Mumps outbreak in a highly vaccinated student population,The Netherlands, 2004

In September 2004 a mumps outbreak occurred at an international hotel school in The Netherlands. We investigated this outbreak to identify risk factors for mumps. There were 105 mumps cases (overall mumps attack rate (AR) 12% (95% CI: 10–15%)). The AR for Dutch vaccinated and unvaccinated participants was 12% (95% CI: 10–15%) and 15% (95% CI: 3–42%), respectively. Independent risk factor was mumps contact. Explanations for the relatively high AR among vaccinated participants include primary vaccine failure, waning immunity and incomplete vaccine-induced immunity in the context of high mumps virus exposure in a school party and a crowded boarding school.     

Mumps outbreak and MMR IgG surveillance as a predictor for immunity in military trainees

In 2017, a mumps outbreak occurred in a barrack holding 249 service members. Suspected cases were evaluated with a combination of mumps IgG, IgM, viral culture, PCR and sequencing. Seven cases were diagnosed in febrile patients presenting with parotitis or orchitis. Mumps infection was confirmed by IgM or positive PCR with 5/7 cases having notable IgG levels before infection. Sequencing confirmed mumps genotype G strain. Serum from all 249 service members collected prior to the outbreak was withdrawn from the Department of Defense (DoD) Serum Repository and the IgG values of measles, mumps and rubella determined with 20.2%, 12.3% and 9.7% service members being seronegative, respectively. No specific IgG seronegativity combination predicted IgG marker levels to another virus within the same vaccine. This paper provides additional evidence that mumps serology is not a reliable surrogate for mumps immunity and that we need better laboratory correlates to confirm immunity.     

2016–2017 Arkansas mumps outbreak in a close-knit community: Assessment of the economic impact and response strategies

On August 8, 2016, a confirmed case of mumps was reported to the Arkansas Department of Health (ADH) in an adult resident of Springdale, Arkansas. By July 2017, nearly 3,000 cases of mumps were reported to ADH from 37 of the 75 counties in Arkansas. Over 50% of cases were in the Arkansas Marshallese community, a close-knit community characterized by large, and extended families sharing the same living space and communal activities. In a statewide effort, ADH collaborated with CDC, the Republic of the Marshall Island’s (RMI) Ministry of Health, and the Arkansas Department of Education (ADE) to rapidly respond to and contain the outbreak. We assessed the economic burden to ADH of the outbreak response in terms of containment and vaccination costs, as well as response costs incurred by CDC, RMI, and ADE. The 2016–2017 Arkansas mumps outbreak was the second largest US mumps outbreak in over 30 years and was unique in size, spread, and population affected. Total public health response costs as a result of the outbreak were over $2.1 million, approximately $725 per case. The costs incurred to control this outbreak reflect the response strategies tailored to the affected populations, including consideration of social, cultural, and political factors in controlling transmission and requirements of distinctive strategies for public health outreach. Aside from the burden these outbreaks have on the affected population, we demonstrate the potential for high economic burden of these outbreaks to public health.     

Genomic characterization of mumps viruses from a large-scale mumps outbreak in Arkansas, 2016

In 2016, a year-long large-scale mumps outbreak occurred in Arkansas among a highly-vaccinated population. A total of 2954 mumps cases were identified during this outbreak. The majority of cases (1676 (57%)) were school-aged children (5–17 years), 1536 (92%) of these children had completed the mumps vaccination schedule. To weigh the possibility that the mumps virus evaded vaccine-induced immunity in the affected Arkansas population, we established a pipeline for genomic characterization of the outbreak strains. Our pipeline produces whole-genome sequences along with phylogenetic analysis of the outbreak mumps virus strains. We collected buccal swab samples of patients who tested positive for the mumps virus during the 2016 Arkansas outbreak, and used the portable Oxford Nanopore Technology to sequence the extracted strains. Our pipeline identified the genotype of the Arkansas mumps strains as genotype G and presented a genome-based phylogenetic tree with superior resolution to a standard small hydrophobic (SH) gene-based tree. We phylogenetically compared the Arkansas whole-genome sequences to all publicly available mumps strains. While these analyses show that the Arkansas mumps strains are evolutionarily distinct from the vaccine strains, we observed no correlation between vaccination history and phylogenetic grouping. Furthermore, we predicted potential B-cell epitopes encoded by the Arkansas mumps strains using a random forest prediction model trained on antibody-antigen protein structures. Over half of the predicted epitopes of the Jeryl-Lynn vaccine strains in the Hemagglutinin-Neuraminidase (HN) surface glycoprotein (a major target of neutralizing antibodies) region are missing in the Arkansas mumps strains. In-silico analyses of potential epitopes may indicate that the Arkansas mumps strains display antigens with reduced immunogenicity, which may contribute to reduced vaccine effectiveness. However, our in-silico findings should be assessed by robust experiments such as cross neutralization assays. Metadata analysis showed that vaccination history had no effect on the evolution of the Arkansas mumps strains during this outbreak. We conclude that the driving force behind the spread of the mumps virus in the 2016 Arkansas outbreak remains undetermined.     

流行性腮腺炎流行病学调查分析与控制对策

目的分析新兴县流行性腮腺炎的流行病学特点，以提供防治参考。方法运用描述性流行病学的统计方法对新兴县2008年报告的腮腺炎病例进行分析。结果新兴县2008年1月至12月共报告流行性腮腺炎23例，年报告发病率为4.98／10万，病例主要集中在流动人口较多的新城镇、太平镇等地区，6月为高发月份，占总发病数26.08％，发病人群主要是10-15岁小学生，占60.86％，腮腺炎相关疫苗免疫史空白和免疫史不详占73.73％。结论加强儿童腮腺炎疫苗的接种工作，重点是流动儿童，发生疫情及时采取综合措施，是控制流行性腮腺炎疫情的重要手段。     

An outbreak of mumps among young adults in Vancouver, British Columbia, associated with 'rave' parties.

In early 1997 an unexpectedly high number of cases of mumps was reported in Vancouver, British Columbia. METHODS: A case control study was conducted to address four objectives: 1) Describe the outbreak and the population at risk, 2) examine the impact of mumps on this population, 3) identify personal risk factors for infection, and 4) test the hypothesis that social gatherings, 'rave' parties in particular, were a risk factor in this outbreak. RESULTS: Mumps infection was associated with: attending a rave party [OR = 17; 95% CI: 2.7-710], residing in Vancouver [OR = 3.7; 95% CI: 1.4-10], and contact with a person with mumps [OR = 13; 95% CI: 2-552], during the 'exposure' period. Vaccine effectiveness, ascertained by self-reported immunization status, was 80% [95% CI: 29%-96%]. CONCLUSIONS: Attendance at rave parties was associated with mumps infection during this outbreak. Many persons aged 17-40 may remain susceptible to mumps; in BC these persons are eligible for one dose of MMR and should be encouraged to be vaccinated.     

Hospital-associated measles outbreak - Pennsylvania, March-April 2009

Although endemic measles transmission has been interrupted in the United States, importations of this highly infectious virus continue. On March 28, 2009, a physician notified the Pennsylvania Department of Health (PADOH) of a measles case involving an unvaccinated child. Within 5 days, four additional cases were reported to PADOH and the Allegheny County Health Department. All five infected persons had been in the same hospital emergency department (ED) on March 10; one of them was a physician who worked in the ED. To find the source patient, PADOH reviewed electronic records of patients evaluated in the ED on March 10 for fever and rash. This identified a child who arrived recently from India, was treated for viral exanthema, and discharged. On April 3, PADOH obtained serum from this child and confirmed a diagnosis of measles. After an extensive regional search and investigation of the six patients' 4,000 contacts, no additional cases were identified. The hospital reviewed employee health records to identify any exposed personnel who did not have serologic evidence of measles immunity. Among 168 potentially exposed employees, 72 (43%) had no documented measles immunity, thus requiring serologic testing and subsequent vaccination if they lacked serologic evidence of immunity. This outbreak highlights the potential for measles transmission in health-care settings. To decrease transmission, clinicians should know the signs and symptoms of measles, request travel histories of patients suspected of any infectious disease, and isolate potentially infectious patients. Hospital employees should have documented immunity to measles, and employees without evidence of measles immunity should be offered vaccination in accordance with Advisory Committee on Immunization Practices (ACIP) and Hospital Infection Control Practices Advisory Committee (HICPAC) recommendations.     

Mumps outbreak in Israel's highly vaccinated society: are two doses enough?

Mumps outbreaks in recent years have given rise to questions about the effectiveness of the mumps vaccine. This study examined the epidemiological data from a recent mumps outbreak in Israel and from outbreaks in other countries with high vaccination coverage, and considered whether long-established vaccination policies designed to protect against mumps are in need of revision. Of over 5000 case patients in the Israeli outbreak, half of whom were in the Jerusalem health district, nearly 40% were aged ≥15 years and, of those whose vaccination status was known, 78% had been fully vaccinated for their age - features similar to those in recent mumps outbreaks in Europe and North America. The epidemiological and laboratory evidence suggests that many previously vaccinated adolescents and young adults are now susceptible to mumps because their vaccine-based immunity has waned. Booster vaccination programmes for those at high risk of infection during mumps outbreaks - particularly those in congregate living environments - merit priority consideration.     

一起寄宿制学校流行性腮腺炎暴发调查

目的 了解该起学校流行性腮腺炎疫情流行特征,查找传播的危险因素,为制定防控措施提供依据。 方法 采用调查登记表开展病例个案调查,运用描述流行病学方法分析疫情流行特征和流行因素。 结果 该起学校流行性腮腺炎疫情历时167天,共发现病例208例,波及24个班级,罹患率为16.98%(208/1 225);10月13日以后每两个发病高峰相距时间范围约为17~18天,且一个峰比一个峰高;不同班级混住的宿舍学生发生流行性腮腺炎病例的危险是无混住现象宿舍学生的1.48倍(95%CI:1.10~2.01);有53.40%(55/103)的病例在发病当天被发现,74.76%(77/103)的病例在发现当天被隔离,45.63%(47/103)的病例发病当天被隔离,隔离时间≥9天的病例占65.05%(67/103)。 结论 病例发现和隔离不及时可导致流行性腮腺炎暴发疫情的扩散和蔓延;不同班级混住是寄宿制学校流行性腮腺炎暴发疫情扩散的危险因素之一。     

Mumps vaccine effectiveness and risk factors for disease in households during an outbreak in New York City

Background and objectives

Mumps outbreaks have been reported among vaccinated populations, and declining mumps vaccine effectiveness (VE) has been suggested as one possible cause. During a large mumps outbreak in New York City, we assessed: (1) VE of measles-mumps-rubella vaccine (MMR) against mumps and (2) risk factors for acquiring mumps in households.

Methods

Cases of mumps were investigated using standard methods. Additional information on disease and vaccination status of household contacts was collected. Case households completed follow-up phone interviews 78–198 days after initial investigation to ascertain additional cases. Mumps cases meeting the study case definition were included in the analysis. Risk factors for mumps were assessed, and VE was calculated using secondary household attack rates.

Results

Three hundred and eleven households with 2176 residents were included in the analysis. The median age of residents was 13 years (range <1–85), and 462 (21.2%) residents met the study mumps case definition. Among 7–17 year olds, 89.7% received one or more doses of MMR vaccine, with 76.7% receiving two doses. Young adults aged 10–14 years (OR = 2.4, CI = 1.3–4.7) and 15–19 years (OR = 2.5, CI = 1.3–5.0) were at highest risk of mumps. The overall 2-dose VE for secondary contacts aged five and older was 86.3% (CI 63.3–94.9).

Conclusions

The two-dose effectiveness of MMR vaccine against mumps was 86.3%, consistent with other published mumps VE estimates. Many factors likely contributed to this outbreak. Suboptimal MMR coverage in the affected population combined with VE may not have conferred adequate immunity to prevent transmission and may have contributed to this outbreak. Achieving high MMR coverage remains the best available strategy for prevention of mumps outbreaks.     

Mumps vaccination coverage and vaccine effectiveness in a large outbreak among college students--Iowa, 2006

Following implementation of a routine childhood two-dose measles-mumps-rubella vaccination strategy, mumps disease levels dropped dramatically in the US and an elimination goal was set for 2010. However, a 2006 epidemic involved >5700 cases nationwide, with many reported among fully vaccinated college students. In an outbreak in two Iowa colleges, we investigated: (1) vaccination coverage using electronic records verified by provider records and (2) vaccine effectiveness assessed by comparison of dose-specific attack rates. Mumps was classified as typical (parotitis/orchitis) or atypical (parotid tenderness or submandibular/sublingual adenitis). Two-dose mumps vaccination coverage was 90% both for the student population (2128/2363) and case-students (97/108). Two-dose vaccine effectiveness was 76-88% with no significant difference for attack rates between one and two doses. Among two-dose vaccine recipients, 74% of the population (1482/2009) and 79% of the case-students (75/95) had received the second dose >10 years before. A large mumps outbreak occurred despite high two-dose vaccination coverage in a population most of whom had received the second dose >10 years before. Two-dose vaccine effectiveness was similar to previous one-dose estimates. Further studies are needed to examine the persistence of two-dose mumps vaccine-induced immunity and to determine whether US mumps elimination can be achieved with the current vaccination strategy.     

Mumps vaccine effectiveness in primary schools and households, the Netherlands, 2008

To estimate the mumps vaccine effectiveness (VE) during a large genotype D mumps outbreak, we conducted a cross-sectional study in eight primary schools and associated households in the Netherlands. Questionnaires were used to collect information on the occurrence of mumps. Multivariate analyses were used to estimate VE. Among schoolchildren we estimated the VE against mumps. Among household contacts where the schoolchild was the index case we estimated the VE against mumps and against mumps infectiousness. In total 1175 children and 2281 household contacts participated in the study. The mumps attack rate among schoolchildren was 17%. The mumps VE in schoolchildren was 92% [95% confidence interval (CI) 83-96%] and 93% [85-97%] for one and two doses of the measles, mumps, rubella (MMR) vaccine, respectively. The adjusted mumps VE among household contacts was 67% [65-95%] and 11% [-4 to 88%] against mumps and mumps infectiousness, respectively. Our study indicates that the mumps component of the MMR vaccine offered adequate protection against mumps among schoolchildren. The relatively low VE among household contacts is of concern.     

Mumps outbreak at a summer camp--New York, 2005

On July 26, 2005, the Sullivan County Health Department (SCHD) and the New York State Department of Health (NYSDOH) were notified of a cluster of cases of parotitis among campers and staff members at a summer camp. An investigation conducted by NYSDOH identified 31 cases of mumps, likely introduced by a camp counselor who had traveled from the United Kingdom (UK) and had not been vaccinated for mumps. This report summarizes the results of the subsequent investigation by NYSDOH, which determined that, even in a population with 96% vaccination coverage, as was the case with participants in the summer camp, a mumps outbreak can result from exposure to virus imported from a country with an ongoing mumps epidemic.     

Seroprotection to vaccine‐preventable diseases among workers at a Victorian tertiary hospital

Objective : To determine seroprotection for the vaccine‐preventable diseases (VPDs) measles, mumps, rubella, varicella and hepatitis B among new employees seen at a Victorian tertiary hospital staff clinic. Methods : Employees who presented to the staff clinic for immunisation assessment between 1 January 2012 and 31 December 2013 were included. Demographic data, self‐reported disease history and previous vaccination status were reviewed retrospectively to determine impact on serological results. Results : A total of 1,901 new employees were included, 83% of whom were at risk of direct contact with blood or body substances. Overall, the proportion of workers seropositive to measles was 88%, mumps 90%, rubella 78%, varicella 93% and hepatitis B 80%. Staff born before 1966 were more likely to have positive measles or mumps serology but negative rubella or hepatitis B serology (p<0.05 for each). Staff who self‐reported measles (99% vs. 93%, p=0.03) or varicella infection (98% vs. 92%, p<0.001) were more likely to be seropositive, but those reporting previous vaccination to measles, mumps or rubella were no more likely to be seropositive. Conclusions and implications : This study demonstrated levels of seropositivity of 78–93% for the five VPDs. Despite recognised limitations of serological testing, 10–20% of new employees to a healthcare institution lacking seroprotection represents a potentially unacceptable risk of nosocomial transmission of these VPDs. Our findings support ongoing serological testing of new healthcare staff at risk of direct contact with blood or body substances.     

Two patients with mumps

Two patients, men aged 17 and 19 years respectively, were admitted with parotitis epidemica and orchitis caused by mumps. The second patient also had meningitis. PCR analysis revealed that, in both cases, the causative agentwas a mumps virus that was genetically related to a wild-type virus responsible for an outbreak in Singapore. This viral strain was also responsible for a mumps outbreak at Hotel School The Hague in September 2004. Both patients were not fully vaccinated. Both patients were from regions in which clustering of patients with clinical signs of mumps has been seen. Interestingly, a number of patients with confirmed mumps had been fully vaccinated. Possible explanations for the increase in mumps cases include low vaccination and immunity levels, primary and secondary vaccine failure and the emergence of genetically disparate mumps viruses.     

Prevalence of measles, rubella, mumps, and varicella antibodies among healthcare workers in Japan.

OBJECTIVES: To evaluate the immune status of healthcare workers (HCWs) against measles, rubella, mumps, and varicella in Japan, and to promote an adequate vaccination program among HCWs. SETTING: University of Tokyo Hospital. PARTICIPANTS: Eight hundred seventy-seven HCWs. DESIGN: Serologic screening for measles, rubella, mumps, and varicella was performed on HCWs. Antibodies against measles, rubella, and mumps were detected using hemagglutination inhibition (HI) assay ($4.20 per test). If serum was negative by HI assay, enzyme-linked immunosorbent assay (EIA) was performed ($12.60 per test). Anti-varicella antibodies were detected by EIA only. RESULTS: Among tested HCWs, 98.5%, 90.4%, 85.8%, and 97.2% had immunity to measles, rubella, mumps, and varicella, respectively. All those born before 1970 were seropositive for measles. However, individuals susceptible to rubella, mumps, and varicella were present in all age groups. The sensitivities and negative predictive values of HI assay compared with EIA were 86.6% and 11.3% for measles, 99.1% and 92.2% for rubella, and 47.8% and 24.1% for mumps, respectively. For measles and mumps, prevaccination screening by HI assay in combination with EIA led to significant savings compared with EIA only. In contrast, it was estimated that prevaccination screening using only HI assay would be more economical for rubella. CONCLUSIONS: Aggressive screening and vaccination of susceptible HCWs was essential regardless of age. Prevaccination serologic screening using a combination of HI assay and EIA was more economical for measles and mumps.     

Brief report: update: mumps activity--United States, January 1-October 7, 2006

During January 1-October 7, 2006, a total of 45 states and the District of Columbia reported 5,783 confirmed or probable mumps cases to CDC. This includes 2,597 cases previously reported by 11 states during January 1-April 29, 2006. This report summarizes the epidemiology of mumps cases in the United States during 2006. With low levels of reported mumps continuing, health-care workers should remain alert to suspected mumps, conduct appropriate laboratory testing, and use every opportunity to ensure adequate immunity, particularly among populations at high risk for mumps.     

Are they protected? Immunity to vaccine‐preventable diseases in healthcare workers at an Australian hospital

Objective : Australian guidelines for healthcare worker (HCW) vaccination were updated in 2010, and pre‐employment assessment of new employees has previously been identified as a priority. We determined the vaccination status of a cohort of existing HCWs at a tertiary hospital in Melbourne, Victoria. Methods : Random sampling of HCWs employed prior to 2006 with unknown/incomplete immunisation status was conducted between April and August 2011. Immunity to vaccine‐preventable diseases (VPDs) was determined serologically (hepatitis B, varicella, measles, mumps, rubella) and by questionnaire (diphtheria, tetanus and pertussis), with vaccination by a nurse immuniser. Results : Overall, 95 HCWs were evaluated. Mean age and duration of employment were 47.2 and 12.6 years, respectively. Forty‐seven staff (49%) required vaccination to comply with Australian immunisation guidelines: 18% were non‐immune to hepatitis B, 2% to varicella, 8% to measles, 19% to mumps and 13% to rubella. HCWs without serological hepatitis B immunity were all staff with clinical roles. Total costs were $7,527.34 (mean $222.79/HCW). Conclusions : Immunity to VPDs among existing HCWs was inadequate. About half assessed HCWs were non‐immune to at least one VPD, and non‐immunity to hepatitis B was high. A comprehensive assessment strategy for existing employees is required to enhance vaccination coverage and compliance with national guidelines. Implications : Adequately resourced ‘look‐back’ immunisation assessment programs are required to reduce the risks of VPDs among existing staff and patients. Review of current approaches and national consensus regarding the need for mandatory strategies would assist this process.     

The effectiveness of the mumps component of the MMR vaccine: a case control study

In 1998/1999, an outbreak of mumps occurred among children of a religious community in North East London. A case control study was conducted to assess the effectiveness of the mumps component of the MMR vaccine. One hundred and sixty-one cases of mumps were identified and 192 controls were selected. Fifty-one percent of cases and 77% of controls had a history at least one MMR vaccination. The observed effectiveness of any MMR vaccination adjusted for age, sex and general practice was 69% (95% CI: 41-84%). This is consistent with the results of other observational studies of mumps containing vaccines, but lower than the immunogenicity of mumps vaccines reported by clinical trials. This discrepancy is because observational studies tend to underestimate vaccine effectiveness, and because immunogenicity is not necessarily an accurate biological marker of vaccine effectiveness. Two doses of vaccine were more effective (88% (95% CI: 62-96%)) than a single dose (64% (95% CI: 40-78%)). The current two-dose vaccination programme remains the best method for controlling mumps infection in the community.     

2001-2013年重庆市九龙坡区流行性腮腺炎流行特征和暴发疫情分析

目的了解重庆市九龙坡区流行性腮腺炎流行病学特征,为控制流行提供依据。方法采用描述流行病学方法,分析重庆市九龙坡区2001~2013年流行性腮腺炎发病及其分布情况。结果2001~2013年重庆市九龙坡区报告发生流行性腮腺炎共6560例,年均发病率59.91／10万,无死亡,其中2006~2013年发生暴发疫情共17起537例,罹患率2.56%;发病呈周期性升高,形成2004年和2010年两个高峰年,发病率分别为139.73／10万、135.27／10万,发病有明显季节性,4~7月份占全年发病总数的58.35％;农村高于城市,城乡发病率之比为1：l.54,差异有显著性意义(χ²=285.92,P<0.01);人群分布以15岁以下儿童为主占86.63％,其中5~9岁年龄组的发病数最高占46.42%;男性发病高于女性,男女之比为1.32：1,差异有显著性意义(χ²=121.84,P<0.01)。结论2001~2013年重庆市九龙坡区流行性腮腺炎发病呈周期性升高,近年来暴发疫情居九龙坡区中小学校首位, 乡级小学是暴发的主要场所,应加强流行性腮腺炎监测和疫苗接种工作,提高人群免疫水平,从根本上减少腮腺炎发病。