No need for booster dose of Covishield: WHO
Premium- WHO said that the need and timing of booster doses will be evaluated as further data accumulate
NEW DELHI: World Health Organisation (WHO) indicated that there is “no need" for a booster shot, amidst rising concern for a booster dose of covid-19 vaccines after six months of complete vaccination among elderly and healthcare workers in India.
“There is, currently, no evidence indicating a need for further doses once an individual has received two doses," stated the interim recommendations by WHO for use of ChAdOx1-S (recombinant) vaccine known as Covishield in India manufactured by Serum Institute of India (SII).
The interim guidance has been developed on the basis of the advice issued by the Strategic Advisory Group of Experts (SAGE) on immunization on 8 February 2021 and was updated on 21 April 2021 and 30 July 2021. The need and timing of booster doses will be evaluated as further data accumulate, WHO further said.
With over 10% of the eligible population in India fully vaccinated, as per the data from Co-WIN system, a debate is abuzz among this group about the potential need for a booster shot. This is when close to 27% of the 940 million eligible population has had only one dose and several awaiting.
The countrywide covid-19 vaccination drive was rolled out on 16 January 2021 in India with Covaxin and Covishield. Majority of doses provided so far in India are of the SII manufactured Covishield.
The central government indicated that it is not considering booster doses of covid-19. “The covid-19 vaccines have been developed very recently, therefore, scientific evidence is still evolving globally regarding the duration of protection," Bharat Pawar, minister of state health and family welfare informed the parliament last week.
To be sure, individuals have taken booster doses in certain states, flouting current covid-19 vaccination guidelines. The central government asked states to ensure that the “irresponsible" practice of wasting “scarce commodity" is immediately stopped.
After vaccination, visible immunity is developed in the form of antibodies that can be measured, along with invisible immunity known as T-Cells, which possess memory power and alerts the body. Thus, having antibodies is not the only sign of our body’s immunity power.
Factors like T-Cells cannot be measured. It has to be seen as to how long after vaccination people can be saved from serious illness and mortality. But, for now, all vaccinated individuals will remain safe for six months to a year, said Dr N K Arora, chairman, India's covid-19 working group of the National Technical Advisory Group on Immunisation (NTAGI).
WHO had earlier said that currently, it does know whether booster vaccines will be needed to maintain protection but the question is under consideration by researchers. Clinical trials on these vaccines only began a year ago, and roll-out across populations even more recently, therefore, limited data is available.
There are various views on booster covid vaccine doses across the world. Center for Disease Control advisory group is considering whether fully vaccinated Americans with weakened immune systems need a booster shot. In parallel, European Medicines Agency recently said it was too early to determine whether more than the two shots of the vaccines will be required, adding it was confident that the established regimen was sufficient.
India’s Bharat Biotech is conducting trials on the third dose for Covaxin. US pharma giant Pfizer has said it is seeking emergency authorisation for a booster shot for its two-dose mRNA covid-19 vaccine as immunity conferred after taking it may wane over time.
According to University College London (UCL) researchers, antibody levels start declining from as early as six weeks after complete vaccination with Pfizer and AstraZeneca jabs and can reduce by more than half over 10 weeks, highlighting the need for booster doses.
The UK government, last week, said it is preparing to deliver booster covid-19 vaccine shots from September, in case extra protection is needed to deal with waning immunity from initial doses and to bolster protection against new variants of the SARS CoV2.
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