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Volunteers will become infected with viruses or bacteria under a fresh model

In order to create fresh influenza vaccines, the Department of Biotechnology (DBT) is close to finalizing three initiatives worth about 135 crores, involving Indian and European scientists.

What makes these projects unique is that they include a Controlled Human Infection Model (CHIM): volunteers participating in tests will be infected with infectious viruses or bacteria under specialist guidance. Such studies are being considered in India, which are being used in the growth of vaccines in the United States, the United Kingdom, and Kenya.

A CHIM approach will speed up the process by which scientists can quantify whether potential candidates for the vaccine can be effective in humans and identify factors that determine why some vaccinated individuals become sick and others do not. The risk in such trials is that it is against medical ethics to intentionally infect healthy people with an active virus and make them sick. It also involves endangering human lives.

Ethical Guidelines

By November, vaccine development experts, social scientists and bioethicists are expected to prepare, with the support of the DBT, a guidance document outlining the circumstances under which CHIM studies can be conducted, the profile of potential volunteers, the facilities needed, the informed consent forms they would need to sign and the compensation that can be offered.

There must be approval from the Drug Controller-General of India to post the availability of guidance papers. “Any such trial will have to comply with the rules governing clinical trials in India. The influenza trials will be performed outside India, but what we are hoping to get out of this is learning,” said Gagandeep Kang, Director of India’s Translational Health Science and Technology Institute (THSTI). THSTI scientists are engaged in the development of trial protocols.

Intestinal bugs are not safe too

India would probably create protocols for CHIM to study bacterial or enteric viruses (living in the intestine) such as cholera or typhoid rather than influenza tests, Professor Kang said. If successful, these would generate back-ups to current vaccines for cholera and typhoid. Experience with CHIM may assist to produce vaccine-trained clinical investigators.

Bharat Biotech, a biotech company based in Hyderabad, depended on a CHIM strategy to prove that it’s conjugate typhoid vaccine, while already licensed in India, was efficient in a big population. The potential of the vaccine was assessed by infecting human volunteers with a parasite of typhoid at Oxford University in the United Kingdom with financing from the Bill and Melinda Gates Foundation and the global consortium GAVI.

The findings motivated researchers to test the vaccine among 1 lakh kids in Nepal, Bangladesh, and Malawi. According to Andrew Pollard, UK vaccine test leader and lecturer at Oxford University, the vaccine was over 80 percent protective when tested on the ground. The results will be published in an upcoming issue of the peer-reviewed New England Journal of Medicine.

Traditionally, vaccines are produced from a weakened form of a disease-causing virus or bacteria and injected into the body to coax the immune system into creating antibodies that generate immunity to future infection.  Years of growth of vaccines have shown that vaccines that work in tiny groups of individuals may not always work in big communities, or vaccines that work in one nation may not work in another. CHIM models help vaccine manufacturers decide whether to invest in costly trials or not.


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