New Delhi, Aug. 21: The use of Chinese-made vaccine against Japanese encephalitis (JE) in Indian children without prior safety tests in India amid concerns among scientists has exposed the lack of science-based decision-making in public health, medical experts have said.
The health ministry had immunised nearly nine million children across 11 districts in four states earlier this year, describing it as an “emergency measure” after an outbreak of JE in eastern Uttar Pradesh had killed more than 1,800 children last year.
While its proposed import had already been under debate in medical circles, the 504 adverse reactions, including 22 deaths, in the immunised children have amplified the row. Health officials say the deaths are not connected with the vaccine.
But medical researchers have told The Telegraph that several studies that should ideally have been done before the immunisation are now under way after the campaign. These include studies on the safety of the vaccine, studies on the ability of the vaccine to generate antibodies in Indian children and studies on the live, weakened JE virus contained in the vaccine.
Medical experts said the subject of importing this JE vaccine was never put up for discussion within the National Technical Advisory Group on Immunisation, a body expected to assist in decisions over vaccines for public health.
Health officials have argued that the speed with which the vaccine was delivered has saved children this year. “This campaign has protected thousands of children from JE not just this year, but for many years to come,” said Shobhan Sarkar, a consultant with the health ministry.
“It was the safest, most cost-effective vaccine available to us,” said Sarkar. The Chinese company reduced the price from about Rs 45 a dose to about Rs 8 a dose, he said.
During meetings about the proposed import of the vaccine, researchers had pointed out that the response to a vaccine is often influenced by the nutritional status of the recipient.
It would thus be important to do a “baseline study” on nutritional status and the immunological response to the vaccine in a small subset of the population where it was to be administered.
Some scientists had also pointed out that the introduction of a live, weakened vaccine in areas where wild JE virus already exists should be preceded by studies on “baseline immunity” in the population.
“Only a fraction of people infected with wild JE virus actually get the disease. The majority get infected and acquire immunity to it,” said a virologist.
Scientists had also highlighted the need for evaluating pre-existing immunity against JE in areas where the vaccine was to be given.
But proponents of the vaccine argue these are theoretical concerns because the safety and efficacy of the vaccine has already been proved in more than 200 million children in China, South Korea and Nepal.
“Safety data does not have to be generated from every country,” said Julie Jacobson, director of the JE project with an NGO which provided technical support to the government for the campaign. “Is a check mark (for completed safety tests) more important than the lives of children'”
However, senior virologists point out that the vaccine has not been approved for use in any developed country.
They said the vaccine is made in hamster kidney cells, a material not approved by the WHO for production of vaccines for humans. In the past, experts have described the hamster kidney cells as “not a widely accepted substrate” for production of vaccines.