The story so far: Mumps, an acute viral infection which historically affects children, has been spreading like wildfire in Kerala, for the past few months. Not just Kerala, a resurgence in cases was being reported from several States, including Maharashtra, Telangana and Andhra Pradesh as well. Cases which began appearing sporadically around November 2023 in the Malappuram and Kozhikode districts of Kerala, have since then spread to Palakkad and Thrissur too, resulting in major community outbreaks. The case tally this year alone has reached 15,637, as on March 22, with 6,675 cases being reported this month alone. Such an uncontrolled surge in cases could lead to an increase in the number of complications of mumps, like meningoencephalitis or pancreatitis, public health experts fear.
Is it a cause for concern?
Mumps is a self-limiting, airborne viral disease and 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. There is no specific treatment and the patient recovers with rest and symptomatic management in about two weeks. With only half of the infected children developing the classical disease and close to 30% remaining asymptomatic, cases mostly go unreported, indicating that the reported cases are a gross underestimation of the actual cases in the community.
From the view point of public health, measles, which can cause significant morbidity and mortality, has always been considered a priority, rather than mumps. However, with cases being reported in epidemic proportions, several cases arising from the complications of mumps like encephalitis, epilepsy, aseptic meningitis and acute pancreatitis, have been reported at Kozhikode Medical College hospital. The other significant complication brought forth by mumps is the virus’s effect on the gonads (reproductive glands) in both males and females. In males, it presents the rare yet distinct possibility of infertility or a drop in sperm count in the long term.
Why is the mumps vaccine not part of the national immunisation schedule?
Despite being a vaccine-preventable disease, mumps has never been a part of the Universal Immunisation Programme (UIP) because of the disease’s no-mortality profile and the perception that it has low public health significance. However, the Indian Academy of Paediatrics (IAP) has always maintained that the public health significance of mumps has been underestimated mainly because of the poor documentation of clinical cases, its complications and patients’ follow-up data as well as the lack of published studies. There is no nationally representative data on incidence of the disease. There is very little information on the actual long-term morbidity profile of the disease, even though the disease is known to have some impact on reproductive organs.
How can the current outbreaks be controlled?
Health officials maintain that creating public awareness about the disease and the importance of isolation is the most important tool in bringing down the transmission of the disease. Mumps is primarily being reported in un-immunised children and adolescents and hence improving general immunisation cover is important. Transmission of the disease begins before the symptoms actually manifest and isolation of the patient for a full three weeks is necessary to limit the spread of the disease.
Health officials reckon that one of the reasons for the large number of school-based outbreaks in Kerala is because children were allowed back to school as soon as there was symptomatic relief, before the three weeks isolation period was up. They hope that there will be a break in transmission and a drop in new cases once schools close for the summer break.
What should be the strategy ahead?
According to the World Health Organization (WHO), vaccination strategies targeting mumps control should be closely integrated with existing measles elimination and rubella control.
The IAP for one, has always advocated the use of MMR (Mumps-Measles-Rubella) vaccine in UIP, which has been available in the private sector for a long time. There are no studies from India on the effectiveness of the mumps vaccine. But globally, the protection from two doses is estimated to be between 70-95%, if the coverage is high.
In 2014, Kerala, as part of its own initiative to protect children from Rubella, had replaced the second dose of measles vaccination given at 18 months to infants in UIP, with MMR. However, in 2017, when the Centre introduced Rubella vaccine in the UIP, replacing the two doses of measles given at nine months and 15 months with the MR vaccine (Measles-Rubella), Kerala also followed suit. Kerala has now written to the Centre on the mumps resurgence happening in the State and the need to replace MR vaccine in the UIP with MMR vaccine.
