Kerala is grappling with a worrying resurgence of measles, with outbreaks reported across several districts and a changing pattern of infection that has prompted public health experts to call for a detailed reassessment of the disease's epidemiology and the state's vaccination strategies.
As of November 6, the Integrated Disease Surveillance Programme had reported 824 confirmed and 1,681 probable measles cases in the state. Five measles-related deaths have been reported, though only one has been confirmed so far. The outbreaks are concentrated in the northern districts of Kozhikode, Malappuram and Palakkad, but cases have been reported more widely, and health authorities are on alert across the state.
What has alarmed experts is not only the number of cases but the changing profile of those affected. Measles was once predominantly a childhood disease, affecting children aged one to five. It is now being reported across age groups, including among fully vaccinated individuals and infants below nine months of age, who are not yet eligible for routine measles vaccination.
The shift suggests that the epidemiology of the disease has changed significantly over the years, and that the strategies designed to control it may need to be rethought.
The last major surge in measles cases in Kerala was in 2022-23. Since then, cases had declined in 2024 and 2025, raising hopes that the disease was being brought under control. The current outbreak has dashed those hopes and exposed gaps in immunisation coverage that have persisted despite decades of routine vaccination.
Measles vaccination was introduced into India's Universal Immunisation Programme in 1985, with a single dose given at nine months of age. A second dose, at 18 months, was introduced in 2010 to address immunity gaps following the first dose and to support the goal of measles elimination.
The two doses of the measles-rubella vaccine, administered between nine and 12 months and between 16 and 24 months, are an effective preventive measure, and health officials have repeatedly stressed that vaccination is available at all government health centres.
Kerala generally reports around 95 per cent coverage for the first dose of the measles-rubella vaccine. Coverage of the second dose, administered at 18 months, has consistently been lower, at around 85 to 88 per cent, with some districts reporting still poorer coverage. Incomplete immunisation remains a major driver of outbreaks, and the gaps are most pronounced in the districts where cases are now concentrated.
Malappuram has emerged as one of the major hotspots, with several localities reporting clusters of infections. Two children died of measles within a week in September, including a 10-month-old infant from Valavannur who died on September 15 and a one-and-a-half-year-old boy who succumbed to the infection subsequently. The district had reported 103 confirmed cases at the time, with infections concentrated in Valavannur, Kuttippuram, Vengara and Pookkottur.
Health department figures indicate that nearly one-third of eligible children in the district had not received both recommended doses during each of the preceding three years.
The Kerala State Commission for Protection of Child Rights has intervened, seeking reports from the district medical officer and the district child protection officer and directing authorities to identify children who may have been left out of the vaccination programme. The intervention underlines the seriousness with which the state is treating the outbreak and the concern that the most vulnerable children are the ones being missed.
Kozhikode has also witnessed a significant increase in infections, with 161 confirmed cases and 116 suspected cases reported by October 2026. Health department officials, at a review meeting in October chaired by Assistant Collector Malavika G Nair, said the disease was spreading mainly among unvaccinated people. One death due to measles was reported in the district.
The district medical officer, L T Saritha Kumari, presented a report at the meeting outlining the spread of the disease and the measures being taken to contain it.
In Kannur, another death was reported recently, that of 15-year-old Dakshith Babu, a student from Thalassery, who died after contracting the disease. The death of a teenager, well beyond the age group traditionally associated with measles, illustrates how the disease's profile is changing. As of October 2026, a total of 538 people had tested positive for measles in the state, with more than 1,000 people developing symptoms.
The disease has claimed four lives, according to reports from early November, before the latest figures were compiled.
The scientific evidence points to a complex picture. A study by the Rajiv Gandhi Centre for Biotechnology, involving 684 children aged four to 18 from Kerala and Tamil Nadu who had received at least two doses of a measles-containing vaccine, assessed their measles antibody levels. Published in JAMA Network Open in August 2025, the study found that 8.5 per cent of the children lacked antibody levels classified as protective.
A related study of 544 mothers found that only 66.8 per cent had adequate measles antibodies to protect their infants.
A World Health Organisation informal technical consultation report, published in the journal Vaccine in May 2025, acknowledged that women acquiring immunity through vaccination rather than natural infection might transfer lower levels of measles antibodies to their babies. This could help explain why infants below nine months, who are not yet eligible for routine vaccination, are now appearing among the cases.
An earlier assessment circulated by the Union Health Ministry's Integrated Disease Surveillance Programme highlighted the growing concern over measles infections among adults, particularly those aged 19 to 35. The changing age distribution of measles infections is not unique to Kerala, and experts say it reflects a broader shift in the epidemiology of the disease as vaccination has changed the pattern of immunity in the population.
Kerala now needs larger epidemiological investigations to establish how many laboratory-confirmed cases occurred among children with two verified vaccine doses, those with partial or no immunisation, and the age break-up of those affected. Such studies would help determine whether the problem is primarily one of missed vaccinations, waning immunity, or a combination of both, and would guide the state's response.
Health Services Director Dr V Meenakshi has said most infections were being reported among children who had not received the vaccine, and the health department has stepped up vigilance in the affected districts. The immediate priority is to identify unvaccinated children and ensure they receive both doses of the vaccine, while also improving surveillance so that cases are detected and isolated quickly.
The outbreak is a reminder that measles, one of the most contagious diseases known to medical science, requires very high levels of population immunity to control. A single infected person can infect up to 18 others in an unvaccinated group, which means that even small gaps in coverage can allow the virus to spread rapidly.
Kerala's experience shows that high average coverage is not enough: the gaps, concentrated in particular districts and communities, are where outbreaks begin.
For the state, the challenge now is twofold. In the short term, it must contain the current outbreak through vaccination drives and surveillance. In the longer term, it must understand why the disease is behaving differently, why fully vaccinated children and infants are being affected, and what that means for a vaccination programme that has been in place for four decades.
The answers will matter not only for Kerala but for the rest of India, where measles elimination remains a national goal.
(Reporting based on The Hindu and Daijiworld.)