Kerala has been experiencing explosive outbreaks of Hepatitis A, with increased mortality and morbidity, over the last four years
Clinicians and public health experts in the State have now issued a warning that Hep A is no longer a simple disease in the State because of the age shift in the susceptible population, from children to young adults.
Doctors are reporting severe and atypical symptoms in those affected, including a prolonged phase of high liver enzyme levels, extra-hepatic complications such as bone marrow suppression and many young adults going into fulminant hepatitis requiring liver transplantation.
If the government cannot ensure safe drinking water for the people, then the least it can do is protect people through universal Hep A vaccination, they point out.
What’s happening
Last year, (as on December 30), Kerala had reported a total of 31,536 confirmed and probable cases of Hep A and 82 deaths. In 2024, the State had reported 28,412 cases and 96 deaths.
The situation is no better this year, with 12,437 (confirmed and probable) cases and 125 deaths, of which 69 are confirmed Hep A deaths.
“The Malappuram-Kozhikode belt continues to be the hub of water-borne infectious diseases, especially Hep A and Shigellosis, in the State. Clinicians have been seeing severe Hep A with dysregulated or inflammatory response, requiring treatment with steroids.This cytokine storm is something we have been seeing in many infectious diseases now, especially post-Covid,” says R. Aravind, head of infectious diseases, Thiruvananthapuram Government Medical College.
What’s changing
Across India, Hep A has traditionally been a universal childhood disease, which is mild and self-resolving, leaving those affected with life-long immunity against the disease. But in Kerala, better socio economic status and improved sanitation meant that children grew up without exposure to Hep A, becoming immunologically naive adults, vulnerable to all complications of adult hepatitis
The epidemiological shift in the age group of Hep A patients is very evident, with 90% of the patients in the 18-40 years age group, for whom eating out, especially from wayside shops and so-called exotic juice shops, is a way of life, says V.K. Shameer, assistant professor of general medicine, Kozhikode Government Medical College.
“Over the last two years, the Hep A case load has been huge and we see a lot of complications. In about 1% of the cases, patients went into acute liver failure and death, and some others ended up requiring a liver transplant,” Dr. Shameer says.
Many patients who went into acute liver failure were saved using the plasmapheresis procedure, which has been incorporated into the State’s Hep A management protocols since the last two years.
“We also had a youngster who developed the rare complication of bone marrow suppression following Hep A, which progressed to hepatitis-associated aplastic anaemia, requiring a bone marrow transplant,” he notes. In several others who apparently recovered, the bilirubin levels remained high for three to six months, also known as relapsing or cholestatic hepatitis. “Some of these are adult Hep A complications documented in literature. But it is only in the last two years that we are seeing these manifestations,” Dr. Shameer says.
What the research says
The clinical observations of atypical and severe symptoms in adults with Hep A is corroborated by two recent studies from Kerala
A multi-centre study done across six tertiary care hospitals in Kerala in 2024-25, ‘Clinicopathological Profile and Outcomes of Severe Hepatitis A Outbreak in India: A Multicenter Cross-sectional Study’, which studied 324 adults (mean age 32 years) with confirmed Hep A, reported that Kerala was witnessing a paradigm shift in Hep A — from a benign childhood illness to a multisystem disease in adults characterised by immune dysregulation, extra-hepatic organ involvement and higher mortality. The study was published in the Journal of Clinical and Experimental Hepatology this year.
The researchers reported atypical features such as pulmonary complications (16.8%), acute kidney injury (13.4%), hemophagocytic lymphohistiocytosis (HLH) in 12.8%. Therapeutic interventions included high steroid use (30%), plasmapheresis (21%), continuous renal replacement therapy (7.8%) and mechanical ventilation (10%)
In yet another study published in April 2026 in BMC Infectious Diseases, based on Kerala surveillance data, researchers examined more than 34,000 confirmed and probable HAV cases between 2020 and 2024, alongside detailed immune profiling of infected patients.
The study reported that adults infected later in life had 8.4 times higher odds of moderate-to-severe disease. The immunological profile done in Hep A patients showed that adults have a larger reservoir of CD 8 and primed memory T cells, which mount a higher inflammatory cytokine response, resulting in 18% of adults getting hospitalised against zero hospitalisation in those less than 18 years.
This study thus shuns the theory about increased HAV virulence and points to immune dysregulation in adults as the reason why they suffered extensive liver damage following Hep A.
Why vaccination is needed
This also adds weight to the argument for universal Hep A vaccination in Kerala because there is a plausible biological reason why exposure to HAV in adulthood can be dangerous.
“It is indeed a shame that on one side we are extolling the State’s public health successes and on the other side we are unable to provide safe drinking water to the public. Improving water safety cannot be achieved overnight whereas there are studies proving the cost effectiveness of universal Hep A vaccination in Kerala. This is important because the economic fallout of huge Hep A outbreaks — apart from high morbidity and loss of lives — is immense,” a senior public health expert says.
Previous studies done in Kerala have reported that the average out-of-pocket expenditure incurred by a family, when one adult member is infected by Hep A is nearly ₹25,000.
Published – August 10, 2026 01:05 pm IST