Laboratory diagnosis of mumps in a partially immunized population: The Nova Scotia experience

What is the relevancy of a surveillance of mumps without a systematic laboratory confirmation in highly immunized populations? Epidemiology of suspected and biologically confirmed mumps cases seen in general practice in France between 2014 and 2020

BACKGROUND

In France, mumps surveillance is conducted in primary care by the Sentinelles network, the National Reference Centre for Measles, Mumps and Rubella and Santé publique France.

AIM

The objective of this study was to estimate the incidence of suspected mumps in general practice, the proportion of laboratory confirmed cases and the factors associated with a virological confirmation.

METHODS

General practitioners (GPs) participating in the Sentinelles network should report all patients with suspected mumps according to a clinical definition in case of parotitis and a serological definition in case of clinical expression without parotitis. All suspected mumps cases reported between January 2014 and December 2020 were included. A sample of these cases were tested by real time reverse transcriptase polymerase chain reaction (RT-PCR) for mumps biological confirmation.

RESULTS

A total of 252 individuals with suspected mumps were included in the study. The average annual incidence rate of suspected mumps in general practice in France between 2014 and 2020 was estimated at 11 cases per 100,000 population [CI95%: 6-17]. A mumps confirmation RT-PCR test was performed on 146 cases amongst which 17 (11.5 %) were positive. Age (between 20 and 29 years old), the presence of a clinical complication and an exposure to a suspected mumps case within the 21 days prior the current episode were associated with a mumps biological confirmation.

CONCLUSION

If these results confirm the circulation of mumps virus in France, they highlight the limits of a surveillance without a systematic laboratory confirmation in highly immunized populations.

An individual level infectious disease model in the presence of uncertainty from multiple, imperfect diagnostic tests

Bayesian compartmental infectious disease models yield important inference on disease transmission by appropriately accounting for the dynamics and uncertainty of infection processes. In addition to estimating transition probabilities and reproductive numbers, these statistical models allow researchers to assess the probability of disease risk and quantify the effectiveness of interventions. These infectious disease models rely on data collected from all individuals classified as positive based on various diagnostic tests. In infectious disease testing, however, such procedures produce both false-positives and false-negatives at varying rates depending on the sensitivity and specificity of the diagnostic tests being used. We propose a novel Bayesian spatio-temporal infectious disease modeling framework that accounts for the additional uncertainty in the diagnostic testing and classification process that provides estimates of the important transmission dynamics of interest to researchers. The method is applied to data on the 2006 mumps epidemic in Iowa, in which over 6,000 suspected mumps cases were tested using a buccal or oral swab specimen, a urine specimen, and/or a blood specimen. Although all procedures are believed to have high specificities, the sensitivities can be low and vary depending on the timing of the test as well as the vaccination status of the individual being tested.

Mumps virus outbreak related to a water pipe (narghile) shared smoking

INTRODUCTION

This study describes a mumps outbreak among a group of young people who shared a same narghile to smoking. Saliva and blood samples were obtained from 3 cases for RT-PCR and serology respectively.

METHODS

The notification of a mumps case started an epidemiological investigation. Information of other 6 additional symptomatic persons who had gathered with the case in a discotheque where they smoking in a same narghile was achieved. RT-PCR positive samples were genotyped by sequencing.

RESULTS

The 7 patients resided in 3 different municipalities, and they do not have get together for more than a month until the meeting in the discotheque. Four cases were confirmed by RT-PCR and/or IgM determinations. The genomic investigation showed identical nucleic sequences.

CONCLUSIONS

This outbreak is consequence of the common use of a narghile to smoking. The public usage of these water pipes should be regulated.

Effectiveness of an outbreak dose of mumps-containing vaccine in two First Nations communities in Northern Ontario, Canada

Between 18 Dec 2017 and 27 June 2018, a mumps outbreak occurred in two Canadian Indigenous communities. An outbreak dose of mumps-containing vaccine was offered as part of control measures. We conducted a cohort study and survival analysis to describe the outbreak and evaluate the outbreak dose, extracting vaccination information on all community members (n = 3,135) from vaccination records. There were 70 mumps cases; 56% had received two pre-outbreak vaccine doses. Those who received a pre-outbreak dose more distantly had higher rates of mumps compared to those with more recent doses (adjusted hazard ratio = 3.4 (95%CI: 0.7–20.6) for receipt >20 years before vs. receipt ≤3 years). During the outbreak, 33% (1,010/3,080) of eligible individuals received an outbreak dose. The adjusted hazard ratio for no outbreak dose receipt was 2.7 (95%CI: 1.0–10.1). Our results suggest that an outbreak dose of mumps-containing vaccine may be an effective public health intervention, but further study is warranted.

Acute Appearance of a Neck Mass in an 11-Year-Old Girl

Pustular abscess formation in the parotid gland is a rare complication following mumps virus infection. This is the second case report of pediatric parotid pustular abscess accompanied with mumps virus infection. Continuous antibiotics prescription without surgery is an eligible treatment for this patient.

Mumps virus outbreak related to a water pipe (narghile) shared smoking

INTRODUCTION

This study describes a mumps outbreak among a group of young people who shared a same narghile to smoking. Saliva and blood samples were obtained from 3cases for RT-PCR and serology respectively.

METHODS

The notification of a mumps case started an epidemiological investigation. Information of other 6additional symptomatic persons who had gathered with the case in a discotheque where they smoking in a same narghile was achieved. RT-PCR positive samples were genotyped by sequencing.

RESULTS

The 7patients resided in 3different municipalities, and they do not have get together for more than a month until the meeting in the discotheque. Four cases were confirmed by RT-PCR and/or IgM determinations. The genomic investigation showed identical nucleic sequences.

CONCLUSIONS

This outbreak is consequence of the common use of a narghile to smoking. The public usage of these water pipes should be regulated.

Mumps Outbreaks in Vaccinated Populations-Is It Time to Re-assess the Clinical Efficacy of Vaccines?

History illustrates the remarkable public health impact of mass vaccination, by dramatically improving life expectancy and reducing the burden of infectious diseases and co-morbidities worldwide. It has been perceived that if an individual adhered to the MMR vaccine schedule that immunity to mumps virus (MuV) would be lifelong. Recent mumps outbreaks in individuals who had received two doses of the Measles Mumps Rubella (MMR) vaccine has challenged the efficacy of the MMR vaccine. However, clinical symptoms, complications, viral shedding and transmission associated with mumps infection has been shown to be reduced in vaccinated individuals, demonstrating a benefit of this vaccine. Therefore, the question of what constitutes a good mumps vaccine and how its impact is assessed in this modern era remains to be addressed. Epidemiology of the individuals most affected by the outbreaks (predominantly young adults) and variance in the circulating MuV genotype have been well-described alluding to a collection of influences such as vaccine hesitancy, heterogeneous vaccine uptake, primary, and/or secondary vaccine failures. This review aims to discuss in detail the interplay of factors thought to be contributing to the current mumps outbreaks seen in highly vaccinated populations. In addition, how mumps diagnoses has progressed and impacted the understanding of mumps infection since a mumps vaccine was first developed, the limitations of current laboratory tests in confirming protection in vaccinated individuals and how vaccine effectiveness is quantified are also considered. By highlighting knowledge gaps within this area, this state-of-the-art review proposes a change of perspective regarding the impact of a vaccine in a highly vaccinated population from a clinical, diagnostic and public perspective, highlighting a need for a paradigm shift on what is considered vaccine immunity.

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.

Post-mumps acute disseminated encephalomyelitis in an adolescent

Mumps is an acute communicable self-limiting swelling of the parotid or other salivary glands. Various organs can be involved including the testes, central nervous system, mammary glands, ovary, pancreas, kidneys, and heart. We hereby present a rare case of an 18-year-old unvaccinated male with acute disseminated encephalomyelitis following mumps without parotitis.

Laboratory testing and phylogenetic analysis during a mumps outbreak in Ontario, Canada

BACKGROUND

In September 2009, a mumps outbreak originated in New York and spread to Northeastern USA and Canada. This study compares the performance of different diagnostic testing methods used in Ontario and describes molecular characteristics of the outbreak strain.

METHODS

Between September 2009 and February 2010, specimens from suspect cases were submitted to Public Health Ontario Laboratory for mumps serology, culture and/or real-time reverse-transcriptase PCR (rRT-PCR) testing. rRT-PCR-positive specimens underwent genotyping at Canada's National Microbiology Laboratory. Whole genome sequencing was performed on four outbreak and three sporadic viral culture isolates.

RESULTS

Six hundred ninety-eight patients had IgM serology testing, of which 255 (37%) had culture and rRT-PCR. Among those, 35/698 (5%) were IgM positive, 39/255 (15%) culture positive and 47/255 (18%) rRT-PCR-positive. Buccal swabs had the highest rRT-PCR positivity (21%). The outbreak isolates were identical to that in the New York outbreak occurring at the same time. Nucleotide and amino acid identity with the Jeryl Lynn vaccine strain ranged from 85.0-94.5% and 82.4-99.4%, depending on the gene and coding sequences. Homology of the HN protein, the main immunogenic mumps virus protein, was found to be 94.5 and 95.3%, when compared to Jeryl Lynn vaccine major and minor components, respectively.

CONCLUSIONS

Despite higher sensitivity than serology, rRT-PCR testing is underutilized. Further work is needed to better understand the suboptimal match of the HN gene between the outbreak strain and the Jeryl Lynn vaccine strain.

Diagnostic Yield of Laboratory Methods and Value of Viral Genotyping during an Outbreak of Mumps in a Partially Vaccinated Population in British Columbia, Canada

Mumps remains endemic in North America despite routine use of the measles, mumps, and rubella (MMR) vaccine. In 2016, an outbreak of mumps in British Columbia, Canada, provided an opportunity to determine the diagnostic utility of laboratory testing methods. Specimens from patients with clinical mumps were tested for infection using a commercial enzyme-linked immunosorbent assay (ELISA) for antibody detection and an in-house reverse transcriptase PCR (RT-PCR) targeting viral fusion and small hydrophobic (SH) genes. Viral genotyping was performed by SH gene sequencing. Laboratory data was linked with epidemiologic case data. Of the 139 confirmed cases, 94 (68%) had reported or documented history of MMR vaccination. Specimens were typically collected 1 day (for buccal and IgM tests) or 2 days (for urine tests) after symptom onset. Most confirmed cases (69%) were confirmed by buccal swab RT-PCR. Among cases tested by multiple methods, the percent positivity for buccal swab RT-PCR was 90% (96/107) compared to 43% (30/69) for both IgM ELISA and urine RT-PCR. Mumps IgM detection was higher in confirmed cases with no history of vaccination than in those with history (64% versus 34%, P = 0.02). The outbreak strain was identified as genotype G related to MuVi/Sheffield.GBR/1.05 but with conserved variations in five nucleotides within the SH gene that allowed linkage of geographically distinct cases. In conclusion, RT-PCR of buccal specimens had the highest diagnostic yield during a mumps outbreak in a partially vaccinated population. To optimize mumps diagnostic potential, clinicians should collect specimens depending on when the patient presents for care and their immunization history.

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.

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

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

Serological diagnosis of mumps: Value of the titration of specific IgG

INTRODUCTION

The aim of this study was to evaluate a cut-off point of the titration of IgG by ELISA in the diagnosis of mumps.

METHODS

A study was made of serum samples from 85 mumps cases (confirmed by PCR in saliva) and 2,351 controls of the general population of the Region of Madrid.

RESULTS

The IgM detection was positive in 21 cases (sensitivity of 24.7%). The best cut-off point corresponded to IgG titres ≥4,900 (sensitivity of 64.7% and specificity of 86.1%). Among 42 patients immunised with at least one dose of measles mumps, rubella vaccine IgM was detected in 4 cases. However, the detection of IgG ≥4,900 was positive in 29 (sensitivity of 69.0%).

CONCLUSIONS

An IgG result of ≥4.900 was almost 5 times more probable in a patient with mumps than in a non-infected patient. The detection of high titres of IgG against mumps could improve the IgM results in vaccinated people.

Laboratory-based investigation of suspected mumps cases submitted to the German National Reference Centre for Measles, Mumps, and Rubella, 2008 to 2013

From 2008 to 2013, sample sets from 534 patients displaying clinical symptoms of mumps were submitted to the German Reference Centre for Measles, Mumps and Rubella. Mumps virus infection was confirmed in 216 cases (40%) by PCR and/or serology. Confirmed cases were more frequently seen in male than in female patients (128 vs. 81); the age group predominantly affected was 15 to 29 years old (65%, median age: 26.4 years). The majority of the confirmed cases had a remote history of vaccination with one or two doses of a mumps-containing vaccine (69%). Our results indicate that mumps virus caused two outbreaks in Bavaria in 2008 and 2010/2011 and a third one in Lower Saxony in 2011. Mumps virus genotype G was preponderantly detected from 2008 to 2013. For 107 of the 216 patients with a confirmed mumps infection, we correlated the results from PCR and serology. PCR detected cases during the first week after onset of symptoms (74% positive results). PCR worked best with throat swabs and oral fluids (61% and 60% positive results, respectively). IgM was more reliable with a longer time after onset of symptoms (67%), but indirect IgM serology was of insufficient sensitivity for vaccinated mumps cases (30%); the IgM μ-capture assay detected more cases in this group. Mumps virus is able to initiate an infection in vaccinated patients (secondary vaccine failure, SVF) although it is unclear to what extent. Since SVF does occur in highly vaccinated populations and IgM will not increase to detectable levels in all SVF patients, we strongly recommend using PCR plus serology tests to avoid false-negative diagnoses in vaccinated individuals with clinical signs of mumps.

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

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

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.

Measles, mumps, rubella, and human parvovirus B19 infections and neurologic disease

While the systemic disorders associated with measles, mumps, and rubella viruses and human parvovirus B19 tend to be mild, each virus can produce potentially life-threatening neurologic disease in human hosts, especially when these viruses infect young children. Two of the viruses, rubella and parvovirus B19, can be vertically transmitted to fetuses during maternal infection and cause congenital infection. Neurologic complications are common after intrauterine infection with the rubella virus, a condition known as the congenital rubella syndrome. Two, measles and rubella viruses, can induce "slow viral" infections, serious, disorders that can occur several years after the initial exposure to the virus and typically have fatal outcomes.

Comparison of the sensitivity of laboratory diagnostic methods from a well-characterized outbreak of mumps in New York city in 2009

A mumps outbreak in upstate New York in 2009 at a summer camp for Orthodox Jewish boys spread into Orthodox Jewish communities in the Northeast, including New York City. The availability of epidemiologic information, including vaccination records and parotitis onset dates, allowed an enhanced analysis of laboratory methods for mumps testing. Serum and buccal swab samples were collected from 296 confirmed cases with onsets from September through December 2009. All samples were tested using the Centers for Disease Control and Prevention (CDC) capture IgM enzyme immunoassay (EIA) and a real-time reverse transcription-PCR (rRT-PCR) that targets the short hydrophobic gene. A subset of the samples (n = 205) was used to evaluate 3 commercial mumps IgM assays and to assess the sensitivity of using an alternative target gene (nucleoprotein) in the rRT-PCR protocol. Among 115 cases of mumps with 2 documented doses of measles, mumps, and rubella (MMR) vaccine, the CDC capture IgM EIA detected IgM in 51% of serum samples compared to 9% to 24% using three commercial IgM assays. The rRT-PCR that targeted the nucleoprotein gene increased RNA detection by 14% compared to that obtained with the original protocol. The ability to detect IgM improved when serum was collected 3 days or more after symptom onset, whereas sensitivity of RNA detection by rRT-PCR declined when buccal swabs were collected later than 2 days after onset. Selection of testing methods and timing of sample collection are important factors in the ability to confirm infection among vaccinated persons. These results reinforce the need to use virus detection assays in addition to serologic tests.

Differentiating the wild from the attenuated during a measles outbreak

In the midst of a local measles outbreak, a recently immunized child was investigated for a new-onset measles-type rash. Nucleic acid testing identified that a vaccine-type measles virus was being shed in the urine. Clinically differentiating measles from a nonmeasles rash is challenging, but can be supported by a thorough medical history evaluation. Rashes are expected to occur after immunization; nucleic acid testing can be used when it is difficult to differentiate between wild and attenuated strains.

Difficulty with mumps diagnosis: what is the contribution of mumps mimickers?

BACKGROUND

Mumps is a vaccine preventable disease that typically presents with unilateral or bilateral parotitis. In February 2007, mumps re-emerged in university students in Nova Scotia. Despite highly sensitive methods for mumps virus detection, only 14% (298/2082) of cases during the peak of the outbreak were laboratory confirmed.

OBJECTIVES

Due to the low positivity rate, this study investigated whether infection with other viral pathogens caused mumps-like presentations during the outbreak.

STUDY DESIGN

148 buccal specimens from patients who presented with unilateral or bilateral parotitis but had negative laboratory tests for mumps virus were tested for Epstein-Barr virus (EBV) and cytomegalovirus (CMV) by quantitative PCR and 21 different viral markers using the Luminex xTAG Respiratory Virus Panel (RVP). Companion sera to each buccal specimen were available for EBV and CMV serology to differentiate acute infection from reactivation.

RESULTS

No correlation was observed since viral pathogens were detected in both the parotitis and non-parotitis groups.

CONCLUSION

Although there was co-circulation of other viral pathogens during the mumps outbreak, no difference was observed in the prevalence between patients who presented with or without parotitis. The low positivity rate for specimens submitted for mumps diagnostics was likely the result of increased Public Health messaging and physician inexperience in recognizing mumps infection, suggesting the clinical acumen for mumps diagnosis based solely on clinical presentation is low.