Several countries are looking for options for separate covid vaccines for second doses or booster shots amidst various issues like supply delays, safety concerns of vaccines that have hindered inoculation campaigns. But Health professionals think it is quick to say if vaccine booster shots will be required.
There is not adequate evidence to either confirm or reject the necessity for a booster dose after Covid vaccination, said World Health Organisation's chief scientist Soumya Swaminathan.“We do not have the information that’s necessary to make the recommendation on whether or not a booster will be needed,” she said.
"Science is still evolving,” the WHO chief scientist added.
Calling the buzz to be " premature", Swaminathan said that even the high-risk persons across the world have not yet taken the first course of vaccination.
What are booster shots?
Presently, the vaccines given against the Covid virus include two doses. Since it is said that the effect of vaccination may not remain for long, many nations are thinking of an annual or booster shot.
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Covid booster shots will soon be rolled in the UK to avert another surge.
Health Secretary Matt Hancock said last month that seven different vaccines are being tested on participants in England. It will be the world's first vaccine booster study.
Those in the UAE who had got inoculated with a vaccine produced by China National Pharmaceutical Group (Sinopharm) are being given Pfizer as a booster shot. On June 4, Bahrain said that eligible candidates can get a Pfizer booster shot or the Sinopharm vaccine regardless of whichever shot that had been given initially.
The US National Health (NIH) said that on June 1, a clinical trial on fully vaccinated individuals has begun to examine the safety and immunogenicity of a booster shot of a different vaccine.
Mixing different vaccines reasonable?
"It seems to be working well, this concept of heterologous prime-boost opens up the opportunity for countries that have vaccinated people with one vaccine and now are waiting for the second dose they have run out of, to potentially be able to use a different platform vaccine,” said Soumya Swaminathan on combining two vaccines amid its scarcity.
However, she added that early data from the UK, Spain and Germany, where the two different types of vaccines "mix-and-match" regime were used had shown complaints of more pain, fever and other minor reactions in comparison with two doses of the same inoculation.
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“Still, the so-called heterologous prime-boost combinations appear to spur a more robust immune response, leading to both higher levels of virus-blocking antibodies and the white blood cells that kill virus-infected cells,” Soumya Swaminathan added.