Effects of a Public Subsidy Program for Mumps Vaccine on Reducing the Disease Burden in Nagoya City, Japan

A review of safety and immunogenicity of a novel measles, mumps, rubella (MMR) vaccine

Measles, mumps, and rubella (MMR) are highly infectious viral diseases affecting young children and have high secondary attack rates. Present MMR vaccines show consistent seroconversion rates for anti-measles and anti-rubella antibodies with variable responses for anti-mumps antibodies. Most common strains for MMR vaccines, currently available in India, are the Edmonston-Zagreb measles strain, Leningrad Zagreb (L-Z) mumps strain, and the RA 27/3 rubella strain. L-Z strain of mumps virus has been found to be associated with aseptic meningitis by different studies from different parts of the world including India. Recently, a novel freeze-dried MMR vaccine developed by Zydus Lifesciences (Zyvac MMR) contains Edmonston Zagreb measles strain, Hoshino mumps strain, and RA 27/3 rubella strain. The Hoshino strain is WHO approved and was found to induce interferon gamma production. This review article aims to provide a comprehensive appraisal of the data available on the safety and immunogenicity of the novel MMR vaccine.

Cost-effectiveness analyses of monovalent mumps vaccination programs for Japanese children

BACKGROUND

The most common preventative measure against mumps is vaccination with mumps vaccine. Over 122 countries have implemented mumps vaccine routine immunization programs, mostly via Measles-Mumps-Rubella (MMR) vaccine. In Japan, the unexpectedly high incidence of aseptic meningitis caused by mumps vaccine led to the discontinuation of the MMR national vaccination program in 1993, inadvertently resulting in the re-emergence of mumps. Plans of introducing monovalent mumps vaccine into routine vaccination schedule have become one of the emerging topics in health policy that has warranted the need in evaluating its value for money.

METHODS

We conducted cost-effectiveness analyses with Markov model and calculated incremental cost-effectiveness ratios (ICERs) of two different vaccination programs (a single-dose program at one-year-old, a two-dose program with second dose uptakes at five) compared to status quo from both payers' and societal perspectives. Transition probabilities and utility weights in estimating quality-adjusted life-year (QALY), and disease treatment costs were either estimated or obtained from literature. Costs per vaccination were assumed at ¥6140 (US$58;1US$ = ¥106).

RESULTS

Both programs reduce disease treatment costs compared to status quo, while the reduction cannot offset vaccination cost. ICER of either program is found to be under ¥5,000,000 (US$47,170)/QALY willingness-to-pay (WTP) threshold from either perspective. Results of probabilistic sensitivity analyses expressed by net monetary benefit indicated that at the WTP threshold, the acceptability is at 92.6% for two-dose vaccination program, 0% for single-dose vaccination program, and 7.4% for current no vaccination program. Two-dose program was optimal among the alternatives. One-way sensitivity analyses revealed that proportion of mumps-related hearing loss among mumps cases and vaccine effectiveness (VE) were key variables in changing the ICERs.

CONCLUSION

Routine vaccination program of single- and two-dose programs were cost-effective from both payers' and societal perspectives. Between the two, the two-dose vaccination program was observed to be more favorable.

Factors associated between behavior of administrating or recommending mumps vaccine and primary care physicians' knowledge about vaccination: A nationwide cross-sectional study in Japan

BACKGROUND

In Japan, the mumps-containing vaccine was withdrawn from routine vaccination in 1993, and it became a voluntary vaccination. This study aimed to evaluate the association between the physicians' knowledge about vaccinations and the administration or recommendation of the mumps vaccine.

METHODS

We conducted a nationwide cross-sectional study targeting primary care physicians (PCPs) in Japan. We used a web-based self-administered questionnaire by Preventive Medicine and Health Promotion Committee Vaccine Team, the Japan Primary Care Association (JPCA), from March to June in 2019. The outcome of the study was the association between PCPs' knowledge about vaccine and the administration or recommendation of mumps vaccine. We obtained the information on background, subsidies of mumps vaccination for children from the local government, and vaccination quiz scores. We performed logistic regression analysis to estimate the odds ratios (ORs) and 95% confidence intervals (CIs).

RESULTS

Among 10,470 PCPs in JPCA, 5075 were excluded. We received responses from 1084 PCPs (20.1%) and enrolled 981 participants in the analysis. PCPs with a higher score on the vaccination quizzes were significantly more likely to administrate the mumps vaccine for adults (adjusted odds ratio [AOR] 1.93, 95% CI 1.45-2.59, p < 0.001) and recommend mumps vaccine to adults than PCPs with a lower score (AOR 1.78, 95% CI 1.33-2.40, p < 0.001).

CONCLUSIONS

We revealed an association between the administration or recommendation of mumps vaccine and PCPs' better vaccination knowledge.

Parents' views on mumps, mumps vaccine, and the factors associated with vaccination in Japan

BACKGROUND

The measles-mumps-rubella vaccine was withdrawn from the National Immunization Program in 1993 because aseptic meningitis was reported as a post-vaccination adverse reaction in Japan. This study aimed to measure the uptake of and determinants influencing mumps vaccination, including concerns about adverse reactions.

METHODS

We conducted this cross-sectional survey for all parents whose children underwent 18-month health checkups in Kanazawa City between October 2019 and February 2020. Community nurses interviewed the parents using a unified questionnaire, and 1422 parents responded.

RESULTS

Based on records from maternal and child health handbooks, the mumps vaccination rate was 55.6%. The most common reason for parents not vaccinating their children against mumps was that "it is not a routine vaccine" (35.9%), whereas "concern about adverse reactions" accounted for only 2.2%. In multivariate analysis, the significantly positive factors associated with vaccination against mumps were children whose parents knew that adverse reactions were fever, rash, diarrhea, and vomiting; had received a recommendation for vaccination from their family members; had read the Vaccination Guide issued by the city; vaccinated with other voluntary vaccines or treated for gastroenteritis; and had a deep general understanding of vaccination. Conversely, the significantly negative factor was children whose parents had not received any recommendation for vaccination.

CONCLUSION

The mumps vaccination rate could be improved by adding the mumps vaccine in the routine vaccination program and educating parents by disseminating correct information on mumps and the mumps vaccine, and by primary care physicians routinely recommending vaccination.

Impact of local vaccine subsidization programs on the prevention of mumps in Japan

In Japan, although a mumps vaccination is outside the national universal vaccination program, some local governments have implemented their own program. However, little is known regarding the implementation status and the impact of these programs. In this study, we investigated the impact on the prevention of mumps, after identification of the status of the local government subsidization programs. We identified the implementation status of the subsidization programs using the websites of local governments. We retrieved the number of reported mumps cases from designated sentinel sites through the Surveillance of Infectious Diseases System implemented according to the Infectious Disease Control Law. Using this data, the impact of the subsidization program on prevention of mumps was assessed by comparing the number of mumps cases per site during the 2015-2016 outbreak among the areas categorized by the subsidization status, using a Poisson regression model. As of 2019, 26.2% (456/1,739) of the local governments were considered as having subsidization programs. We retrieved 52,719 mumps cases from 2010 to 2019. The number of mumps cases per sentinel site tended to be low in areas implementing a subsidization program, compared with the no-implementation areas throughout the data collection period. The adjusted model confirmed that the subsidization program implemented between 2010 and 2015 impacted on the number of mumps cases during the 2015-2016 outbreak, with a decrease in the numbers. Further studies with detailed data including vaccination coverage should be conducted.

Close the gap for routine mumps vaccination in Japan

Mumps is a vaccine-preventable disease. Because the mumps vaccine can cause aseptic meningitis in rare cases, this vaccine is not routine in Japan. This has led to low vaccine coverage and severe disease burden in Japan. The present review summarizes mumps epidemiology and vaccination and discusses effective future strategies to mitigate the current disease burden of mumps in Japan. Although a recent study reported that mumps vaccine coverage rates are improving in Japan, current coverage rates are far below the optimal rate to suppress the ongoing epidemic, which has caused an average annual financial loss of 85 billion JPY between 2000 and 2016. Recent reports have demonstrated a much lower incidence of vaccine-induced aseptic meningitis in newly developed vaccines, especially when administered at 1 year of age. Cost-effectiveness studies suggest that routinization of the currently distributed domestic vaccine would be highly cost-effective. In addition, questionnaire surveillance data suggest that the majority of the Japanese population accepts the nominal risk of the vaccine when the proper information is provided. Finally, there are some successful programs in Japan that have attained high vaccine coverage rates with financial support from local governments. Taken together, these data suggest that the mumps vaccine should be immediately included in routine vaccines in Japan.

The estimated impact of decreased childhood vaccination due to COVID-19 using a dynamic transmission model of mumps in Japan

The exact impact of the decline in childhood vaccination coverage during COVID-19 outbreak has not been estimated for any vaccine-preventable diseases. Our objective was to evaluate the impact of decreased mumps vaccination due to COVID-19 on the disease burden of mumps in Japan. Using a previously validated dynamic transmission model of mumps infection in Japan, the incidence rate of mumps over the next 30 y since July 2020 was estimated. The estimated average incidences were 269.1, 302.0, and 455.4/100,000 person-years in rapid recovery, slow recovery, and permanent decline scenarios. Compared with the rapid recovery scenario, the incremental number of mumps cases, total costs, and QALYs loss over the next 30 y were 6.53 million cases, 2.63 billion USD, and 49,246 for the permanent decline scenario, respectively. In conclusion, the persistent decline of mumps vaccination rate as an impact of COVID-19 causes a significant incremental disease burden of mumps, which is consistent irrespective of the possible decline of transmission rate of mumps infection, unless the rapid recovery of coverage rate is achieved. The immediate measures to advocate the vaccination program is essential to mitigate the incremental disease burden in the COVID-19 period.

Cases of aseptic meningitis after vaccination against mumps in Russia (2009-2019)

OBJECTIVES

Mumps is a highly contagious viral infection prevented by immunization with live attenuated vaccines. Mumps vaccines have proven to be safe and effective; however, rare cases of aseptic meningitis (AM) can occur after vaccination. The range of meningitis occurrence varies by different factors (strain, vaccine producer, and so on). Monovaccines or divaccines (mumps-measles vaccine), prepared from the strain Leningrad-3 (L-3), are used in Russia. Meningitis occurrence after vaccination has been established previously as very low. Nevertheless, with the number of children being vaccinated every year, vaccine-associated AM cases still occur. There is no official statistics on AM incidence after mumps vaccines, and information on AM features as an adverse event of mumps vaccination is limited and mostly devoted to vaccines, prepared from strains other than L-3.

STUDY DESIGN

The study included patients with AM who were vaccinated against mumps in the previous 30 days before the present disease onset during 2009-2019.

METHODS

Patients admitted to Infectious Clinical Hospital No. 1, Moscow, Russia, with AM were observed by a pediatrician and were screened for etiological agents of meningitis.

RESULTS

Seven patients were enrolled, and clinical features and the course of infection are presented.

CONCLUSIONS

Detection of only 7 cases of AM associated with mumps vaccination during the 10-year period supports very low occurrence of this adverse event after immunization with the L-3 strain-based mumps vaccines. Nevertheless, the annual number of AM cases that occur after mumps vaccination remains unknown and poorly diagnosed in practice because of the low awareness of physicians of this adverse reaction. Detection and objective coverage of such cases can lead to a weakening of 'antivaccination' moods in a society and to restoration of confidence in the healthcare system.