Booster Effect Even At 6 Months, Don't Worry: Experts On Cov
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Four to six weeks, six to eight or eight to 12? The increasing gap between two Covishield doses in India while the UK reduces its window has laypersons confused, but several experts say there is little reason to worry and second jabs anytime before six months can still be effective boosters.

The government last week extended the gap between two doses of the Covishield COVID-19 vaccine to 12-16 weeks, up from the previous maximum of eight weeks, on the recommendation of the National Technical Advisory Group on Immunisation (NTAGI). A day later, UK cut the gap from 12 weeks to eight weeks in view of the spread of the B.1.617 variant that originated in India.

Responding to concerns that India increased the gap primarily because vaccines were in short supply and many states had complained of acute shortage in supplies, immunologist Rath said vaccine dosing is quite flexible and forgiving. Once four weeks have passed, the next dose can be taken whenever practicable, until six months.

According to the scientist, vaccine doses will be safe no matter when they are taken but will not provide any great "boosting" if given within less than a month or so of the previous dose. So vaccine doses can be taken any time after at least four weeks have passed from either the first dose or after an actual episode of COVID-19, Rath, from New Delhi's National Institute of Immunology (NII), told.

Secondly, vaccine doses will give perfectly good boosting if given any time up to as much as six months or so after a previous dose. Referring to the UK reducing its Covishield doses gap just as India increased its, immunologist Vineeta Bal said these decisions are taken based on ground realities and there is no yes or no answer to whether they will have any consequence on tackling the variant better

A vaccine triggered immune response, will start declining with time. However, at the end of 12-16 weeks it is unlikely to come to complete baseline level. Hence a booster effect can still be obtained after a gap of 12-16 weeks, Bal said. There are also data from various clinical trials for Covishield which are suggestive that a booster after 12-16 weeks will be fine, she added.

According to a peer-reviewed study published in The Lancet in February, the coronavirus vaccine developed by AstraZeneca and Oxford University is more effective when its second dose is given around three months after the first, instead of six weeks later. The NTAGI has also stated that those having laboratory test proven SARS-CoV-2 illness should defer COVID-19 vaccination for six months after recovery.

According to the Health Ministry's current protocol, the vaccine is to be taken four to eight weeks after recovery from COVID-19. Rath said the basis for this step seems to be based on the fact that there are good antibody levels in most people who have had COVID-19 and that they last for at least six months.

RT-PCR positive patients post-recovery do not remain as vulnerable as those who are neither vaccinated nor infected. They have enough immunity in them, generally. Just because of this recommendation, the situation is not likely to worsen in India. Other things like unavailability of vaccine for a large section of people is more of a problem, Bal added.

Dr. T●●●●z H●●●●●●i and 3 others like this5 shares
A●●●●y j●●n
a●●●●y j●●n General Medicine
But the government has issued a guidelines in which a person contacted with covid 19 should wait for atleast 3 months to get vaccinated. People who got infected can also get infected again in these 3 months , so what can be done for that?
May 21, 2021Like
L●●●●●y R●j
L●●●●●y R●j General Medicine
Data is not available after 12weeks in any peer to peer or by any international journal/community what if 2nd dose not act like as is should be after 1st dose??? When study data shows only effective in only 8-12weeks! 12weeks is upper limit beyond that no study conducted yet or no data available to show effectiveness. Yes we know other routine vaccine helps by extension in time but everything failed so far to treat a COVID-19 patients we need to be keep learning at this point studies should be considered before taking action... Read more
May 21, 2021Like