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.

Management and control of communicable diseases in schools and other child care settings: systematic review on the incubation period and period of infectiousness

Background

Information on the incubation period and period of infectiousness or shedding of infectious pathogens is critical for management and control of communicable diseases in schools and other childcare settings.

Methods

We performed a systematic literature review (Pubmed and Embase) to identify and critically appraise all relevant published articles using incubation, infectiousness or shedding, and exclusion period as parameters for the search. No language, time, geographical or study design restrictions were applied.

Results

A total of 112 articles met the eligibility criteria. A relatively large number were retrieved for gastrointestinal diseases and influenza or respiratory syncytial virus, but there were few or no studies for other diseases. Although a considerable number of publications reported the incubation and shedding periods, there was less evidence concerning the period of infectiousness. On average, five days of exclusion is considered for measles, mumps, rubella, varicella and pertussis. For other diseases, such as most cases of meningococcal disease, hepatitis A and influenza exclusion is considered as long as severe symptoms persist. However, these results are based on a diverse range of study characteristics, including age, treatment, vaccination, underlying diseases, diagnostic tools, viral load, study design and definitions, making statistical analysis difficult.

Conclusions

Despite inconsistent definitions for key variables and the diversity of studies reviewed, published data provide sufficient quantitative estimates to inform decision making in schools and other childcare settings. The results can be used as a reference when deciding about the exclusion of a child with a communicable disease that both prevents exposure and avoids unnecessary absenteeism.

Mumps outbreaks: A problem in need of solutions

OBJECTIVES

To discuss what is presently known about recent mumps outbreaks and what solutions can be suggested to ensure more complete protection against mumps.

METHODS

PubMed was used to search for all of the studies published over the last 15 years using the key words "mumps" or "mumps virus" or "mumps vaccine". More than 1500 articles were found, but only those published in English or providing evidence-based data were included in the evaluation.

RESULTS

Prevention of mumps remains an unsolved problem. Available vaccines are effective but the protection they evoke declines over time. The use of booster doses can control outbreaks but it is not precisely defined whether they can prevent them. The rapid decline of antibody levels could limit the impact of the introduction of a third dose in the recommended immunization schedule. Furthermore, in most of the areas, mumps viral strains that are genetically different from those included in the vaccines are emerging and this might favour vaccine escape. However, also for this problem, its real relevance in favouring outbreak development is not precisely defined.

CONCLUSIONS

The true reasons for the development of mumps outbreaks in people with very high vaccination coverage are not clearly understood. The use of a booster dose or the preparation of vaccines containing the emerging serotypes are possible solutions, but both have some limitations. Further studies mainly devoted to improve our knowledge of the immune response to mumps vaccines are needed before long-term effective mumps vaccines can be prepared and outbreaks can be avoided.

Mumps disease in Beijing in the era of two-dose vaccination policy, 2005-2016

BACKGROUND

Since the introduction of mumps-containing vaccines (MuCV) in 1995 in Beijing, two-dose MuCV vaccination policy has been used, with the 1st and 2nd doses given at 18 months and 6 years of age, respectively.

METHODS

Mumps epidemiology during 2005-2016 was described using surveillance data. Vaccine effectiveness (VE) of MuCV against disease was estimated for cases born during 2002-2009 and reported in 2016. VE against complications was estimated for all cases. MuCV coverage was estimated for children born during 1999-2015 using data from Beijing Immunization Information System.

RESULTS

Overall mumps incidence decreased from 30.38/100,000 persons in 2005 to 10.26/100,000 persons in 2016. Incidence declines in children aged <15 years. No significant incidence change occurred in adults aged ≥20 years. Incidence in persons aged 15-19 years increased by 132.73% in 2012 when compared with in 2005. Rates of meningitis/encephalitis, orchitis, and other complications among cases decreased during 2005-2016. The majority (97%) of outbreaks occurred in schools. Total number of outbreaks and average outbreak size decreased during 2005-2016. Among outbreak-related cases, 69.54%, 29.67% and 0.79% had received 0 dose, 1dose and 2 doses of MuCV, respectively. Coverage of the 1st MuCV dose at 2-5 years of age increased by 42.75% during 2005-2016. Coverage of the 2nd MuCV dose at 6-14 years of age increased by 12.87% during 2013-2016. Overall VE estimates of MuCV against mumps disease were 74.51% (95% CI: 65.57-81.34%) for 1 dose and 83.16% (95% CI: 78.60-86.31%) for 2 doses. Both VE estimates increased by birth cohorts. VE estimate against complications for 2-dose MuCV was higher than for 1 dose.

CONCLUSIONS

Increasing MuCV coverage achieved declining mumps incidence and complication rate. Current epidemiology supported 2-dose MuCV vaccination policy. The incidence rise in persons aged 15-19 years in 2012 and waning immunity for the 2nd MuCV dose merited close follow-up.

Meteorological factors and the incidence of mumps in Fujian Province, China, 2005-2013: Non-linear effects

BACKGROUND

Mumps is still an important public health issue in the world with several recent outbreaks. The seasonable distribution of the disease suggested that meteorological factors may influence the incidence of mumps. The aim of this study was to explore the possible association between meteorological factors and the incidence of mumps, and to provide scientific evidence to relevant health authorities for the disease control and prevention.

METHODS

We obtained the data of mumps cases and daily meteorological factors in Fujian Province in Eastern China over the period of 2005-2013. Using distributed lag non-linear model (DLNM) approach, we assessed the relationship between the meteorological factors and mumps incidence.

RESULTS

The effects of meteorological factors on the mumps incidence were all non-linear. Compared with the lowest risk values, the upper level of precipitation, atmospheric pressure and relative humidity could increase the risk of mumps, whereas the low level of wind velocity, temperature, diurnal temperature range and sunshine duration may also increase the risk. Moderate atmospheric pressure and low wind velocity had larger cumulative effects within 30lagdays and the relative risks were 10.02 (95%CI: 2.47-40.71) and 12.45 (95%CI: 1.40-110.78). For temperature, the cumulative effect within 30lagdays of minimum temperature was higher than that from maximum temperature in most populations. The cumulative effects of minimum temperature for males, children aged 10-14 and students were higher than those in other populations.

CONCLUSIONS

Meteorological factors, especially temperature and wind velocity, should be taken into consideration in the prevention and warning of possible mumps epidemic. Special attention should be paid to the vulnerable populations, such as teenagers and young adults.

Waning immunity of one-dose measles-mumps-rubella vaccine to mumps in children from kindergarten to early school age: a prospective study

BACKGROUND

In China, one dose measles-mumps-rubella vaccine (MMR) was administered to children aged 18-24 months. The mumps incidence was still high. Data on the waning immunity to mumps after MMR vaccination are limited. This study aimed to describe the waning immunity to mumps in kindergarten and primary school children to provide a scientific basis for confirming an optimal age for a second dose.

METHODS

An observational, prospective study on one-dose MMR in children in kindergarten and primary school was conducted from 2015 to 2016. Waning immunity to mumps in terms of seropositivity and geometric antibody concentration (GMC) with time was analyzed.

RESULTS

In total, 7436 eligible subjects in kindergarten (3435) and primary school (4001) were included in 2015. The overall GMC (201.7 U/ml) and seropositivity (75.4%) to mumps antibodies in 2016 were significantly lower compared to those in 2015 (218.7 U/ml, 78.4%). Asymptomatic infection occurred within one year in 8.8% of children who received one-dose MMR.

CONCLUSIONS

Children who received one-dose MMR in kindergarten and primary school were at high risk of mumps infection, and waning immunity occurred with time. Determining the optimal age for the second dose of MMR in children should be prioritized to prevent mumps epidemics.

Ongoing mumps outbreak in Israel, January to August 2017

In Israel, 262 mumps cases were registered between 1 January and 28 August 2017 despite a vaccine coverage of ≥ 96%. The majority (56.5%) of cases were adolescents and young adults between 10 and 24 years of age. Nearly twice as many cases were reported in males than in females. Sequence information identified genotype G and suggested specific transmission chains in different religious communities, with the Muslim population in Jerusalem being most severely affected.

[Evaluation on the short term effectiveness of two doses mumps-containing vaccine policy in Shandong, China]

Objective: To evaluate the effectiveness of mumps prevention and control after implementation of two doses mumps-containing combined vaccine (MuCV) policy by analyzing epidemiological characteristics of mumps and mumps antibody levels in general population. Methods: We obtained data on cases of mumps reported during 2004-2015 from National Notifiable Diseases Reporting System (NNDRS). Descriptive analysis methods were used to describe the epidemiological characteristics of mumps during 2004-2015. MuCV immunization information from 2005 to 2015 was obtained from the immunization information management system in Shandong Province. Antibody data of mumps in healthy people were from a cross-sectional survey according to the principle of stratified random sampling from 0 to 60 years old healthy people in 2015. Commercial ELISA kits were used to detect and quantify human IgG antibodies against mumps virus in sera, and the results were analyzed statistically. Results: The average incidence of mumps from 2004 to 2015 was 11.43/100 000 in Shandong. The incidence of mumps in the central region (14.64/100 000) was higher than that in the eastern and western regions (11.14/100 000, 11.33/100 000). The incidence of mumps was still high in 2009-2013 (stage of one-dose MuCV free, 16.07/100 000) with the highest incidence of 25.33/100 000 and 24.45/100 000 occurred in 2012 and 2013 and the cases were mainly 6 to 9 years old group (172.67/100 000). Since the second dose MuCV was introduced into NIP for 6 years old children in May 2013 in Shandong, the incidence of mump decreased significantly in 2014-2015 (7.81/100 000), especially in children of 6-8 years old who were vaccinated with two doses of MuCV (2009-2013 was 114.02/100 000; 2014-2015 was 45.66/100 000) and lower than 3-5 years old vaccinated one doses of MuCV. A total of 1 785 serum samples were collected from the healthy population, the average seroprevalence was 80.62% and Geometric Mean Concentration (GMC) was 38.11 IU/ml (95%CI: 37.03-39.19 IU/ml) . There was no significant difference about seroprevalence in different regions, while the GMC in middle region was significantly higher compared to east and west region. The prevalence and GMC in children aged 19 months-2 years and 3-5 years old who received one dose of MuCV were significantly higher than those of <19 months old children. The GMC (46.88 IU/ml, 95%CI: 39.43-55.74 IU/ml) in children aged 6-9 years old who received the two doses MuCV was significantly higher than that of aged 3-5 years old children (31.71 IU/ml, 95%CI: 27.23-36.93 IU/ml). Conclusion: The incidence of mumps in Shandong was still at a high level in spite of coverage one doses MuCV to children. Compared with the period of the 1 dose MuCV immunization strategy, the incidence the groups coverage two doses MuCV was significantly reduced and lower the groups coverage one dose MuCV, but the prevalence and GMC were higher than that of the groups coverage one dose MuCV.

Assessment of mumps-containing vaccine effectiveness during an outbreak: Importance to introduce the 2-dose schedule for China

INTRODUCTION

China has used 3 different mumps-containing vaccines (MuCV) since 1990: monovalent mumps vaccine, measles-mumps (MM) vaccine, and measles-mumps-rubella (MMR) vaccine, and one dose MuCV (using MMR at 18 months) has been included in the EPI since 2007. MuCV effectiveness has been of concern following large-scale mumps outbreaks. In 2015, an outbreak of mumps occurred in a primary school, which allow us assess vaccine effectiveness of different MuCVs.

METHOD

All children in the school were studied as a retrospective cohort. Vaccination histories and case information were obtained from vaccination records and clinic/hospital logs. Parental questionnaires were used to confirm students' illnesses and calculate attack rate (AR). VE was assessed using the formula, VE = (AR in unvaccinated students- AR in the vaccinated students) / (AR in unvaccinated students). VEs of different type of MuCV were compared.

RESULTS

In total, 283 students were identified as clinical mumps among the 2370 students, and 1908 students were included for MuCV VE assessment. 213 (including 21 [8.9%] patients) were 2-dose MuCV recipients (AR: 9.9%), 1165 (including 123 [51.9%] patients) were 1-dose recipients (AR: 10.6%), and 530 (including 93 [39.2%] patients) were unvaccinated (AR: 17.5%). VE was 44% for 2 doses and 40% for one dose. For one-MuCV-dose students, estimated mumps VE was 63% for vaccinated within 3 years (between vaccination and this outbreak); 50% for vaccinated within 3 to 5 years; and 34% for vaccinated more than 5 years. Comparing VE by vaccine type and 5-year interval since vaccination, VE for MMR was 60%, which was consistently higher than VE for monovalent mumps vaccine (22%) and MM (2%).

CONCLUSION

This outbreak was associated with low and declining 1-dose MuCV effectiveness. China's immunization program should evaluate the potential of a 2-dose MMR schedule to adequately control mumps.

Humoral immunity to mumps in a highly vaccinated population in Taiwan

BACKGROUND

A resurgence of mumps was noted recently and outbreaks were increasingly reported in populations with high vaccine coverage. We aimed to evaluate the seroprevalence to mumps in Taiwan, where a two-dose childhood mumps-containing vaccine program, with a high coverage rate, had been implemented for >20 years.

METHODS

The anti-mumps IgG was determined in 3552 participants of all ages in Taiwan. The age-specific seropositivity rates were calculated and the sociodemographic variables associated with the seronegative sera were analyzed with a logistic regression method.

RESULTS

The overall seroprevalence to mumps was 71%, with a higher rate in adults ≥19 years old than in the pediatric population <19 years old (80.4% versus 62.0%, P < 0.0001). In participants aged 2-20 years, who had been given at least one mumps-containing vaccine, the seropositivity fluctuated across different age subgroups and the lowest rate (36.8%) occurred in the 17-18 years age group. The multivariate analysis identified age within 17-18 years (adjusted odds ratio [aOR] 8.598, 95% confidence interval [CI] 2.990-24.722, P < 0.0001), within 19-20 years (aOR 5.076, 95% CI 1.702-15.133, P = 0.0080), and being a resident of the suburban area of northern Taiwan (aOR 1.089, 95% CI 0.823-1.414, P = 0.0008) as independent factors associated with an increased risk of seronegative sera.

CONCLUSION

The seropositivity to mumps was unexpectedly low in highly vaccinated generations, and with a significant geographical discrepancy in Taiwan, which may have been responsible for the sustained reports of mumps cases in Taiwan.

A case of mumps-related acute encephalopathy with biphasic seizures and late reduced diffusion

BACKGROUND

Mumps is a common childhood viral disease characterized by fever and swelling of the parotid gland. The prognosis is generally good, although some complications, such as encephalitis (0.1%), exist. Acute encephalopathy with biphasic seizures and late reduced diffusion is the most common type of acute encephalopathy. However, this type of encephalopathy has not been reported in association with mumps infection.

PATIENT

A previously healthy 3-year-old Japanese boy had a brief convulsion after fever for 3days, and then had conscious disturbance and parotitis. After several days, he had a second brief convulsion and was admitted. Increased serum amylase levels and presence of anti-mumps immunoglobulin M antibody confirmed mumps parotitis. The patient had another brief seizure later the day of admission. He did not have status or cluster seizures, although the biphasic nature of his seizures, conscious disturbance between the seizures, no pleocytosis in cerebrospinal fluid, and brain magnetic resonance images were consistent with acute encephalopathy with biphasic seizures and late reduced diffusion.

DISCUSSION

In Japan, the mumps vaccine is not administered as a part of routine immunizations. It thus has low coverage (30-40%), and as a result, mumps infections are still common. However, this is the first case of mumps-related acute encephalopathy with biphasic seizures and late reduced diffusion. This case may be representative of only a minority of patients with mumps-associated central nervous system involvement. Nevertheless, this diagnostic possibility may be considered. In order to prevent mumps-related complications, routine mumps vaccination might be warranted.

[Application of State Space model in the evaluation of the prevention and control for mumps]

Objective: To analyze the epidemiological characteristics of mumps in 2012 and 2014, and to explore the preventive effect of the second dose of mumps-containing vaccine (MuCV) in mumps in Shandong province. Methods: On the basis of certain model assumptions, a Space State model was formulated. Iterated Filter was applied to the epidemic model to estimate the parameters. Results: The basic reproduction number (R(0)) for children in schools was 4.49 (95%CI: 4.30-4.67) and 2.50 (95%CI: 2.38-2.61) respectively for the year of 2012 and 2014. Conclusions: Space State model seems suitable for mumps prevalence description. The policy of 2-dose MuCV can effectively reduce the number of total patients. Children in schools are the key to reduce the mumps.

Pseudotumoral acute cerebellitis associated with mumps infection in a child

Pseudotumoral cerebellitis in childhood is an uncommon presentation of cerebellitis mimicking a brain tumor. It often follows an inflammatory or infectious event, particularly due to varicella virus. Patients could have a wide clinical spectrum on presentation. Some patients may be asymptomatic or present at most with mild cerebellar signs, whereas others may suffer severe forms with brainstem involvement and severe intracranial hypertension mimicking tumor warranting surgical intervention. Imaging techniques especially multimodal magnetic resonance imaging represent an interesting tool to differentiate between posterior fossa tumors and acute cerebellitis. We describe a case of pseudotumoral cerebellitis in a 6-year-old girl consequent to mumps infection and review the literature on this rare association.

MMR and MMRV vaccines

Measles, mumps, rubella and varicella are viral infections which can implicate seriously long-term sequelae of infected individuals or even the unborn child. Vaccines against the individual diseases have long been available. Global measles vaccination is estimated to have prevented more than 20million deaths during 2000-2015. During the same time period, measles incidence decreased from 146 to 36 cases per million populations. Today vaccinations against measles, mumps, rubella and varicella are now carried out mainly with combination vaccines. These are today known as immunogenic and safe. MMRV had similar immunogenicity and overall safety profiles to MMR administered with or without varicella vaccine. This issue provides a review of the different vaccines, mode of administration, catch up immunization and postexposure prophylaxis as well as contraindications and adverse effects of the immunization against measles, mumps, rubella, and varicella. The article presents an overview of important information of preventing these diseases with a focus on the existing combination vaccines.

Immunogenicity of mumps virus vaccine candidates matching circulating genotypes in the United States and China

Mumps virus (MuV) causes acute infection in humans with characteristic swelling of the parotid gland. While vaccination has greatly reduced the incidence of MuV infection, there have been multiple large outbreaks of mumps virus (MuV) in highly vaccinated populations. The most common vaccine strain, Jeryl Lynn, belongs to genotype A, which is no longer a circulating genotype. We have developed two vaccine candidates that match the circulating genotypes in the United States (genotype G) and China (genotype F). We found that there was a significant decrease in the ability of the Jeryl Lynn vaccine to produce neutralizing antibody responses to non-matched viruses, when compared to either of our vaccine candidates. Our data suggests that an updated vaccine may allow for better immunity against the circulating MuV genotypes G and F.

[Study of mumps immunity after administrating measles-mumps-rubella vaccine among children aged 2-7 years old in Jiangsu Province in 2015]

Objective: To investigate the immunity to mumps after administrating measles-mumps-rubella vaccine (MMR) among children aged 2-7 years old in Jiangsu province in 2015. Methods: A total of 4 190 healthy children aged 2-7 years old, living in local places for at least 3 months, and having been vaccinated at least 1 dose MMR were recruited to the study from Wujin district of Changzhou city, Gaogang district of Taizhou city and Ganyu district of Lianyungang city by using stratified cluster random sampling method between September and November, 2015. Those who did not accept MMR vaccination, who refused venous blood collection, who had affected mumps according to the memory of parents or teachers and who were diagnosed serious disease by clinical doctors were excluded from study. The self-designed questionnaire was used to collect the general information of the subjects and their MMR immunization history; and 0.5-2.0 ml of venous blood was collected from each subject. ELISA was used to detect the mumps antibody level in the serum of patients. Positive was defined as the antibody level ≥108 mU/ml, and negative as <108 mU/ml. χ(2) test was used to compare the difference in positive rates among subjects; and analysis of variance was used to compare the GMC changes in different time points after MMR vaccination. Results: Among 4 190 children, 2 280 were males (54.42%) and 1 910 were females(45.58%), and the positive rate of IgG antibody was 81.38% (3 344). There were 3 156 (95.18%) children vaccinated with one dose MMR, 187 (4.80%) children with two dose MMR, and 1 (0.02%) child with three dose MMR. The difference in positive rate of IgG antibody among different aged subjects showed statistical significance (χ(2)=58.61, P<0.001), the highest positive rate was in group of subjects aged 4-5 years old, at 89.43% (406/454), while the lowest positive rate was found among subjects aged 6-7 years old, at 75.63% (1 648/2 179). The positive rate after one dose of MMR vaccination was 79.14% (3 156/3 988), significantly less than it after two doses (93.03%, 187/201) (χ(2)=22.93, P<0.001). The GMC level at years<1, 1-<2, 2-<3, 3-<4, ≥4 following one dose MMR in the 3 988 children was 152.47, 227.78, 167.08, 126.91, 79.43 mU/ml, whose difference was statistically significant (F=51.29, P<0.001). Conclusion: The sero-prevalence of IgG antibody in the children aged 2-7 years old in Jiangsu province was high. The positive rate among who received two doses MMR was significantly higher than it among who received just one dose, and the GMC level waned with times.

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.

Universal measles-mumps-rubella vaccination to new recruits and the incidence of mumps in the military

In response to the resurgence of mumps, the Korean Armed Forces started the measles-mumps-rubella (MMR) vaccination to all new recruits regardless of prior vaccination history. We evaluated the effectiveness of the vaccination by comparing the incidence between the military and civilian populations before and after implementation of the new policy. The standardized incidence ratio of mumps in the military was 7.06 in the prevaccine period, which declined to 0.96 in the postvaccine period. Vaccine effectiveness was estimated at 86.4%. Incidence rate ratio was lower in the 1996-1998 birth cohort (BC) compared with 1989-1995 BC (0.10 vs. 0.55), suggesting higher effectiveness of vaccination in the 1996-1998 BC. Our data provide evidence for the use of the MMR vaccination in the prevention of mumps in high-risk adults.

Core curriculum illustration: pediatric viral parotitis

This is the 36th installment of a series that will highlight one case per publication issue from the bank of cases available online as part of the American Society of Emergency Radiology (ASER) educational resources. Our goal is to generate more interest in and use of our online materials. To view more cases online, please visit the ASER Core Curriculum and Recommendations for Study online at http://www.aseronline.org/curriculum/toc.htm .

The clinical features and prognosis of mumps-associated hearing loss: a retrospective, multi-institutional investigation in Japan

CONCLUSIONS

The majority of hearing loss due to mumps presents as unilateral profound sensorineural hearing loss, which is refractory to treatment. In rare cases of bilateral total deafness, cochlear implants were beneficial for speech perception. Vaccination against mumps is recommended to prevent mumps-associated hearing loss.

OBJECTIVE

The objective of this study is to investigate the clinical characteristics of hearing loss due to mumps and to evaluate hearing outcomes.

SUBJECTS AND METHODS

The clinical parameters were analyzed under a retrospective multi-institutional study design in patients diagnosed with hearing loss due to mumps at the Otolaryngology departments of 19 hospitals between 1987 and 2016.

RESULTS

Sixty-seven patients with hearing loss due to mumps were enrolled. The study population consisted of 35 males and 32 females, ranging in age from 1 to 54, with a median age of 9.5 years. Sixty-three patients presented with unilateral, and 4 with bilateral hearing loss. Profound hearing loss was observed in 65 ears. Only one ear with severe hearing loss showed complete recovery. Four patients with bilateral hearing loss received cochlear implant surgery. Most of the patients with hearing loss due to mumps had no history of vaccination.

Magnetic Resonance Imaging Findings of Mumps Meningoencephalitis with Bilateral Hippocampal Lesions without Preceding Acute Parotitis: A Case Report

Meningitis is a common central nervous system (CNS) complication of the mumps, a viral infection, but encephalitis and meningoencephalitis are less common in mumps. We describe magnetic resonance imaging findings of acute mumps meningoencephalitis in a 32-year-old male who showed bilateral hippocampal lesions without preceding parotitis. Although it is rare, hippocampal involvement should be considered a CNS complication of mumps infection.

Increasing mumps incidence rates among children and adolescents in the Republic of Korea: age-period-cohort analysis

BACKGROUND

To characterize the temporal dynamics of mumps epidemiology according to the different vaccine strains used, sex-specific trends were decomposed in an age-period-cohort (APC) analysis for mumps cases reported in South Korea.

METHODS

National surveillance data were used to describe the epidemiology of mumps cases from 2001 to 2015. An APC model was used to break down the reported mumps cases into the effects of age, period, and birth cohort.

RESULTS

From 2001 to 2015, the incidence started to increase from fewer than 10 cases to more than 100 cases per 100 000. The incidence rate was highest among males aged 15-17 years during 2013-2015, reaching 508.7 per 100 000 persons. There was an increased incidence during the late teenage years in the 1998-2000 cohort. An age shift towards the earlier teenage years was observed across the 2001-2003 and 2004-2006 cohorts. The risk of mumps increased according to the birth cohort; the net drift from 2001 to 2015 was 27.67 (95% confidence interval 27.5.47-29.90) for males and 27.25 (95% confidence interval 24.91-29.65) for females.

CONCLUSIONS

The increase in mumps seen in Korea may have been affected by the birth cohort exposed to the Rubini strain; however other factors may have contributed to the increase in non-exposed cohorts.

A mumps model with seasonality in China

BACKGROUND

Mumps, an infectious viral disease, classically manifested by inflammation of salivary glands and is best known as a common childhood viral disease with no specific treatment. Although it can be protected by vaccine, there are more than 100,000 reported mumps cases according to the Chinese Center for Disease Control and Prevention. However, the factors and mechanisms behind the persistence and prevalence of mumps have not been well understood.

METHODS

A mumps model with seasonal fluctuation is formulated and investigated. We evaluate the basic reproduction number ℛ0 and analyze the dynamical behavior of the model. We also use the model to simulate the monthly data of mumps cases and carry out some sensitivity analysis of ℛ0 in terms of various model parameters.

RESULTS

It is shown that there exists only disease-free solution which is globally asymptotically stable if ℛ0 < 1, and there exists a positive periodic solution if ℛ0 > 1. ℛ0 is a threshold parameter, and its magnitude determines the extinction or persistence of the disease.

CONCLUSION

Our analysis shows that vaccination rate and invalid vaccination rate play important roles in the spread of mumps. Hence, Our study suggests to increase the vaccine coverage and make two doses of MMR (Measles, mumps and rubella vaccine) vaccine freely available in China.

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.