children has led to a drastic reduction of chickenpox in those countries where it is used; however, in England and Wales such a policy has not been instigated. Consequently, in England and Wales most children have had chickenpox by age 10 years; however, small, but significant, numbers of adults remain susceptible. Targeted varicella zoster virus (VZV) immunization of susceptible adolescents offers the potential to reduce the pool of susceptible adults and oral fluid determination of VZV immunity in adolescents is a potential means of identifying susceptible individuals in need of VZV vaccination. The main application of oral fluid testing is in those circumstances where blood sampling is deemed not necessary, or is undesirable, and when the documented sensitivity and specificity of the oral fluid assay methodology to be used is considered sufficient for the purpose intended.

Mumps outbreaks in a highly vaccinated population: Investigation of a neutralization titre against the current circulating wildtype genotype G5 mumps virus

BACKGROUND

Mumps outbreaks continue to occur globally, despite high levels of uptake of the mumps vaccine.

OBJECTIVES

In order to address immunity to the current circulating wildtype virus, we sought to determine a mumps G5 specific IgG quantitative value which correlates with genotype G5 specific neutralization ability in vitro.

STUDY DESIGN

Sera from 199 individuals including controls and acute mumps cases were assessed for mumps specific IgG titres using five different enzyme immunoassays coated with antigen from different mumps virus strains. A subset of 66 sera was also assessed for in vitro neutralizing antibody against a contemporary circulating genotype G5 mumps virus.

RESULTS

For all the different antigenic targets, mumps specific IgG titres were higher in patients following acute mumps infection compared to controls. In acute mumps infected patients, females showed significantly higher serum titres of anti-G5 IgG compared to males (p<0.05). Furthermore, control males did not show any change in G5 specific IgG with increasing age whereas females show a progressive rise in titre. Linear regression analysis revealed a significant association between the mumps G5 specific IgG levels in the EIA and the in vitro neutralization titres (r(2)=0.59).

CONCLUSIONS

Specific IgG to the current circulating genotype G5 mumps strain showed significantly lower titres in males which supports our previous observation that there is a male gender bias in cases of acute mumps infection. Furthermore, in this preliminary study, the data indicate that genotype G5 specific IgG levels of >40 RU/ml are required for neutralization capability to be observed in vitro.

Susceptibility to measles, mumps, and rubella in 5-year-old children in Flanders, Belgium

The second dose of an MMR vaccine is a catch up for persons who did not receive the first dose or for primary vaccine failures. Catch up doses can be scheduled according to convenience into the program of the country. The second MMR dose is often administered at the age of 5 years, before school entry. Some countries chose to implement the second dose at the age of 10-13 years, as is the case for Belgium. The here presented long-term follow-up of a cohort of children, set up originally to analyze maternal antibodies against vaccine preventable diseases, offers a unique opportunity to evaluate ad interim the current long-interval MMR vaccination schedule in Belgium. After 1 MMR dose at 12 months of age, rubella immunity is almost intact at 5 years of age (94.5 % is seropositive), measles seropositivity scores 86.8 %, and mumps 32 %, measured with ELISA. A seroneutralization (SN) test for mumps antibodies reveals much higher seropositivity rates (88 %). Using a regression model on the log (IgG) titer for all antigens, no influence was found from any of the studied variables, except for girls who had a significantly higher rubella IgG titer (p=0.002) compared to boys.

CONCLUSION

The data show considerable susceptibility to mumps and measles in 5-year-old children, confirming a previously conducted seroprevalence study (2006). Both advantages and disadvantages of shortening or enlarging the vaccine schedule are discussed.

Epidemiologic features of mumps in Taiwan from 2006 to 2011: a new challenge for public health policy

BACKGROUND

The adoption of a second dose of the measles-mumps-rubella (MMR) vaccine among Taiwanese school children began in 2001. However, during that time, mumps cases continued to occur. The purpose of the present study was to assess the epidemiology and vaccination policy for mumps in Taiwan.

METHODS

We examined the data on mumps cases collected by the Taiwan Centers for Disease Control (Taiwan CDC) between 2006 and 2011.

RESULTS

During the 6-year study period, a total of 6612 cases of mumps were reported to the Taiwan CDC. Of the patients with known vaccination status, 62% received one dose of the MMR vaccine or no vaccine. The incidence of mumps ranged from 4.18 to 5.28 per 100 000 population and peaked in 2007. Males had a higher incidence of mumps than females (5.9 vs. 3.7 per 100 000 population; P=0.024). Children between 5 and 6 years of age had the highest incidence of mumps, and those 20 years and older had the lowest incidence. Compared to those who received two doses of the MMR vaccine, patients who were not vaccinated or received a single dose of the vaccine had a higher risk of suffering from complications and/or hospitalization.

CONCLUSIONS

In Taiwan, more than 60% of mumps cases received either no dose or one dose of the MMR vaccine. Monitoring mumps through biological testing and instituting a second dose of the MMR vaccine for children is needed for the elimination of mumps in Taiwan.

Estimating seroprevalence of vaccine-preventable infections: is it worth standardizing the serological outcomes to adjust for different assays and laboratories?

The aim of the European Sero-Epidemiology Network 2 (ESEN2) project was to estimate age-specific seroprevalence for a number of vaccine-preventable diseases in Europe. To achieve this serosurveys were collected by 22 national laboratories. To adjust for a variety of laboratory methods and assays, all quantitative results were transformed to a reference laboratory's units and were then classified as positive or negative to obtain age-specific seroprevalence. The aim of this study was to assess the value of standardization by comparing the crude and standardized seroprevalence estimates. Seroprevalence was estimated for measles, mumps, rubella, diphtheria, varicella zoster and hepatitis A virus (HAV) and compared before and after serological results had been standardized. The results showed that if no such adjustment had taken place, seroprevalence would have differed by an average of 3·2% (95% bootstrap interval 2·9-3·6) although this percentage varied substantially by antigen. These differences were as high as 16% for some serosurveys (HAV) which means that standardization could have a considerable impact on seroprevalence estimates and should be considered when comparing serosurveys performed in different laboratories using different assay methods.

Viral etiology of mumps-like illnesses in suspected mumps cases reported in Catalonia, Spain

We investigated the etiology of reported sporadic suspected mumps cases with a negative RT-PCR result for the mumps virus in the Barcelona-South region in 2007-2011. Samples from mumps virus-negative patients presenting unilateral or bilateral parotitis or other salivary gland swelling were tested for Epstein-Barr virus (EBV) by real-time PCR and for respiratory viruses by two multiplex-PCR-based assays to detect parainfluenza virus (PIV) 1-4, influenza virus (InV) A, B and C, respiratory syncytial virus (RSV), enterovirus, coronavirus 229E, coronavirus OC43, and rhinovirus. 101 samples were analyzed in persons aged 8 months to 50 years. Oral samples were collected on the first day of glandular swelling in 53 patients (52.5%), and on the first two days in 74 patients (73.3%). Viruses were detected in 52 (51.5%) of samples: one virus (25 EBV, 8 PIV3, 4 adenovirus, 4 PIV2, 1 PIV1, 1 InVA, and 1 enterovirus) was detected in 44 patients (84.6%), two viruses in 7 patients, and three viruses in one patient. In 58 patients (57.5%) whose sample was collected in the first 2 days after onset of parotitis and had received two doses of MMR vaccine and in 15 patients (14.8%) whose sample was collected on the first day, it is very likely that the cause was not the mumps virus. This would mean that 72.3% (73/101) of the reported sporadic suspected mumps cases were not mumps cases. The timing of oral-sample collection is crucial to correctly interpret the negative results for mumps virus RNA, especially when suspected cases occur in vaccinated persons.

Mumps outbreak in the Federation of Bosnia and Herzegovina with large cohorts of susceptibles and genetically diverse strains of genotype G, Bosnia and Herzegovina, December 2010 to September 2012

A mumps outbreak reported from the Federation of Bosnia and Herzegovina involved 7,895 cases between December 2010 and September 2012. This was the largest outbreak in the country since the introduction of the measles, mumps and rubella vaccine in 1980. The highest disease incidence was found among 15 to 19 year-olds. About 39% (3,050/7,895) of cases reported to be unvaccinated; the vaccination status of 31% (2,426/7,895) was unknown. A seroprevalence study among 150 asymptomatic contacts to mumps cases showed that about one third (45/150) were susceptible to mumps. Among 105 clinically suspected mumps patients hospitalised at the Clinical Centre of the University of Sarajevo, orchitis (60% of all males: 51/85) and meningitis (9%: 9/105) were the most common complications. Among 57 outbreak sequences obtained for the small hydrophobic gene, eight different variants of genotype G viruses were identified. The outbreak affected mainly age groups comprising individuals who were not vaccinated during or after the Bosnian war, as well as cantons with single dose immunisation policies until 2001. In addition to issues related to vaccination of individuals, differential responses to vaccines and vaccine strains, waning of antibodies and potentially also the genetically diverse variants of genotype G may have compounded the size and duration of the outbreak. Our report emphasizes the need for supplementary immunisation programmes in particular for adolescents and young adults.

Assessing mumps outbreak risk in highly vaccinated populations using spatial seroprevalence data

Mumps is a potentially severe viral infection. The incidence of mumps has declined dramatically in high-income countries since the introduction of mumps antigen-containing vaccines. However, recent large outbreaks of mumps in highly vaccinated populations suggest waning of vaccine-induced immunity and primary vaccine failure. In this paper we present a simple method for identifying geographic regions with high outbreak potential, demonstrated using 2006 mumps seroprevalence data from Belgium and Belgian vaccination coverage data. Predictions of the outbreak potential in terms of the effective reproduction number in future years signal an increased risk of new mumps outbreaks. Literature reviews on serological information for both primary vaccine failure and waning immunity provide essential information for our predictions. Tailor-made additional vaccination campaigns would be valuable for decreasing local pockets of susceptibility, thereby reducing the risk of future large-scale mumps outbreaks.

Underreporting of viral encephalitis and viral meningitis, Ireland, 2005-2008

Viral encephalitis (VE) and viral meningitis (VM) have been notifiable infectious diseases under surveillance in the Republic of Ireland since 1981. Laboratories have reported confirmed cases by detection of viral nucleic acid in cerebrospinal fluid since 2004. To determine the prevalence of these diseases in Ireland during 2005–2008, we analyzed 3 data sources: Hospital In-patient Enquiry data (from hospitalized following patients discharge) accessed through Health Intelligence Ireland, laboratory confirmations from the National Virus Reference Laboratory, and events from the Computerised Infectious Disease Reporting surveillance system. We found that the national surveillance system underestimates the incidence of these diseases in Ireland with a 10-fold higher VE hospitalization rate and 3-fold higher VM hospitalization rate than the reporting rate. Herpesviruses were responsible for most specified VE and enteroviruses for most specified VM from all 3 sources. Recommendations from this study have been implemented to improve the surveillance of these diseases in Ireland.

Epidemiology and the economic assessment of a mumps outbreak in a highly vaccinated population, Orange County, New York, 2009-2010

Studies assessing the economic burden of a mumps outbreak in a highly vaccinated population are limited. The Orange County Health Department (OCHD), New York State Department of Health (NYS DOH), and the Centers for Disease Control and Prevention conducted a mumps investigation in an affected village with a highly vaccinated population. To understand the epidemiology, standardized mumps case definition and active surveillance were used to identify mumps cases. In addition, an economic assessment of a combined outbreak investigation and third dose measles-mumps-rubella (MMR) vaccine intervention conducted by OCHD and NYS DOH was performed; estimated by retrospectively evaluating public health response-related activities including use of a third dose of MMR vaccine. From September 24, 2009, through June 15, 2010, 790 mumps cases were reported-64% were male and highest attack rate was among 11-17 year age group (99.1 cases per 1000 individuals). Of the 658 cases with known vaccination history, 83.6% had documentation of 2 doses of mumps containing vaccine. No deaths were reported. The 2 major exposure settings were schools (71.8%) and households (22.5%). Approximately 7736 h of public health personnel time were expended with the total approximate cost of US $463,000, including US $34,392 for MMR vaccine-the estimated cost per household was US $827. Mumps continues to be endemic in many parts of the world, resulting in importations into the United States. Large mumps outbreaks similar to this in highly vaccinated populations may require considerable investigation and control activities.

Estimates of mumps seroprevalence may be influenced by antibody specificity and serologic method

Neutralizing antibodies are assumed to be essential for protection against mumps virus infection, but their measurement is labor- and time-intensive. For this reason, enzyme-linked immunosorbent assays (ELISAs) are typically used to measure mumps-specific IgG levels. However, since there is poor correlation between mumps neutralization titers and ELISAs that measure the presence of mumps-specific IgG levels, ELISAs that better correlate with neutralization are needed. To address this issue, we measured mumps antibody levels by plaque reduction neutralization, by a commercial ELISA (whole-virus antigen), and by ELISAs specific for the mumps nucleoprotein and hemagglutinin. The results indicate that differences in the antibody response to the individual mumps proteins could partially explain the lack of correlation among various serologic tests. Furthermore, the data indicate that some seropositive individuals have low levels of neutralizing antibody. If neutralizing antibody is important for protection, this suggests that previous estimates of immunity based on whole-virus ELISAs may be overstated.

Point-of-care syndrome-based, rapid diagnosis of infections on commercial ships

BACKGROUND

Suspicion of contagious disease on commercial ships tends to be poorly managed, as there is little capacity to confirm a case on board except for malaria. Here we implemented a point-of-care (POC) laboratory on one container ship and one cruise ship for the rapid syndrome-based diagnosis of infectious diseases on board.

METHODS

In 2012 we implemented a POC laboratory on board a freight ship and on board a cruise ship. The POC laboratory ran a total of six different color-coded, syndrome-based kits incorporating 10 different commercially available immunochromatographic tests. The POC tests were taught within 1-hour as part of training to staff without any previous knowledge in microbiology.

RESULTS

Compared with terrestrial POCs, specific constraints included the necessity to secure POC devices into the motile ship, to use robust devices, to overcome difficulties in communicating with the core laboratory, and to overcome limited intimacy of patients. However, a total of 36 POC tests were easily performed and yielded contributive negative results.

CONCLUSIONS

This first experiment indicates that it is possible to run POC laboratories by nonexpert staff after providing rapid teaching course on board commercial ships. Generalization of on-board POC laboratories is expected to help in improving the medical management of staff and passengers.

Are cases of mumps in vaccinated patients attributable to mismatches in both vaccine T-cell and B-cell epitopes?: An immunoinformatic analysis

Resurgent mumps outbreaks have raised questions about the current efficacy of mumps vaccines. We have applied immunoinformatics techniques based on principal component analysis to evaluate patterns in predicted B-cell linear epitopes, MHC binding affinity and cathepsin cleavage in the hemagglutinin neuraminidase protein of vaccine strains and wild-type mumps isolates. We have mapped predicted MHC-peptide binding for 37 MHC-I and 28 MHC-II alleles and predicted cleavage by cathepsin B, L and S. By all measures we applied Jeryl-Lynn JL5 major strain is an outlier with immunomic features arising from a small number of amino acid changes that distinguish it from other virus strains. Individuals vaccinated with Jeryl-Lynn who are not exposed to wild-type virus until their protective antibody titer has waned may be unable to recall a protective immune response when exposed to wild-type virus. Dependence on serology to evaluate mumps vaccines may have overemphasized the conservation of one neutralizing antibody epitope, at the expense of monitoring other related changes in the HN protein that could affect recall responses.

Outbreak-related mumps vaccine effectiveness among a cohort of children and of young adults in Germany 2011

Mumps outbreaks in populations with high 2-dose vaccination coverage and among young adults are increasingly reported. However, data on the duration of vaccine-induced protection conferred by mumps vaccines are scarce. As part of a supra-regional outbreak in Germany 2010/11, we conducted two retrospective cohort studies in a primary school and among adult ice hockey teams to determine mumps vaccine effectiveness (VE). Via questionnaires we collected information on demography, clinical manifestations, and reviewed vaccination cards. We estimated VE as 1-RR, RR being the rate ratio of disease among two-times or one-time mumps-vaccinated compared with unvaccinated persons. The response rate was 92.6% (100/108--children cohort) and 91.7% (44/48--adult cohort). Fourteen cases were identified in the children and 6 in the adult cohort. In the children cohort (mean age: 9 y), 2-dose VE was 91.9% (95% CI 81.0-96.5%). In the adult cohort (mean age: 26 y), no cases occurred among the 13 2-times vaccinated, while 1-dose VE was 50.0% (95% CI -9.4-87.1%). Average time since last vaccination showed no significant difference for cases and non-cases, but cases were younger at age of last mumps vaccination (children cohort: 2 vs. 3 y, P=0.04; adult cohort: 1 vs. 4 y, P=0.03). We did not observe signs of waning immunity in the children cohort. Due to the small sample size VE in the adult cohort should be interpreted with caution. Given the estimated VE, very high 2-dose vaccination coverage is required to prevent future outbreaks. Intervention efforts to increase coverage must especially target young adults who received<2 vaccinations during childhood.

Mumps epidemiology in Germany 2007-11

In Germany, mumps has been notifiable until 2013 only in the five Eastern federal states (EFS) of former East Germany. Due to different immunisation policies until 1990 and varying vaccination coverages thereafter, mumps incidences cannot be extrapolated to the 11 Western federal states (WFS). We studied mumps-related International Classification of Diseases (ICD-10) code diagnoses claimed through statutory health insurances between 2007 and 2011 to estimate countrywide mumps incidences in the outpatient sector, and compared them with case numbers from ambulatory notification data. Overall, 32,330 outpatient mumps cases were claimed. Annual incidence ranged between 9.3/100,000 and 11.8/100,000 and showed a significant decreasing trend. Compared with EFS, mumps incidence in WFS was higher and indicated a shift towards older age groups. Notified outpatient case numbers in EFS were 13-fold lower and from voluntary surveillance during an outbreak in the WFS Bavaria 8-fold lower than from insurance data (n=316 versus n=4,217 and n=238 versus 1,995, respectively). Of all notified cases with available information, 75.4% (EFS) and 57.6% (Bavaria) were unvaccinated; 6.8% (EFS) and 19.3% (Bavaria) required hospitalisation. In Germany, mumps is still endemic despite decades of vaccination, with considerable underreporting in the established notification systems.

Seroprevalence of antibodies against measles, rubella, mumps, varicella-zoster, and B. Pertussis in young adults of Madrid, Spain

In recent years, there has been an increase in the number of cases of certain immunopreventable diseases in our country. A high proportion of these have been recorded among the young adult population. The aim of this study was to determine the seroprevalence of antibodies against immunopreventable diseases with the greatest health impacts on the young adult population (19-39 y of age) in Madrid. We collected a total of 1,153 serum samples from healthy volunteers undergoing routine medical visits and used ELISA to determine the presence of IgG antibodies against measles, rubella, mumps, and varicella zoster, as well as Bordetella pertussis. The Pearson's χ(2) test was used to compare prevalences, the Mann-Whitney U test was used to compare means, and the Kruskal-Wallis test was applied for variables with more than 2 categories. Statistical significance was achieved with p values of<0.05. The global prevalence of antibodies was 92.1% for measles, 94.4% for rubella, 88.3% for mumps, 92.8% for varicella zoster, and 70.2% for B. pertussis. No statistically significant differences were found between genders. The prevalence of antibodies against measles was more than 95% in the group of individuals born after 1986, and the percentage of individuals susceptible to rubella was less than 5% in women born after 1986. In spite of adequate vaccination coverage, in our region, a population of young adults exists who have not achieved the objectives of the WHO for the elimination of measles and congenital rubella syndrome.

Environmental factors potentially associated with mumps transmission in yeshivas during a mumps outbreak among highly vaccinated students: Brooklyn, New York, 2009-2010

During 2009-2010, a large US mumps outbreak occurred affecting two-dose vaccinated 9th-12th grade Orthodox Jewish boys attending all-male yeshivas (private, traditional Jewish schools). Our objective was to understand mumps transmission dynamics in this well-vaccinated population. We surveyed 9th-12th grade male yeshivas in Brooklyn, NY with reported mumps case-students between 9/1/2009 and 3/30/2010. We assessed vaccination coverage, yeshiva environmental factors (duration of school day, density, mixing, duration of contact), and whether environmental factors were associated with increased mumps attack rates. Ten yeshivas comprising 1769 9th-12th grade students and 264 self-reported mumps cases were included. The average yeshiva attack rate was 14.5% (median: 13.5%, range: 1-31%), despite two-dose measles-mumps-rubella vaccine coverage between 90-100%. School duration was 9-15.5 h/day; students averaged 7 h face-to-face/day with 1-4 study partners. Average daily mean density was 6.6 students per 100 square feet. The number of hours spent face-to-face with a study partner and the number of partners per day showed significant positive associations (p < 0.05) with classroom mumps attack rates in univariate analysis, but these associations did not persist in multivariate analysis. This outbreak was characterized by environmental factors unique to the yeshiva setting (e.g., densely populated environment, prolonged face-to-face contact, mixing among infected students). However, these features were present in all included yeshivas, limiting our ability to discriminate differences. Nonetheless, mumps transmission requires close contact, and these environmental factors may have overwhelmed vaccine-mediated protection increasing the likelihood of vaccine failure among yeshiva students.

Mumps: burden of disease in France

This article provides a review of the epidemiological data on mumps in France since 1986. The results of 26 years of monitoring in general practice by the Sentinel network are analysed, such as hospitalisation data between 2004 and 2010, as well as mortality data between 2000 and 2009. The annual incidence rate has plummeted between 1986 and 2011, from 859 cases per 100,000 inhabitants [95% CI: 798-920] to 9 cases per 100,000 inhabitants [95% CI: 4-14]. A change in the age distribution is significant with an increase of Relative Illness Ratio (RIR) for patients over 20 years. Since 2000, vaccine status has also changed, and the majority of recent mumps cases occur among previously vaccinated patients. The average annual hospitalisation rate is 3.2 per 1 million inhabitants. Mumps was identified as the initial cause of death in 1 case every 5 years. This study estimates the burden of mumps disease in France.