Mumps outbreak among vaccinated university students associated with a large party, the Netherlands, 2010

Measles, mumps, rubella and varicella antibodies among international and domestic university students

BACKGROUND

Vaccine-preventable infections are generally well controlled in Australia. However, gaps in immunity can lead to outbreaks and are important to identify. Young adults are a highly mobile population and a potential source of imported infections. We aimed to evaluate anti- measles, mumps, rubella and varicella (MMR&V) IgG seroprevalence and explore factors relating to antibody seropositivity.

METHODS

A cross-sectional online survey was conducted among students from a large Australian university to collect demographic, vaccination, infection and travel characteristics. Blood samples were collected to measure MMR&V seroprevalence. Logistic regression was used to identify factors associated with seropositivity.

RESULTS

Among 804 university students, seroprevalence (positive or equivocal) for measles was 82.3% (95% CI 79.6-84.8%), mumps 79.5% (95% CI 76.7-82.3%), rubella 91.5% (95% CI 89.6-93.5%) and varicella 86.2% (95% CI 84.1-88.8%), with 452 (56.2%, 95% CI 52.8-59.6) seropositive to all four viruses. Varicella seropositivity was highest in the older birth cohort (born 1988-1991). Measles seropositivity was higher for international students compared to domestic students. Among international students, mumps seroprevalence was significantly lower than measles and rubella seroprevalence. International travel in the previous 12 months was reported by 63.1% of students, but only 18.2% of travellers reported seeking pre-travel health advice prior to most recent international travel.

CONCLUSIONS

Overall, this study suggests immunity to MMR&V is sub-optimal. We found the university student population to be highly mobile and unlikely to seek pre-travel advice; thus, they are a potential source of infection importation. The implementation of university immunization policies could address the gaps identified and our findings can inform the development of targeted vaccination campaigns.

Comparison of circulation patterns of mumps virus in the Netherlands and Spain (2015-2020)

Background

Mumps is a viral infection mainly characterized by inflammation of the parotid glands. Despite of vaccination programs, infections among fully vaccinated populations were reported. The World Health Organization (WHO) recommends molecular surveillance of mumps based on sequencing of the small hydrophobic (SH) gene. The use of hypervariable non-coding regions (NCR) as additional molecular markers was proposed in multiple studies. Circulation of mumps virus (MuV) genotypes and variants in different European countries were described in the literature. From 2010 to 2020, mumps outbreaks caused by genotype G were described. However, this issue has not been analyzed from a wider geographical perspective. In the present study, sequence data from MuV detected in Spain and in The Netherlands during a period of 5  years (2015- March 2020) were analyzed to gain insights in the spatiotemporal spread of MuV at a larger geographical scale than in previous local studies.

Methods

A total of 1,121 SH and 262 NCR between the Matrix and Fusion protein genes (MF-NCR) sequences from both countries were included in this study. Analysis of SH revealed 106 different haplotypes (set of identical sequences).

Results

Of them, seven showing extensive circulation were considered variants. All seven were detected in both countries in coincident temporal periods. A single MF-NCR haplotype was detected in 156 sequences (59.3% of total), and was shared by five of the seven SH variants, as well as three minor MF-NCR haplotypes. All SH variants and MF-NCR haplotypes shared by both countries were detected first in Spain.

Discussion

Our results suggest a transmission way from south to north Europe. The higher incidence rate of mumps in Spain in spite of similar immunization coverage in both countries, could be associated with higher risk of MuV exportation. In conclusion, the present study provided novel insights into the circulation of MuV variants and haplotypes beyond the borders of single countries. In fact, the use of MF-NCR molecular tool allowed to reveal MuV transmission flows between The Netherlands and Spain. Similar studies including other (European) countries are needed to provide a broader view of the data presented in this study.

Mumps serological surveillance following 10 years of a one-dose mumps-containing-vaccine policy in Fujian Province, China

BACKGROUND

Since 2008, Fujian province provided measles-rubella (MR) vaccine at 8 months followed by measles-mumps-rubella (MMR) vaccine at 18 months a one-dose mumps-containing-vaccine (MuCV) schedule. Several mumps outbreaks have occurred recently in Fujian. Serological surveillance can assess population immunity to mumps and identify risk factors for mumps.

METHODS

We conducted a cross-sectional serosurvey of mumps IgG antibodies in the general population of Fujian Province in 2018 and compare results with a similar study conducted in 2009, when the routine schedule had no MuCV. We analyzed changes in mumps epidemiology after implementation of a one-dose MuCV vaccination strategy.

RESULTS

Mumps seroprevalence was 78.6% (95% CI: 77.4-79.8), and the geometric mean concentration (GMC) of mumps antibodies was 245.8 IU/ml (95% CI:237.3-255.1). MuCV vaccination at 18 months resulted in increased seroprevalence and GMCs. Seroprevalence and GMCs varied by age, gender, and number of doses received. Except for children under 18 months, seroprevalence and GMCs were lowest among 10-15-year-olds. Each year after introduction of the one-dose MuCV vaccination policy, the highest incidence of mumps was among 4-6-year-olds and 9-15-year-olds, gradually shifting to older age groups.

CONCLUSION

A one-dose mumps-containing vaccine schedule does not provide sustained and stable mumps immunity in Fujian. To reduce the risk of mumps, we recommend supplementary vaccination of children without a history of receiving at least one MuCV dose or who are seronegative at 10-15 years of age.

Impact of vaccine effectiveness and coverage on preventing large mumps outbreaks on college campuses: Implications for vaccination strategy

Recent mumps outbreaks among highly vaccinated populations, including college students, have called into question the vaccine effectiveness (VE) of routine two-dose measles, mumps, and rubella (MMR2) immunization. We aimed to estimate the VE required for a novel vaccination strategy (e.g., MMR booster dose, novel vaccine) to prevent large mumps outbreaks on college campuses. Using mumps college outbreak data reported to the U.S. Centers for Disease Control and Prevention during 2016-2017, we estimated current MMR2 VE using the screening method and implemented a compartmental model of mumps transmission. We performed 2000 outbreak simulations, following introduction of an infectious person to a population of 10,000, over ranges of MMR2 vaccine coverage (VC) and VE (30.0-99.0%). We compared the impact of varying VC and VE on mumps and mumps orchitis case counts and determined VE thresholds that ensured < 5.0% and < 2.0% of the outbreak simulations exceeded 20 and 100 mumps cases. Median estimated MMR2 VE in reported mumps outbreaks was 60.5% and median reported MMR2 VC was 97.5%. Simulated mumps case count was more sensitive to changes in VE than in VC. The opposite was true for simulated mumps orchitis case count, though orchitis case count was small (mean <10 cases across simulations for VE near 60.5% and VC near 97.5%). At 97.5% VC, 73.1% and 78.2% VE were required for < 5.0% and < 2.0% of outbreaks, respectively, to exceed 100 mumps cases. Maintaining 97.5% VC, 82.4% and 85.9% VE were required for < 5.0% and < 2.0% of outbreaks, respectively, to exceed 20 cases. We conclude that maintaining current levels of MMR2 VC, a novel vaccination strategy aimed at reducing mumps transmission must achieve at least 73.1-85.9% VE among young adults to prevent large mumps outbreaks on college campuses.

Online survey of university students' perception, awareness and adherence to COVID-19 prevention measures

BACKGROUND

Determining factors correlated with protective measures against COVID-19 is important to improve public health response. This study describes student opinions related to university COVID-19 preventive measures.

METHODS

In fall 2020, 643 US university students completed an online survey on perception, awareness, and adherence to COVID-19 preventive measures. Outcomes included protocol effectiveness (self or others), protocol adherence (self or others), consequences of protocol violation, knowledge of violations, and level of concern for COVID-19. Multiple linear regression models determined correlates of outcome variables. Covariates included gender, race, residence, area of study, class, and knowledge of someone with a positive COVID-19 test.

RESULTS

Overall, students agreed with protective measures (equivalent to higher scores). In adjusted linear models, females (versus males) had significantly higher scores for protocol effectiveness (self) (p < 0.001), consequences of protocol violation (p = 0.005), and concern about COVID-19 (p < 0.001). Asian/Pacific Islander (versus white) had significantly higher scores for protocol effectiveness (self) (p < 0.001), consequences of protocol violation (p = 0.008), and concern about COVID-19 (p = 0.001). Graduate students (versus freshman) had higher scores for protocol effectiveness (self) (p < 0.001), protocol adherence (self) (p = 0.004) and concern about COVID-19 (p < 0.001). In contrast, participants who had a positive COVID-19 test had significantly lower scores for protocol effectiveness (self) (p = 0.02), protocol adherence (self) (p = 0.004), and consequences of protocol violation (p = 0.008).

CONCLUSION

Overall, females, Asian/Pacific Islanders, and graduate students were more likely to agree with or adhere to COVID-19 prevention guidelines but those who tested positive for COVID-19 were less likely to do so. These results may inform future prevention efforts.

Vaccines for measles, mumps, rubella, and varicella in children

BACKGROUND

Measles, mumps, rubella, and varicella (chickenpox) are serious diseases that can lead to serious complications, disability, and death. However, public debate over the safety of the trivalent MMR vaccine and the resultant drop in vaccination coverage in several countries persists, despite its almost universal use and accepted effectiveness. This is an update of a review published in 2005 and updated in 2012.

OBJECTIVES

To assess the effectiveness, safety, and long- and short-term adverse effects associated with the trivalent vaccine, containing measles, rubella, mumps strains (MMR), or concurrent administration of MMR vaccine and varicella vaccine (MMR+V), or tetravalent vaccine containing measles, rubella, mumps, and varicella strains (MMRV), given to children aged up to 15 years.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (the Cochrane Library 2019, Issue 5), which includes the Cochrane Acute Respiratory Infections Group's Specialised Register, MEDLINE (1966 to 2 May 2019), Embase (1974 to 2 May 2019), the WHO International Clinical Trials Registry Platform (2 May 2019), and ClinicalTrials.gov (2 May 2019).

SELECTION CRITERIA

We included randomised controlled trials (RCTs), controlled clinical trials (CCTs), prospective and retrospective cohort studies (PCS/RCS), case-control studies (CCS), interrupted time-series (ITS) studies, case cross-over (CCO) studies, case-only ecological method (COEM) studies, self-controlled case series (SCCS) studies, person-time cohort (PTC) studies, and case-coverage design/screening methods (CCD/SM) studies, assessing any combined MMR or MMRV / MMR+V vaccine given in any dose, preparation or time schedule compared with no intervention or placebo, on healthy children up to 15 years of age.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data and assessed the methodological quality of the included studies. We grouped studies for quantitative analysis according to study design, vaccine type (MMR, MMRV, MMR+V), virus strain, and study settings. Outcomes of interest were cases of measles, mumps, rubella, and varicella, and harms. Certainty of evidence of was rated using GRADE.

MAIN RESULTS

We included 138 studies (23,480,668 participants). Fifty-one studies (10,248,159 children) assessed vaccine effectiveness and 87 studies (13,232,509 children) assessed the association between vaccines and a variety of harms. We included 74 new studies to this 2019 version of the review. Effectiveness Vaccine effectiveness in preventing measles was 95% after one dose (relative risk (RR) 0.05, 95% CI 0.02 to 0.13; 7 cohort studies; 12,039 children; moderate certainty evidence) and 96% after two doses (RR 0.04, 95% CI 0.01 to 0.28; 5 cohort studies; 21,604 children; moderate certainty evidence). The effectiveness in preventing cases among household contacts or preventing transmission to others the children were in contact with after one dose was 81% (RR 0.19, 95% CI 0.04 to 0.89; 3 cohort studies; 151 children; low certainty evidence), after two doses 85% (RR 0.15, 95% CI 0.03 to 0.75; 3 cohort studies; 378 children; low certainty evidence), and after three doses was 96% (RR 0.04, 95% CI 0.01 to 0.23; 2 cohort studies; 151 children; low certainty evidence). The effectiveness (at least one dose) in preventing measles after exposure (post-exposure prophylaxis) was 74% (RR 0.26, 95% CI 0.14 to 0.50; 2 cohort studies; 283 children; low certainty evidence). The effectiveness of Jeryl Lynn containing MMR vaccine in preventing mumps was 72% after one dose (RR 0.24, 95% CI 0.08 to 0.76; 6 cohort studies; 9915 children; moderate certainty evidence), 86% after two doses (RR 0.12, 95% CI 0.04 to 0.35; 5 cohort studies; 7792 children; moderate certainty evidence). Effectiveness in preventing cases among household contacts was 74% (RR 0.26, 95% CI 0.13 to 0.49; 3 cohort studies; 1036 children; moderate certainty evidence).  Vaccine effectiveness against rubella, using a vaccine with the BRD2 strain which is only used in China, is 89% (RR 0.11, 95% CI 0.03 to 0.42; 1 cohort study; 1621 children; moderate certainty evidence).  Vaccine effectiveness against varicella (any severity) after two doses in children aged 11 to 22 months is 95% in a 10 years follow-up (rate ratio (rr) 0.05, 95% CI 0.03 to 0.08; 1 RCT; 2279 children; high certainty evidence). Safety There is evidence supporting an association between aseptic meningitis and MMR vaccines containing Urabe and Leningrad-Zagreb mumps strains, but no evidence supporting this association for MMR vaccines containing Jeryl Lynn mumps strains (rr 1.30, 95% CI 0.66 to 2.56; low certainty evidence). The analyses provide evidence supporting an association between MMR/MMR+V/MMRV vaccines (Jeryl Lynn strain) and febrile seizures. Febrile seizures normally occur in 2% to 4% of healthy children at least once before the age of 5. The attributable risk febrile seizures vaccine-induced is estimated to be from 1 per 1700 to 1 per 1150 administered doses. The analyses provide evidence supporting an association between MMR vaccination and idiopathic thrombocytopaenic purpura (ITP). However, the risk of ITP after vaccination is smaller than after natural infection with these viruses. Natural infection of ITP occur in 5 cases per 100,000 (1 case per 20,000) per year. The attributable risk is estimated about 1 case of ITP per 40,000 administered MMR doses. There is no evidence of an association between MMR immunisation and encephalitis or encephalopathy (rate ratio 0.90, 95% CI 0.50 to 1.61; 2 observational studies; 1,071,088 children; low certainty evidence), and autistic spectrum disorders (rate ratio 0.93, 95% CI 0.85 to 1.01; 2 observational studies; 1,194,764 children; moderate certainty). There is insufficient evidence to determine the association between MMR immunisation and inflammatory bowel disease (odds ratio 1.42, 95% CI 0.93 to 2.16; 3 observational studies; 409 cases and 1416 controls; moderate certainty evidence). Additionally, there is no evidence supporting an association between MMR immunisation and cognitive delay, type 1 diabetes, asthma, dermatitis/eczema, hay fever, leukaemia, multiple sclerosis, gait disturbance, and bacterial or viral infections.  AUTHORS' CONCLUSIONS: Existing evidence on the safety and effectiveness of MMR/MMRV vaccines support their use for mass immunisation. Campaigns aimed at global eradication should assess epidemiological and socioeconomic situations of the countries as well as the capacity to achieve high vaccination coverage. More evidence is needed to assess whether the protective effect of MMR/MMRV could wane with time since immunisation.

Outbreaks of mumps genotype G viruses in the Netherlands between October 2019 and March 2020: clusters associated with multiple introductions

Background

From October 2019–March 2020, several clusters of mumps cases were identified in the Netherlands. Our objective was to describe cluster-associated mumps virus transmission using epidemiological and molecular information in order to help future mumps outbreak investigation and control efforts.

Methods

An epidemiological cluster includes ≥ 2 mumps cases with at least an epidemiological-link to a laboratory-confirmed mumps case. A molecular group includes ≥ 2 mumps cases with identical mumps virus sequences. Cases with symptom onset date between 1 October 2019 and 31 March 2020 reported through the National Notifiable Diseases Surveillance System were included. We described epidemiological and clinical characteristics of mumps cases. Sequence data was obtained from selected regions of mumps virus genomes (2270 nucleotides). Associations between epidemiological and molecular information were investigated.

Results

In total, 102 mumps cases were notified (90% laboratory-confirmed, 10% epidemiologically-linked). 71 out of 102 cases were identified as part of an epidemiological cluster and/or molecular group. Twenty-one (30%) of 71 cases were identified solely from epidemiological information, 25 (35%) solely from molecular surveillance, and 25 (35%) using both. Fourteen epidemiological clusters were identified containing a total of 46 (range: 2–12, median: 3) cases. Complete sequence data was obtained from 50 mumps genotype G viruses. Twelve molecular groups were identified containing 43 (range: 2–13) cases, dispersed geographically and timewise. Combined information grouped seven epidemiological clusters into two distinct molecular groups. The first lasting for 14 weeks, the other for 6. Additionally, one molecular group was detected, linked by geography and time but without an epidemiological-link.

Conclusions

Combined epidemiological and molecular information indicated ongoing mumps virus transmission from multiple introductions for extended time periods. Sequence analysis provided valuable insights into epidemiological clustering. If combined information is available in a timely manner, this would improve outbreak detection, generate further insight into mumps transmission, and guide necessary control measures.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-021-06702-7.

Structural plasticity of mumps virus nucleocapsids with cryo-EM structures

Mumps virus (MuV) is a highly contagious human pathogen and frequently causes worldwide outbreaks despite available vaccines. Similar to other mononegaviruses such as Ebola and rabies, MuV uses a single-stranded negative-sense RNA as its genome, which is enwrapped by viral nucleoproteins into the helical nucleocapsid. The nucleocapsid acts as a scaffold for genome condensation and as a template for RNA replication and transcription. Conformational changes in the MuV nucleocapsid are required to switch between different activities, but the underlying mechanism remains elusive due to the absence of high-resolution structures. Here, we report two MuV nucleoprotein-RNA rings with 13 and 14 protomers, one stacked-ring filament and two nucleocapsids with distinct helical pitches, in dense and hyperdense states, at near-atomic resolutions using cryo-electron microscopy. Structural analysis of these in vitro assemblies indicates that the C-terminal tail of MuV nucleoprotein likely regulates the assembly of helical nucleocapsids, and the C-terminal arm may be relevant for the transition between the dense and hyperdense states of helical nucleocapsids. Our results provide the molecular mechanism for structural plasticity among different MuV nucleocapsids and create a possible link between structural plasticity and genome condensation.

Shan et al. describes the high-resolution structures of Nucleoprotein in two different oligomeric states and four different higher-order helical structures. They further describe the structural rearrangements required to transition between the different helical assemblies obtained, highlighting the basis for structural plasticity among different MuV nucleocapsids.

Development of a Haddon Matrix Framework for Higher Education Pandemic Preparedness: Scoping Review and Experiences of Malaysian Universities During the COVID-19 Pandemic

Managing education and research during pandemics has increased in importance since the onset of epidemics such as avian flu, SARS and now CoViD-19. Successful management in times of crisis ensures business continuity and institutional survival, making preparedness preceding an impending pandemic essential. Institutions of higher education (IHEs) must maintain balance between academic continuity and preventing morbidity during a pandemic crisis. To date, however, no general pandemic preparedness frameworks exist for IHEs. The aim of this paper is to report on the development of a Haddon matrix framework for IHE pandemic preparedness based on a scoping literature review of past IHE responses including pre-, during and post-pandemic phases. First, a review of previous global responses by IHEs during past pandemics was carried out. The review findings were then collated into a new IHE-centric Haddon matrix for pandemic preparedness. The content of the matrix is then illustrated through the documented responses of Malaysian universities during the early stages of the COVID-19 pandemic. The resulting IHE Haddon matrix can be used by universities as a general guide to identify preparedness gaps and intervention opportunities for business continuity during pandemics.

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.

A Third Dose of Measles-Mumps-Rubella Vaccine to Improve Immunity Against Mumps in Young Adults

BACKGROUND

Waning of vaccine-induced immunity is considered to play a central role in the reemergence of mumps among vaccinated young adults. The aim of the present study was to investigate antibody responses and safety of a third dose of measles-mumps-rubella vaccine (MMR-3) in 150 young adults. Antibody levels were related to a surrogate of protection based on preoutbreak serum antibody levels in 31 persons with and 715 without serological evidence of mumps.

METHODS

Mumps virus-specific immunoglobulin G (IgG) antibody responses and mumps virus-neutralizing antibody responses (based on the focus-reduction neutralizing test) against both the Jeryl Lynn mumps virus vaccine strain (hereafter, the "vaccine strain") and the MuVi/Utrecht.NLD/40.10 outbreak strain (hereafter, the "outbreak strain") were determined, and vaccine safety was evaluated.

RESULTS

Four weeks following MMR-3 receipt, levels of IgG, anti-vaccine strain, and anti-outbreak strain antibodies increased by a factor of 1.65, 1.34, and 1.35, respectively. Although antibody levels decreased 1 year later, they were still above the baseline level by a factor of 1.37, 1.15, and 1.27, respectively. Based on the surrogate protective antibody cutoff, significantly more participants were protected against mumps virus infection up to 1 year after vaccination (ie, they had antibody levels above the presumed threshold for herd immunity).

CONCLUSIONS

MMR-3 receipt increased antibody levels that may protect against mumps virus infection for longer than previously assumed and is expected to be a good and safe intervention for controlling a mumps outbreak.

CLINICAL TRIALS REGISTRATION

2016-001104-36; NTR5911.

Visual tools to assess the plausibility of algorithm-identified infectious disease clusters: an application to mumps data from the Netherlands dating from January 2009 to June 2016

Introduction

With growing amounts of data available, identification of clusters of persons linked to each other by transmission of an infectious disease increasingly relies on automated algorithms. We propose cluster finding to be a two-step process: first, possible transmission clusters are identified using a cluster algorithm, second, the plausibility that the identified clusters represent genuine transmission clusters is evaluated.

Aim

To introduce visual tools to assess automatically identified clusters.

Methods

We developed tools to visualise: (i) clusters found in dimensions of time, geographical location and genetic data; (ii) nested sub-clusters within identified clusters; (iii) intra-cluster pairwise dissimilarities per dimension; (iv) intra-cluster correlation between dimensions. We applied our tools to notified mumps cases in the Netherlands with available disease onset date (January 2009 – June 2016), geographical information (location of residence), and pathogen sequence data (n = 112). We compared identified clusters to clusters reported by the Netherlands Early Warning Committee (NEWC).

Results

We identified five mumps clusters. Three clusters were considered plausible. One was questionable because, in phylogenetic analysis, genetic sequences related to it segregated in two groups. One was implausible with no smaller nested clusters, high intra-cluster dissimilarities on all dimensions, and low intra-cluster correlation between dimensions. The NEWC reports concurred with our findings: the plausible/questionable clusters corresponded to reported outbreaks; the implausible cluster did not.

Conclusion

Our tools for assessing automatically identified clusters allow outbreak investigators to rapidly spot plausible transmission clusters for mumps and other human-to-human transmissible diseases. This fast information processing potentially reduces workload.

Vaccines for measles, mumps, rubella, and varicella in children

BACKGROUND

Measles, mumps, rubella, and varicella (chickenpox) are serious diseases that can lead to serious complications, disability, and death. However, public debate over the safety of the trivalent MMR vaccine and the resultant drop in vaccination coverage in several countries persists, despite its almost universal use and accepted effectiveness. This is an update of a review published in 2005 and updated in 2012.

OBJECTIVES

To assess the effectiveness, safety, and long- and short-term adverse effects associated with the trivalent vaccine, containing measles, rubella, mumps strains (MMR), or concurrent administration of MMR vaccine and varicella vaccine (MMR+V), or tetravalent vaccine containing measles, rubella, mumps, and varicella strains (MMRV), given to children aged up to 15 years.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (the Cochrane Library 2019, Issue 5), which includes the Cochrane Acute Respiratory Infections Group's Specialised Register, MEDLINE (1966 to 2 May 2019), Embase (1974 to 2 May 2019), the WHO International Clinical Trials Registry Platform (2 May 2019), and ClinicalTrials.gov (2 May 2019).

SELECTION CRITERIA

We included randomised controlled trials (RCTs), controlled clinical trials (CCTs), prospective and retrospective cohort studies (PCS/RCS), case-control studies (CCS), interrupted time-series (ITS) studies, case cross-over (CCO) studies, case-only ecological method (COEM) studies, self-controlled case series (SCCS) studies, person-time cohort (PTC) studies, and case-coverage design/screening methods (CCD/SM) studies, assessing any combined MMR or MMRV / MMR+V vaccine given in any dose, preparation or time schedule compared with no intervention or placebo, on healthy children up to 15 years of age.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data and assessed the methodological quality of the included studies. We grouped studies for quantitative analysis according to study design, vaccine type (MMR, MMRV, MMR+V), virus strain, and study settings. Outcomes of interest were cases of measles, mumps, rubella, and varicella, and harms. Certainty of evidence of was rated using GRADE.

MAIN RESULTS

We included 138 studies (23,480,668 participants). Fifty-one studies (10,248,159 children) assessed vaccine effectiveness and 87 studies (13,232,509 children) assessed the association between vaccines and a variety of harms. We included 74 new studies to this 2019 version of the review. Effectiveness Vaccine effectiveness in preventing measles was 95% after one dose (relative risk (RR) 0.05, 95% CI 0.02 to 0.13; 7 cohort studies; 12,039 children; moderate certainty evidence) and 96% after two doses (RR 0.04, 95% CI 0.01 to 0.28; 5 cohort studies; 21,604 children; moderate certainty evidence). The effectiveness in preventing cases among household contacts or preventing transmission to others the children were in contact with after one dose was 81% (RR 0.19, 95% CI 0.04 to 0.89; 3 cohort studies; 151 children; low certainty evidence), after two doses 85% (RR 0.15, 95% CI 0.03 to 0.75; 3 cohort studies; 378 children; low certainty evidence), and after three doses was 96% (RR 0.04, 95% CI 0.01 to 0.23; 2 cohort studies; 151 children; low certainty evidence). The effectiveness (at least one dose) in preventing measles after exposure (post-exposure prophylaxis) was 74% (RR 0.26, 95% CI 0.14 to 0.50; 2 cohort studies; 283 children; low certainty evidence). The effectiveness of Jeryl Lynn containing MMR vaccine in preventing mumps was 72% after one dose (RR 0.24, 95% CI 0.08 to 0.76; 6 cohort studies; 9915 children; moderate certainty evidence), 86% after two doses (RR 0.12, 95% CI 0.04 to 0.35; 5 cohort studies; 7792 children; moderate certainty evidence). Effectiveness in preventing cases among household contacts was 74% (RR 0.26, 95% CI 0.13 to 0.49; 3 cohort studies; 1036 children; moderate certainty evidence). Vaccine effectiveness against rubella is 89% (RR 0.11, 95% CI 0.03 to 0.42; 1 cohort study; 1621 children; moderate certainty evidence). Vaccine effectiveness against varicella (any severity) after two doses in children aged 11 to 22 months is 95% in a 10 years follow-up (rate ratio (rr) 0.05, 95% CI 0.03 to 0.08; 1 RCT; 2279 children; high certainty evidence). Safety There is evidence supporting an association between aseptic meningitis and MMR vaccines containing Urabe and Leningrad-Zagreb mumps strains, but no evidence supporting this association for MMR vaccines containing Jeryl Lynn mumps strains (rr 1.30, 95% CI 0.66 to 2.56; low certainty evidence). The analyses provide evidence supporting an association between MMR/MMR+V/MMRV vaccines (Jeryl Lynn strain) and febrile seizures. Febrile seizures normally occur in 2% to 4% of healthy children at least once before the age of 5. The attributable risk febrile seizures vaccine-induced is estimated to be from 1 per 1700 to 1 per 1150 administered doses. The analyses provide evidence supporting an association between MMR vaccination and idiopathic thrombocytopaenic purpura (ITP). However, the risk of ITP after vaccination is smaller than after natural infection with these viruses. Natural infection of ITP occur in 5 cases per 100,000 (1 case per 20,000) per year. The attributable risk is estimated about 1 case of ITP per 40,000 administered MMR doses. There is no evidence of an association between MMR immunisation and encephalitis or encephalopathy (rate ratio 0.90, 95% CI 0.50 to 1.61; 2 observational studies; 1,071,088 children; low certainty evidence), and autistic spectrum disorders (rate ratio 0.93, 95% CI 0.85 to 1.01; 2 observational studies; 1,194,764 children; moderate certainty). There is insufficient evidence to determine the association between MMR immunisation and inflammatory bowel disease (odds ratio 1.42, 95% CI 0.93 to 2.16; 3 observational studies; 409 cases and 1416 controls; moderate certainty evidence). Additionally, there is no evidence supporting an association between MMR immunisation and cognitive delay, type 1 diabetes, asthma, dermatitis/eczema, hay fever, leukaemia, multiple sclerosis, gait disturbance, and bacterial or viral infections.

AUTHORS' CONCLUSIONS

Existing evidence on the safety and effectiveness of MMR/MMRV vaccines support their use for mass immunisation. Campaigns aimed at global eradication should assess epidemiological and socioeconomic situations of the countries as well as the capacity to achieve high vaccination coverage. More evidence is needed to assess whether the protective effect of MMR/MMRV could wane with time since immunisation.

Mumps: an Update on Outbreaks, Vaccine Efficacy, and Genomic Diversity

Mumps is an acute viral infection characterized by inflammation of the parotid and other salivary glands. Persons with mumps are infectious from 2 days before through 5 days after parotitis onset, and transmission is through respiratory droplets. Despite the success of mumps vaccination programs in the United States and parts of Europe, a recent increase in outbreaks of mumps virus infections among fully vaccinated populations has been reported. Although the effectiveness of the mumps virus component of the measles-mumps-rubella (MMR) vaccine is suboptimal, a range of contributing factors has led to these outbreaks occurring in high-vaccination-coverage settings, including the intensity of exposure, the possibility of vaccine strain mismatch, delayed implementation of control measures due to the timeliness of reporting, a lack of use of appropriate laboratory tests (such as reverse transcription-PCR), and time since last vaccination. The resurgence of mumps virus infections among previously vaccinated individuals over the past decade has prompted discussions about new strategies to mitigate the risk of future outbreaks. The decision to implement a third dose of the MMR vaccine in response to an outbreak should be considered in discussions with local public health agencies. Traditional public health measures, including the isolation of infectious persons, timely contact tracing, and effective communication and awareness education for the public and medical community, should remain key interventions for outbreak control. Maintaining high mumps vaccination coverage remains key to U.S. and global efforts to reduce disease incidence and rates of complications.

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.

Mumps in a highly vaccinated Marshallese community in Arkansas, USA: an outbreak report

BACKGROUND

During 2000-15, Arkansas Department of Health, Little Rock, AR, USA, investigated between one and six cases of mumps each year. From Aug 5, 2016, to Aug 5, 2017, the department received notification of more than 4000 suspected mumps cases in the second largest outbreak in the USA in the past 30 years.

METHODS

Arkansas Department of Health investigated all reported cases of mumps to ascertain exposure, travel, and vaccination histories and identify close contacts. Cases were classified as confirmed if the patient had laboratory confirmation of mumps virus or probable if they had clinical symptoms and either a positive serological test or a known epidemiological link to a confirmed case.

FINDINGS

2954 cases of mumps related to the outbreak were identified during the outbreak period: 1665 (56%) were laboratory confirmed, 1676 (57%) were in children aged 5-17 years, and 1692 (57%) were in Marshallese people. Among the 1676 school-aged cases, 1536 (92%) had previously received at least two doses of a vaccine containing the mumps virus. Although 19 cases of orchitis were reported, severe complications were not identified. Unusual occurrences, such as recurrent parotitis and prolonged viral shedding, were observed mostly in Marshallese individuals. Viral samples were characterised as genotype G.

INTERPRETATION

This large-scale outbreak, primarily affecting a marginalised community with intense household crowding, highlights the need for coordinated, interdisciplinary, and non-traditional outbreak responses. This outbreak raises questions about mumps vaccine effectiveness and potential waning immunity.

FUNDING

Council of State and Territorial Epidemiologists and US Centers for Disease Control and Prevention.

Shift within age-groups of mumps incidence, hospitalizations and severe complications in a highly vaccinated population. Spain, 1998-2014

The mumps vaccine (Jeryl-Lynn-strain) was introduced in Spain in 1981, and a vaccination policy which included a second dose was added in 1995. From 1992-1999, a Rubini-strain based vaccine was administered in many regions but later withdrawn due to lack of effectiveness. Despite high levels of vaccination coverage, epidemics have continued to appear. We characterized the three epidemic waves of mumps between 1998 and 2014, identifying major changes in susceptible populations using Poisson regression. For the period 1998-2003 (P1), the most affected group was from 1 to 4years old (y) [Incidence Rate (IR)=71.7 cases/100,000 population]; in the periods 2004-2009 (P2) and 2010-2014 (P3) IR ratio (IRR) increased among 15-24y (P2=1.46; P3=2.68) and 25-34y (P2=2.17; P3=4.05). Hospitalization rate (HR), complication rate (CR) and neurological complication rate (NR) among hospitalized subjects decreased across the epidemics, except for 25-34y which increased: HR ratio (HRR) (P2=2.18; P3=2.16), CRR (P3=2.48), NRR (P3=2.41). In Spain mumps incidence increased, while an overall decrease of hospitalizations and severe complications occurred across the epidemics. Cohorts born during periods of low vaccination coverage and those vaccinated with Rubini-strain were the most affected populations, leading to a shift in mumps cases from children to adolescents and young adults; this also reveals the waning immunity provided by the mumps vaccine. Despite not preventing all mumps cases, the vaccine appears to prevent serious forms of the disease.

Trend of measles, mumps, and rubella incidence following the measles-rubella catch up vaccination in the Republic of Korea, 2001

Following the introduction of measles-rubella (MR) catch-up vaccination in 2001 and two dose measles-mumps-rubella (MMR2) keep-up program in 2002, the incidence of measles, mumps, and rubella was not evaluated systematically. To describe the recent changes in epidemiology, a population-based incidence study from 2001 to 2015 using national notifiable disease surveillance data was conducted. Between 2001 and 2015, there was decrease in the incidence of measles and rubella, whereas a steady increase in mump incidence was noted. The age distribution of mumps cases has shifted to the older age group, whereas rubella became more frequent in younger age group. The incidence of mumps showed an increase in every birth cohorts, except for the decrease in incidence for catch-up vaccination cohort from 131 cases in 2007-2011 to 64 cases per 100 000 in 2012-2015. Continuing in monitoring of mumps and strengthening of the high two-dose MMR vaccination coverage should be taken place in Korea.

Mumps Outbreak Among a Highly Vaccinated University Community-New York City, January-April 2014

Background

On 14 January 2014, a vaccinated student presented with parotitis. Mumps immunoglobulin M (IgM) testing was negative and reverse-transcription polymerase chain reaction (RT-PCR) testing was not performed, resulting in a missed diagnosis and the start of an outbreak at a New York City (NYC) university.

Methods

Mumps case investigations included patient interviews, medical records review, and laboratory testing including mumps serology and RT-PCR. Case patients were considered linked to the outbreak if they attended or had epidemiologic linkage to the university. Epidemiologic, clinical, and laboratory data for outbreak cases residing in NYC were analyzed.

Results

Fifty-six NYC residents with mumps were identified with onset between 12 January and 30 April 2014. Fifty-three cases (95%) were university students, 1 (2%) was a staff member, and 2 (4%) had epidemiologic links to the university. The median age was 20 years (range 18-37 years). All cases had parotitis. Three cases were hospitalized, including 1 of 2 cases with orchitis. Fifty-four (96%) cases had received ≥1 mumps-containing vaccine, 1 (2%) was unvaccinated due to religious exemption, and 1 (2%) had unknown vaccination status. Two of the 44 (5%) cases tested by serology were mumps IgM positive, and 27 of the 40 (68%) tested by RT-PCR were positive.

Conclusions

Mumps outbreaks can occur in highly vaccinated populations. Mumps should be considered in patients with parotitis regardless of vaccination status. RT-PCR is the preferred testing method; providers should not rely on IgM testing alone. High vaccination coverage and control measures likely limited the extent of the outbreak.

Mumps transmission in social networks: a cohort study

BACKGROUND

Mumps emerged among highly vaccinated populations in the Netherlands. This offered a unique opportunity to study mumps virus transmission. In particular the extent to which asymptomatic infections in vaccinated people contribute to ongoing mumps virus transmission is uncertain. Insight into this could help project the future burden of mumps in vaccinated populations. We therefore studied the relative infectiousness of symptomatic and asymptomatic cases.

METHODS

In a cohort study we followed contacts of notified mumps cases (ring 1) and contacts' contacts (ring 2) for 40 days to ascertain symptoms of mumps and social contacts by weekly diaries and questionnaires, and mumps virus infections by taking finger stick dried blood spot specimens (DBS) that were tested for mumps-specific IgG antibodies. Mumps IgG concentrations >1500 RU/ml in a single sample, a four-fold increase in IgG antibody concentration in paired samples, or a positive oral fluid PCR were defined as recent infection.

RESULTS

We recruited 99 contacts (40 in ring 1 and 59 in ring 2) of 10 mumps index cases. The median age of participants was 23 years (range 18-57 years), 31 (31%) were male. At study entry, DBS of 4 out of 78 (5%) participants with samples showed serological evidence of recent mumps virus infection. Three of these reported mumps symptoms. Among the 59 participants who provided DBS at the beginning and end of the follow-up period, none had serological evidence of infection during this period. Of 72 participants who provided at least one oral fluid sample, one participant (1%) who also reported mumps symptoms, was found PCR positive. Of all 99 participants, the attack rate of self-reported mumps was 4% (95% CI 1.1-10.0%). Of the 5 laboratory confirmed mumps cases, 1 reported no mumps symptoms (percentage asymptomatic 20% (95% CI 0-71%)). Compared to non-students, students had larger households and more household members who were born after 1980 (p < 0.01 and <0.01, respectively).

CONCLUSIONS

We demonstrated that this prospective cohort study design allows for inference of the proportion of asymptomatic mumps infections. Because we only detected one asymptomatic mumps virus infection, we could not assess the relative infectiousness of asymptomatic mumps. Household characteristics of students differed from non-students. This may partly explain recent mumps epidemiology in the Netherlands.

Three cases of mumps virus and enterovirus coinfection in children with enteroviral meningitis

Several viruses are responsible for aseptic meningitis; however, in the region of Southwest Iran, the role played by each virus is still not very well known. The aim of this study is to determine the relative frequencies of mumps virus, herpes viruses, and enteroviruses, as well as coinfections among them, in patients with aseptic meningitis.In this cross-sectional study, samples of cerebrospinal fluid were collected between December 2012 and December 2013 from patients under 14 years, who were hospitalized in Abuzar Children's Hospital in Ahvaz, Southwest Iran (the only children's hospital in Khuzestan province and Southwest Iran).All 66 cerebrospinal fluid samples and corresponding clinical data were collected from patients with aseptic meningitis by specialists, and with the patients' consent. The DNA and RNA were extracted from these samples and subjected to polymerase chain reaction as well as reverse transcription polymerase chain reaction (RT-PCR) for detection of mumps virus, herpes viruses, and enteroviruses. Nine of the samples (3 mumps-positive and 6 enterovirus-positive) were sequenced. The mumps virus sequences were investigated for possible mutations in the SH and partial HN regions.Up to 39 patients (59.09%) were found to be positive for enteroviruses, 3 (4.5%) for mumps virus, and 1 (1.5%) for herpes viruses (specifically, the varicella-zoster virus). Two patients (3.03%) had a mumps virus and enterovirus coinfection. Among the 3 detected mumps virus samples, 1 belonged to genotype B, while the others belonged to genotype N. Six sequenced enteroviruses indicated the highest similarity with Echovirus 30. An amino acid substitution at position 51 (N→T) was detected in the HN region of genotype N mumps virus samples, in comparison to the reference strain.

How will the MMR universal mass vaccination change the epidemiologic pattern of mumps? A 2012 Italian serosurvey

To investigate the changes in the epidemiologic pattern of mumps, we carried out a serosurvey among young adults from Apulia, Italy. A convenience sample of 1,764 blood donors were enrolled in 2012: 93.4% (95% confidence interval, 92.1-94.5) showed a positive antimumps immunoglobulin G titre, geometric mean titer was 2.05. Results were consistent with previously published data on the immunogenicity of mumps vaccine but showed a lack of immunity (10% of people aged 18-26 years susceptible for mumps). Future research must be focused on the long-time immunogenicity of the mumps vaccine.

Mumps virus pathogenesis: Insights and knowledge gaps

The recent mumps outbreaks among MMR vaccinated persons have raised questions about the biological mechanisms related to mumps symptoms and complications in the background of waning immunity. Contrary to other paramyxoviruses, the understanding of mumps virus pathogenesis is limited, and further in-depth clinical studies are required to provide answers to important research questions.

Seroepidemiology of mumps in the general population of Jiangsu province, China after introduction of a one-dose measles-mumps-rubella vaccine

The mumps surveillance data from 2004 to 2011 showed that the incidence of mumps remained high after the one-dose measles-mumps-rubella (MMR) vaccine was introduced in China in 2008. A cross-sectional survey of mumps IgG in the general population of Jiangsu province was conducted in 2012 to gain comprehensive information on the immunity profile of the general population. The mean incidence was 15.2 per 100 000 individuals in Jiangsu province from 2004–2013. Two mumps incidence peaks were observed each year after introduction of the one-dose MMR vaccine. The seroprevalence did not significantly differ by region or sex, while the GMC significantly differed by region and sex. The overall GMC in Jiangsu province was 99.1 IU/ml (95% CI: 90.1–108.2), while the seroprevalence was only 59.1% (95% CI: 56.5–61.6). The seroprevalences for the 2 age groups that received the one-dose MMR vaccine, with reported coverage exceeding 95%, were 42.6% and 70.0%, respectively. The data on the incidence, MMR coverage, and seroprevalence in children younger than 6 years of age indicate that a two-dose MMR strategy should be considered. Mumps surveillance should be strengthened in children aged 6–11 and in those aged 12–17 because of their high contact rates and relatively low seroprevalences.

The relationship between meteorological factors and mumps incidence in Guangzhou, China, 2005-2012:

BACKGROUND

Over the past decade, there have been resurgences and large-scale outbreaks of mumps worldwide. Little evidence is available on the relationship between meteorological factors and the incidence of mumps. We aimed to explore the effects of meteorological factors on mumps incidence.

METHODS

A Poisson regression model combined with a distributed lag non-linear model (DLNM) was used to evaluate the association between meteorological factors and the mumps incidence in Guangzhou, China, 2005-2012.

RESULTS

Nonlinear relationships between meteorological factors, except sunshine hours, and mumps incidence were observed. The relative risks (RRs) of mean temperature, relative humidity and atmospheric pressure were 1.81 (95% confidence interval (CI), 1.41 to 2.32), 1.28 (95% CI, 1.02 to 1.59), and 0.80 (95% CI, 0.67 to 0.95) comparing the 99th percentile to the median of their own, respectively. For wind velocity, the RR was 0.70 (95%CI, 0.54 to 0.91) comparing the 1st percentile to the median. The hot effect and cold effect were larger in females than in males, and the hot effect increased with age.

CONCLUSIONS

Mean temperature, relative humidity, wind velocity and atmospheric pressure might be important predictors of the mumps incidence. Tropical cyclone caused a higher increase in mumps cases. Our findings highlight the need to strengthen the awareness of using protective measures during typhoon days and allocating more attention to the susceptible populations during the summer. The two-dose regimen of mumps vaccine should be included in the National Immunization Program schedule, and the catch-up vaccination campaigns should be promoted among adults.

Determinants of students' willingness to accept a measles-mumps-rubella booster vaccination during a mumps outbreak: a cross-sectional study

Background

Despite high vaccination coverage, a mumps outbreak that affected mainly vaccinated university students and their contacts took place in the Netherlands in the period 2009–2012. We presented university students with a hypothetical case in which we offered them a measles, mumps, and rubella (MMR) booster vaccination to control the mumps outbreak. The aim of this study was to get insight into the determinants of university students' willingness to accept this vaccination.

Methods

A questionnaire containing 38 items was developed for the purpose of assessing students' willingness and the psychosocial and social demographic determinants influencing their willingness to accept an MMR booster vaccination. In addition, we explored how organisational characteristics influenced the willingness to be vaccinated. Data were collected at six Dutch universities; a total of 790 students from various faculties were invited to participate. This was a convenience sampling procedure.

Results

687 university students participated (response rate 87.0 %) and 60.4 % of the participants said they would be willing accept the hypothetical MMR booster vaccination. The perceived seriousness of mumps (OR 6.1) was the most important predictor of willingness to accept vaccination. Students who expected the MMR vaccination to be effective and to prevent individual illness and who believed their own vaccination would help stop the epidemic were more likely to be willing than others. The students were more willing to accept vaccination when they perceived that the social norms of significant others and the government favoured vaccination. Organisational characteristics, such as offering vaccination cost free and offering it at the university site, increased students’ willingness.

Conclusion

During a mumps outbreak, university students were generally willing to accept a hypothetical MMR booster vaccination. Risk perception, outcome expectations, perceived social norms, and organisational characteristics should be taken into account in the planning of any vaccination campaign for university students during an outbreak of an infectious disease.

Dynamics of the serologic response in vaccinated and unvaccinated mumps cases during an epidemic

In the last decade, several mumps outbreaks were reported in various countries despite high vaccination coverage. In most cases, young adults were affected who have acquired immunity against mumps solely by vaccination and not by previous wild-type mumps virus infection. To investigate mumps-specific antibody levels, functionality and dynamics during a mumps epidemic, blood samples were obtained longitudinally from 23 clinical mumps cases, with or without a prior history of vaccination, and from 20 healthy persons with no serological evidence of recent mumps virus infection. Blood samples from mumps cases were taken 1-2 months and 7-10 months after onset of disease. Both vaccinated and unvaccinated mumps cases had significantly higher geomean concentrations of mumps-specific IgG (resp. 13,617 RU/ml (95% CI of 9,574-19,367 RU/ml) vs. 1,552 (445-5412) RU/ml at 1-2 months; and 6,514 (5,247-8,088) RU/ml vs. 1,143 (480-2,725) RU/ml at 7-10 months) than healthy controls (169 (135-210) RU/ml) (p = 0.001). Patterns in virus-neutralizing (VN) antibody responses against the mumps vaccine virus were similar, vaccinated and unvaccinated mumps cases had significantly higher ND50 values at both time points of sampling (resp 4,695 (3,779-5,832) RU/ml vs. 1,533 (832-2,825) RU/ml at 1-2 months; 2,478 (1,968-3,122) RU/ml vs. 1,221 (1,029-1,449) RU/ml at 7-10 months) compared with (previously vaccinated) healthy controls (122 (196-76)) RU/ml) (p = 0.001) The unvaccinated mumps cases had significantly lower mumps-specific IgG and VN antibody concentrations at both sampling points compared with previously vaccinated cases, but their antibody concentrations did not differ significantly at the 2 time points. In contrast, the mumps-specific IgG and VN antibody concentrations of the previously vaccinated mumps cases were significantly higher within the first 2 months after onset of mumps and declined thereafter, characteristic for a secondary response. A moderate correlation was found between the level of mumps-specific IgG serum antibodies and VN antibodies for the mumps cases (r = 0.64; p<0.001).

Epidemic of mumps among vaccinated persons, The Netherlands, 2009-2012

To analyze the epidemiology of a nationwide mumps epidemic in the Netherlands, we reviewed 1,557 notified mumps cases in persons who had disease onset during September 1, 2009–August 31, 2012. Seasonality peaked in spring and autumn. Most case-patients were males (59%), 18–25 years of age (67.9%), and vaccinated twice with measles-mumps-rubella vaccine (67.7%). Nearly half (46.6%) of cases occurred in university students or in persons with student contacts. Receipt of 2 doses of vaccine reduced the risk for orchitis, the most frequently reported complication (vaccine effectiveness [VE] 74%, 95% CI 57%–85%); complications overall (VE 76%, 95% CI 61%–86%); and hospitalization (VE 82%, 95% CI 53%–93%). Over time, the age distribution of case-patients changed, and proportionally more cases were reported from nonuniversity cities (p<0.001). Changes in age and geographic distribution over time may reflect increased immunity among students resulting from intense exposure to circulating mumps virus.

Mumps serum antibody levels before and after an outbreak to assess infection and immunity in vaccinated students

Background

 Since 2009, various mumps outbreaks have occurred in the Netherlands, affecting mostly young adults vaccinated against mumps. In this retrospective study, we estimated attack rates for symptomatic and asymptomatic mumps virus infection based on mumps-specific immunoglobulin (Ig)G concentrations in paired blood samples obtained before and after the mumps outbreaks, collected in 2 university cities. We aimed to identify a serological correlate of immune protection and risk factors for mumps virus infection.

Methods

 Mumps-specific IgG levels were measured by Luminex technology in paired pre- and post-outbreak samples from students from Leiden (n = 135) and Utrecht (n = 619). Persons with a 4-fold increase in mumps IgG concentrations or mumps IgG concentrations >1500 RU/mL were assumed to have had a mumps virus infection.

Results

 Attack rates for symptomatic and asymptomatic mumps virus infection were 2.0% and 3.8%, respectively. Pre-outbreak mumps-specific IgG concentrations were lower among cases than among noncases (P = .005) despite vaccination history, but no serological cutoff for immune protection could be established. Mumps among housemates was significantly associated with serological evidence for mumps virus infection (odds ratio, 7.25 [95% confidence interval, 3.20–16.40]; P < .001).

Conclusions

 Symptomatic and asymptomatic mumps virus infections in vaccinated persons can be identified by retrospective assessment of mumps-specific IgG antibodies in blood samples.

Mumps virus infection in vaccinated patients can be detected by an increase in specific IgG antibodies to high titres: a retrospective study

Mumps outbreaks in highly vaccinated populations with genotype G have been reported repeatedly. Detection of these outbreaks can be difficult in a setting with relatively high vaccination coverage when acute cases of mumps are routinely diagnosed by IgM serology since this marker is not reliable for diagnosis of mumps re-infection. To learn whether diagnostic tests performed in a large private laboratory may be useful to detect mumps outbreaks retrospectively, we reviewed the results of almost 7000 mumps tests. Two groups were compared: group 1 comprised of 3438 samples from patients submitted by physicians and clinicians (it was assumed that these patients visited their doctor due to acute disease). Group 2 comprised of 3398 samples submitted from company medical officers and occupational physicians. Since these patients usually attend for routine check-ups and certification of immunity to vaccine-preventable diseases, these samples comprised a control group. From July 2010 to May 2011, a mumps virus outbreak with more than 300 cases occurred in Bavaria, Southeast Germany. Our study includes samples received for serological mumps tests from January 2009 until December 2011 (36 months). The two groups were analysed with regard to the number of IgM-positive cases per month and the level of IgG titre. We found a marked increase for both parameters in group 1 during the time of the outbreak, while the samples submitted by the occupational medical physicians did not display significant alterations. These parameters reflect the outbreak with high accuracy, indicating that a retrospective analysis of IgG titres may be a useful tool for detection of mumps outbreaks when, as was the case in Germany, (i) a nationwide notification system has not been implemented and (ii) a highly vaccinated population is affected.

Epidemic of complicated mumps in previously vaccinated young adults in the South-West of France

OBJECTIVE

We report the features and diagnosis of complicated mumps in previously vaccinated young adults.

PATIENTS AND METHODS

We retrospectively studied 7 cases of complicated mumps managed during 1 year at the Bordeaux University Hospital. The diagnosis was suggested by the clinical presentation and confirmed using specific RT-PCR.

RESULTS

Five cases of meningitis, 1 of orchitis, and 1 of unilateral hearing impairment were identified. Each of the 7 patients had been previously vaccinated with MMR, 4 had received 2 doses of this vaccine. Blood tests revealed high rates of IgG antibodies, usually considered as sufficient for immunological protection, and every patient had at least 1 positive RT-PCR test for mumps.

CONCLUSION

Outbreaks of complicated mumps may still occur despite a broad coverage of MMR vaccination. The clinical presentation suggested mumps but the final diagnosis could only be confirmed by genomic detection of the virus. Unusual viral strains with increased neurovirulence, insufficient population coverage associated with immunity decrease over time may explain outbreaks of complicated mumps. A full vaccine scheme of contact people or a third injection of vaccine for previously vaccinated people who are at risk of developing mumps are required to prevent further spreading of the disease during the outbreak.

Outbreaks of mumps: an observational study over two decades in a single hospital in Korea

Purpose

The introduction of the mumps vaccine has dramatically reduced the number of mumps cases, but outbreaks have recently occurred among highly vaccinated populations in developed countries. Epidemiological and clinical characteristics of patients with mumps admitted between 1989 and 2012 in a single hospital in Korea are described in the present study.

Methods

We retrospectively evaluated inpatients with mumps between 1989 and 2012 and outpatients and inpatients with mumps in 2011-2012.

Results

A total of 152 patients with mumps were admitted between 1989 and 2012, and 163 patients were recorded in 2011-2012. The highest number of admitted cases occurred in 1998 and 2012 (35 and 34 cases, respectively). Among the patients admitted in 2011-2012, the highest frequency was observed among people aged 15-19 years, and low frequency was observed in those aged <4 years and >20 years, compatible to the city data and national data. In patients admitted to our department in 1998 (35 cases) and in 2010-2012 (27 cases), there were significant differences in the mean age and the rate of secondary measles-mumps-rubella (MMR) vaccination, but had similar clinical features, including complications, except aseptic meningitis. Antimumps immunoglobulin (Ig) G was positive in 83% and 100%, and IgM was positive in 67% and 41%, respectively, in the two periods.

Conclusion

In Korea, recent mumps outbreaks have occurred mainly among secondary school students who received two doses of the MMR vaccine. The vaccinees might have a modified immune reaction to viral insults, manifesting modified epidemiological and clinical features.

Two major mumps genotype G variants dominated recent mumps outbreaks in the Netherlands (2009–2012)

During three seasons of mumps outbreaks in the Netherlands (September 2009–August 2012), 822 mumps cases were laboratory-confirmed at the National Institute for Public Health and the Environment (RIVM). Most patients were vaccinated young adults. Given the protracted endemic circulation, we studied the genetic diversity and changes of mumps virus over a period of 3 years. Phylogenetic analysis of the small hydrophobic (SH) gene (316 bp) was performed on a representative set of 808 specimens that tested positive for mumps via PCR. Additionally, the haemagglutinin/neuraminidase (HN) gene (1749 bp) and fusion (F) gene (1617 bp) were sequenced for a subset of samples (n = 17). Correlations between different sequence types and epidemiological and clinical data were investigated. The outbreaks in the Netherlands were dominated by two SH gene sequence types within genotype G, termed MuVs/Delft.NLD/03.10 (variant 1) and MuVs/Scheemda.NLD/12.10 (variant 2). Sequence analysis of the HN and F genes indicated that the outbreaks were initiated by separately introduced genetic lineages. The predominance of variant 2 by the end of the first outbreak season could not be explained by any of the epidemiological factors investigated. Orchitis was more frequently reported in males infected with variant 2, irrespective of age and vaccination status. These findings illustrate genetic heterogeneity of an emerging mumps genotype, and raise questions about the mechanisms driving mumps epidemiology and immunity in relation to vaccination.

Smoking and older age associated with mumps in an outbreak in a group of highly-vaccinated individuals attending a youth club party, the Netherlands, 2012

We describe a mumps outbreak in a highly-vaccinated population attending a party at a youth club. In a retrospective cohort study with 60 of approximately 100 participants responding, vaccination status was verified for 58/59 respondents, of whom 54 were vaccinated twice and four once. The attack rate was 22% (13 cases, all vaccinated), with smoking at the party (risk ratio (RR) 3.1; 95% confidence interval (CI): 1.6–6.0, p=0.001) and age ≥21 years (RR 4.7; 95% CI: 2.1–10.2, p<0.0001) as risk factors for disease in the binominal regression analysis. Mild upper respiratory illness was also highly prevalent in those who did not meet the mumps case definition (n=46) after the party, suggesting that mumps virus infection may cause mild disease in vaccinated individuals. Our investigation adds toevidence that crowded social events and smoking may facilitate spread of mumps virus among vaccinated populations, with waning immunity playing a role. The suggestion that mumps virus infection in vaccinated individuals may manifest as mild upper respiratory illness could have implications for transmission and warrants further investigation.

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.

Lower transplacental antibody transport for measles, mumps, rubella and varicella zoster in very preterm infants

BACKGROUND

Maternal antibodies, transported over the placenta during pregnancy, contribute to the protection of infants from infectious diseases during the first months of life. In term infants, this protection does not last until the first recommended measles-mumps-rubella vaccination at 14 months in the Netherlands, while these viruses still circulate. The aim of the study was to investigate the antibody concentration against measles, mumps, rubella and varicella (MMRV) in mothers and preterm infants or healthy term infants at birth.

METHODS

Antibody concentrations specific for MMRV were measured in cord blood samples from preterm (gestational age <32 weeks and/or birth weight <1500 g) and term infants, and matched maternal serum samples, using a fluorescent bead-based multiplex immune-assay.

RESULTS

Due to lower placental transfer ratios of antibodies against MMRV in 96 preterm infants (range 0.75-0.87) compared to 42 term infants (range 1.39-1.65), the preterm infants showed 1.7-2.5 times lower geometric mean concentrations at birth compared to term infants. Maternal antibody concentration is the most important determinant of infant antibody concentration against MMRV.

CONCLUSIONS

Preterm infants benefit to a lesser extent from maternal antibodies against measles, mumps, rubella and varicella than term infants, posing them even earlier at risk for infectious diseases caused by these still circulating viruses.

Risk factors for transmission of mumps in a highly vaccinated population in Orange County, NY, 2009-2010

BACKGROUND

In 2009-2010, we investigated a mumps outbreak among a highly vaccinated Orthodox Jewish population in a village in Orange County, NY, to identify risk factors associated with mumps transmission among persons with 2 doses of mumps-containing vaccine.

METHODS

Demographic and epidemiologic characteristics were collected on students in grades 6-12 in 3 schools. A mumps case was defined as a student, who self-reported parotitis, orchitis, jaw swelling and/or a mumps-related complication or whose mumps illness was reported to the Orange County Health Department during September 1, 2009, to January 18, 2010. Log-binomial regression analyses were conducted separately for boys and girls as they attended different schools and had different hours of study.

RESULTS

Of the 2503 students with 2 documented doses of mumps-containing vaccine, 320 (13%) developed mumps. Risk of mumps increased with increasing number of mumps cases in the class [≥8 vs. ≤3 cases: boys aRR = 3.1; 95% confidence interval (CI): 2.0-5.0; girls aRR = 2.6; 95% CI: 1.6-4.1] and household (>1 vs. 0 cases: boys aRR = 4.3 95% CI: 3.7-5.6; girls aRR = 10.1 95% CI: 7.1-14.3). Age at first dose, time since last dose, time between first and second dose, school, class size, number of hours at school per week and household size were not significantly associated with having mumps.

CONCLUSIONS

Two doses of mumps-containing vaccine may not be as effective in outbreak settings with multiple, prolonged and intense exposure. Additional studies are required to understand why such mumps outbreaks occur and how they can be prevented in the future.

Immunogenicity of novel mumps vaccine candidates generated by genetic modification

Mumps is a highly contagious human disease, characterized by lateral or bilateral nonsuppurative swelling of the parotid glands and neurological complications that can result in aseptic meningitis or encephalitis. A mumps vaccination program implemented since the 1960s reduced mumps incidence by more than 99% and kept the mumps case numbers as low as hundreds of cases per year in the United States before 2006. However, a large mumps outbreak occurred in vaccinated populations in 2006 and again in 2009 in the United States, raising concerns about the efficacy of the vaccination program. Previously, we have shown that clinical isolate-based recombinant mumps viruses lacking expression of either the V protein (rMuVΔV) or the SH protein (rMuVΔSH) are attenuated in a neurovirulence test using newborn rat brains (P. Xu et al., Virology 417:126-136, 2011, http://dx.doi.org/10.1016/j.virol.2011.05.003; P. Xu et al., J. Virol. 86:1768-1776, 2012, http://dx.doi.org/10.1128/JVI.06019-11) and may be good candidates for vaccine development. In this study, we examined immunity induced by rMuVΔSH and rMuVΔV in mice. Furthermore, we generated recombinant mumps viruses lacking expression of both the V protein and the SH protein (rMuVΔSHΔV). Analysis of rMuVΔSHΔV indicated that it was stable in tissue culture cell lines. Importantly, rMuVΔSHΔV was immunogenic in mice, indicating that it is a promising candidate for mumps vaccine development.

Estimation of vaccine efficacy and critical vaccination coverage in partially observed outbreaks

Classical approaches to estimate vaccine efficacy are based on the assumption that a person's risk of infection does not depend on the infection status of others. This assumption is untenable for infectious disease data where such dependencies abound. We present a novel approach to estimating vaccine efficacy in a Bayesian framework using disease transmission models. The methodology is applied to outbreaks of mumps in primary schools in the Netherlands. The total study population consisted of 2,493 children in ten primary schools, of which 510 (20%) were known to have been infected, and 832 (33%) had unknown infection status. The apparent vaccination coverage ranged from 12% to 93%, and the apparent infection attack rate varied from 1% to 76%. Our analyses show that vaccination reduces the probability of infection per contact substantially but not perfectly ([Formula: see text] = 0.933; 95CrI: 0.908-0.954). Mumps virus appears to be moderately transmissible in the school setting, with each case yielding an estimated 2.5 secondary cases in an unvaccinated population ([Formula: see text] = 2.49; 95%CrI: 2.36-2.63), resulting in moderate estimates of the critical vaccination coverage (64.2%; 95%CrI: 61.7-66.7%). The indirect benefits of vaccination are highest in populations with vaccination coverage just below the critical vaccination coverage. In these populations, it is estimated that almost two infections can be prevented per vaccination. We discuss the implications for the optimal control of mumps in heterogeneously vaccinated populations.

Seroprevalence of mumps in The Netherlands: dynamics over a decade with high vaccination coverage and recent outbreaks

Here we present mumps virus specific antibody levels in a large cross-sectional population-based serosurveillance study performed in the Netherlands in 2006/2007 (n = 7900). Results were compared with a similar study (1995/1996) and discussed in the light of recent outbreaks. Mumps antibodies were tested using a fluorescent bead-based multiplex immunoassay. Overall seroprevalence was 90.9% with higher levels in the naturally infected cohorts compared with vaccinated cohorts. Mumps virus vaccinations at 14 months and 9 years resulted in an increased seroprevalence and antibody concentration. The second vaccination seemed to be important in acquiring stable mumps antibody levels in the long term. In conclusion, the Dutch population is well protected against mumps virus infection. However, we identified specific age- and population groups at increased risk of mumps infection. Indeed, in 2007/2008 an outbreak has occurred in the low vaccination coverage groups emphasizing the predictive value of serosurveillance studies.

Mumps outbreak in Orthodox Jewish communities in the United States

BACKGROUND

By 2005, vaccination had reduced the annual incidence of mumps in the United States by more than 99%, with few outbreaks reported. However, in 2006, a large outbreak occurred among highly vaccinated populations in the United States, and similar outbreaks have been reported worldwide. The outbreak described in this report occurred among U.S. Orthodox Jewish communities during 2009 and 2010.

METHODS

Cases of salivary-gland swelling and other symptoms clinically compatible with mumps were investigated, and demographic, clinical, laboratory, and vaccination data were evaluated.

RESULTS

From June 28, 2009, through June 27, 2010, a total of 3502 outbreak-related cases of mumps were reported in New York City, two upstate New York counties, and one New Jersey county. Of the 1648 cases for which clinical specimens were available, 50% were laboratory-confirmed. Orthodox Jewish persons accounted for 97% of case patients. Adolescents 13 to 17 years of age (27% of all patients) and males (78% of patients in that age group) were disproportionately affected. Among case patients 13 to 17 years of age with documented vaccination status, 89% had previously received two doses of a mumps-containing vaccine, and 8% had received one dose. Transmission was focused within Jewish schools for boys, where students spend many hours daily in intense, face-to-face interaction. Orchitis was the most common complication (120 cases, 7% of male patients ≥12 years of age), with rates significantly higher among unvaccinated persons than among persons who had received two doses of vaccine.

CONCLUSIONS

The epidemiologic features of this outbreak suggest that intense exposures, particularly among boys in schools, facilitated transmission and overcame vaccine-induced protection in these patients. High rates of two-dose coverage reduced the severity of the disease and the transmission to persons in settings of less intense exposure.