Covaxin Offers Protection Against Multiple Variants: Study

CHANDIGARH: Unlike other existing vaccines against Covid, it has been found that Bharat Biotech’s Covaxin targets not just mutations in spike proteins but also multiple proteins, thereby offering protection against alpha, beta, gamma, kappa and delta variants. Also, the protection offered by the indigenous vaccine is generated through memory cells (T cell, B cell), which is long-term and is not affected by waning of antibodies. This has been concluded by a group of scientists in the first ever preprint study led by the National Institute of Immunology (NII), Delhi.
Based on data generated by the study, scientists have proposed further investigation for a booster dose via intranasal route to control the infection and virus transmission.

“We studied in a cohort for six months where Covaxin induced good memory response. So we are confident that till six months of full immunisation, no booster dose is required. A follow up of this cohort thereafter, will help us to understand if we really need booster shots or not,” said Dr Nimesh Gupta, corresponding author of the study at NII. “The best protection was found against alpha then delta and the least was against beta variants,” he added.

The immune response induced by the vaccine was found to be similar to the natural infection. “We have the whole virus and our immune system mounts the responses to all the proteins of the virus. The impact of this vaccine may be similar to the natural infection where it allows our immune system to mount the memory responses against multiple proteins. The benefit is that if a huge variant comes from a mutation in the spike protein, which may escape the vaccine only targeting spike proteins, in this vaccine there are some supplementary protective responses from responses against other proteins,” said Dr Gupta.

Also, the vaccine, in low doses, can be tested on the paediatric population. “We do not need a high quantity of immune responses for Covid but they should be optimum. In children, low doses can be protective,” said the scientist.

Researchers believe that the memory generation is mainly due to the adjuvant in the vaccine which has been used for the first time. “Whole virus has a response against multiple proteins so that you can be completely protected against variants. And this adjuvant is generating immune responses–which is very close to the nature of natural infections,” said Dr Gupta.

The study was conducted in collaboration with AIIMS New Delhi, Maulana Azad Medical College and Lok Nayak hospital, Delhi, Center for Infectious Disease and Vaccine Research, La Jolla Institute for Immunology, California, Division of Infectious Diseases and Global Public Health, University of California, San Diego, Translational Health Science and Technology Institute, Faridabad and ESIC Medical College and Hospital, Faridabad.

Source: ToI