Should the Covid-19 booster dose be different from the first vaccine?

Agrawal Said In a series of tweets after Covovax became the ninth shot cleared for emergency use by WHO, he said, “It’s better than the third dose AstraZeneca / Covishield as a booster.” However, in the rise of Omicron, he does not believe that “approved versions based on ancestral peplomer proteins are directly very effective against Omicron.”

Citing a study conducted in the United Kingdom, he said, “Immune enhancement after two doses of AZ / Covishield was much better than the inactivated virus vaccine … and because of the variant-specific immune response. Rapid modification of the protein is possible. “

Experts say that boost immunization is jab with only one dose, regardless of the primary dose, even if the initial recommendation for the vaccine is two doses for complete vaccination. Is called. Therefore, if one is completely jabed with two doses of Covishield, the booster will consist of one additional jab, even with another two doses of vaccine.

Experts told the US-based non-profit Mayo Clinic that “all boosters dramatically increase antibody response,” but booster decisions are based on how they responded to the first vaccine they obtained. He said he needed to do it. Young men who were initially vaccinated with the Moderna or Pfizer vaccine may need a J & J booster because the mRNA vaccine is associated with a small risk of heart inflammation called myocarditis. Women under the age of 50 may wish to have a Moderna or Pfizer booster. The J & J vaccine is associated with a slightly higher risk of rare blood clotting in young women, “said Dr. Gregory Poland, Head of the Mayo Clinic Vaccine Research Group.

What’s the idea behind the individual Vax for boosters?

Mixed-and-match doses are a strategy that has been considered for primary vaccination against Covid, the first dose of one vaccine followed by a second dose of another. However, WHO said that the “homologous vaccination” in which the same vaccine is used throughout is given that the primary and booster doses were “mostly evaluated using the same vaccine product throughout the dosing series”. “Currently considered standard practice,” he said.

Listing the reasons for mixing vaccines can range from “lack of availability of the same vaccine product” due to unpredictable supplies to “decreased responsiveness, increased immunogenicity, and increased vaccine efficacy”. It states that you can rely on the reasons up to.

However, while “supporting a flexible approach to allogeneic and heterologous vaccine schedules,” combination vaccines “should only be implemented with careful consideration of current vaccine supply and vaccine supply forecasts …” [and] Potential benefits and risks of the particular product used. “

In response to Twitter’s question about booster selection, Agrawal said, “Given all factors, including age group, risk, availability, etc., the relevant committee will call immediately.” According to the Vaccine Platform Report, there is a consensus among Indian authorities that the first and third booster dose, if cleared, should be a different vaccine than the flagship Covishield, Covaxin and Sputnik V. there is. Of the national Covid vaccination campaign.

Explaining the logic behind this, experts said India Express Vaccines like the Covishield use an attenuated virus that catches colds in chimpanzees, but because they are harmless to humans, they are used as a means of introducing the new coronavirus spike protein into the human immune system. Virus — The extra jab of the vaccine also has the effect of strengthening the immune response to the chimpanzee virus. In that regard, it may be better to use a different type of vaccine for the third dose.

According to the report, the protein-based vaccines Corbevax and Covovax, manufactured by Hyderabad-based Biological E, are “India’s best bet against booster shots.”

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