A resurgence in mumps outbreaks across several States in India from 2023 onwards, has brought forth this question: is the disease now an emerging public health problem that is significant enough to warrant prevention through immunisation? Public health experts are debating this issue.
In Kerala for instance, cases of mumps have spiked phenomenally, especially in recent months. From an average of 2,500 cases annually, cases surged to 74,907 in 2024. The trend seems to be continuing, with 16,504 cases already reported this year as of March 25, and of these, over 4,000 cases have been reported this month alone.
Public health experts say that as the cohort of susceptible individuals dwindle due to natural immunity acquired through contracting the infection, the outbreaks will peter out over the next few months. However, as the number of cases go up in the community, the number of cases with mumps-related complications are also likely to go up.
This, and the fact that over 85 schools and several tribal hostels had to be closed for varying durations in 2024, has prompted Kerala to explore the possibility of introducing the mumps vaccine as part of the immunisation schedule.
Understanding mumps
Mumps is a self-limiting, airborne, viral disease which presents as fever and headache in mostly children and adolescents, with painful swelling of the salivary glands (parotid glands) on both sides of the face. The patient usually recovers with rest and symptomatic management in about two weeks.
Even though mumps is a vaccine-preventable disease, because of its low mortality profile, the mumps vaccine has never been a part of the nation’s Universal Immunisation Programme. From a public health perspective, measles, a more infectious and severe disease, has always been considered a priority for elimination.
There is no nationally representative data on the incidence of the disease, and very little information on the actual long-term morbidity profile of mumps, even though the disease is known to have some impact on reproductive organs, doctors say.
“Mumps may not be as harmless as it is made out to be, especially if it is occurring in epidemic proportions in a previously unvaccinated community. Though we do not have exact figures, there were reports of hospitalisations following known complications like aseptic meningitis, encephalitis and acute pancreatitis from medical college hospitals in Kerala. The point is, when mumps is a vaccine-preventable disease, should we allow the disease a run through the community?”, asks I. Riaz, State president of the Kerala chapter of the Indian Academy of Paediatrics.
In a research paper, ‘Is it Right Time to Introduce Mumps Vaccine in India’s Universal Immunization Program?’, which appeared in the 2016 issue of Indian Paediatrics, authors S.R. Vaidya and V.S. Hamde say that mumps is indeed a significant public health problem in India, but that it does not garner attention due to the absence of a surveillance and documentation system.
While the public health significance of mumps-related morbidities is not well documented, paediatricians say that the virus is known to affect the gonads (reproductive hormone glands), causing orchitis (inflammation of the testicles) in males and oophoritis (inflammation of the ovaries) in females. Serious and long-term complications like infertility are considered to be rare, but neither can it be said with certainty that the virus does not cause testicular damage, which could lead to a drop in sperm count in the long run.
In the article ‘Mumps Orchitis: Clinical Aspects and Mechanisms’ by Wu et al., which appeared in Frontiers in Immunology (2021), researchers point out that orchitis is a common complication of mumps and that it occurs in as high as 40% of all mumps cases in young adult men
What is mumps?
Mumps is an acute disease of children and young adults. Humans are the only known host for mumps virus, which is spread via direct contact or by airborne droplets from the upper respiratory tract of infected individuals.
Mumps if frequently reported in children aged 5-9 years of age, although both adolescents and adults may be affected. After an incubation period of some 2 to 4 weeks mumps begins with non-specific symptoms such as myalgia, headache, malaise and low-grade fever. Within days, these symptoms are followed by unilateral or bilateral swelling of the parotid salivary glands, with other salivary glands affected in 10% of cases.
Normally mumps is a mild, self-limiting disease and disappears without sequelae. However, complications may occur such as encephalitis or sensorineural deafness. Orchitis (a painful inflammation of the testes) occurs in 20% of young adult males who develop mumps.
Source: WHO
The MMR vaccine
At present, India’s Universal Immunisation Programme (UIP provides the MR vaccine, which protects against measles and rubella. Under the UIP, the MR vaccine is administered to infants at 9 months and at 18-24 months. A vaccine for mumps has been available for over 50 years however, and, in several countries, as well as in private hospitals in India, it is provided in combination with the MR vaccine, as the Mumps-Measles-Rubella (MMR) vaccine.
Following a recent meeting of Kerala’s State Technical Advisory Group on Immunisation (STAGI), the Additional Chief Secretary (Health) as well as the Director of Health Services had written separate letters to the Union Health Ministry asking for the inclusion of the mumps vaccine in the UIP schedule, through the MMR vaccine, to prevent future mumps outbreaks, Health Department officials said.
And its not just Kerala, several States that have been experiencing huge mumps outbreaks since last year have also made similar requests to the Centre, that MMR vaccine be introduced in place of the MR vaccine in the UIP schedule. In December, Tamil Nadu’s Health Department also wrote to the Union Health Ministry in this regard: the State records at least 150 cases of mumps per month now.
“However, introducing a new vaccine in the community is a long process as innumerable factors — vaccine availability, price, supply and most importantly, the possible side effects of the vaccine — will have to be studied ahead. This issue is something the National Technical Advisory Group on Immunization (NTAGI)
will take up soon, we hope,” a senior Kerala Health official said.
At present, the use of the MMR vaccine is advocated by the IAP and it is included in the IAP’s immunisation schedule. Most private hospitals follow the IAP’s vaccination schedule.
The World Health Organization’s official position has been that reaching all children with two doses of the measles vaccine, either alone, or in a measles-rubella (MR), measles-mumps-rubella (MMR), or measles-mumps-rubella-varicella (MMRV) combination, should be the standard for all national immunisation programmes.
While there are no studies from India on the effectiveness of the mumps vaccine, globally, the protection from two doses is estimated to be between 70-95%, if the vaccination coverage is high.
What does Kerala plan to do?
In 2014, Kerala had, on its own, replaced the second dose of the measles vaccination in the UIP with the MMR (mumps-measles-rubella) vaccine, as part of a State-level initiative against rubella. But in 2017, when the Union Health Ministry sought to replace the single measles vaccine given at 9 months and 18-24 months with the MR vaccine, Kerala discontinued the MMR vaccine it was giving and adopted the MR vaccine for routine immunisations.
In Kerala, most of the mumps cases are seen now in the 5-9 year age group, and hence at least three doses of the vaccine may be needed for full protection, Dr. Riaz said. The IAP advocates a three-dose schedule, at nine months, 18 months and a booster dose at five years. The Centers for Disease Control and Prevention, U.S. and the WHO recommend a two-dose schedule.
Kerala’s STAGI’s recommendation was that, for the time being, the State retain the MR vaccine at nine months, while the MR dose at 18-24 months is replaced by MMR. This should be followed by a booster dose of MMR at five years.
“This involves an estimated additional expenditure of ₹15 crores annually and we are exploring the possibility of whether local self-government bodies can find the funds for this or if we should restrict the provision of the free MMR vaccine to just the BPL (below poverty line) category. For Kerala too, this is a big decision to take on its own because these funds will have to be committed so that there is no disruption in vaccine supply,” a senior Health official said.
The path forward
Researchers point out that there was a surge in the global incidence of mumps in 2017-19 and that there are concerns about the disease shifting from children to young adults. There is not much documentation however, on whether mumps contracted in childhood might contribute to infertility or testicular damage later in life.
At present, mumps is primarily being reported in un-immunised children and adolescents and hence, improving general immunisation cover is important, say doctors. Isolating patients for three weeks and using face masks can prevent the spread of the disease in the community. Identifying the source of infection may not be easy because the spread occurs before the onset of symptoms . In about 30% of cases, individuals remain asymptomatic.
Most importantly, a public awareness campaign on mumps is in order so that people learn to recognise the disease and understand the importance of isolation to prevent community transmission.
Published – March 30, 2025 01:47 pm IST
