Covid-19, in America we start with the third “mixed” dose

by time news

While developing countries have not yet reached 5% vaccinations for the entire population, developed countries, Europe and the United States in particular, after averaging over 70% of immunized people are planning a third booster dose. .

Generally we intend to leave, and in some cases we have already left (see Italy and Israel), with over 80, immunosuppressed, categories weakened by particular pathologies and health personnel. But the tendency is to bring the appeal to a much wider and heterogeneous audience.

One of the questions that are arising with this new address is to understand with which vaccine the booster can be done. Will it be necessary to do the same or will it be possible to receive the dose of a different product?

The third dose of vaccine with different products

America has given an answer these days.

According to reports from the New York Times and Wall Street Journal, the Food and Drug Administration (FDA) has planned to allow all Americans to receive the third dose with a different vaccine than they originally had.

The FDA announcement is expected as early as this week confirming that the third dose will be free of any brand of vaccine. In the same communication, the go-ahead for booster doses with Moderna, Johnson & Johnson should also be provided after the ok already given for Pfizer-BioNTech.

The National Institutes of Health presented the results of a “mix and match” study of vaccine brands against Covid-19. The research, communicated by FDA experts, found that people vaccinated with a single dose of Johnson & Johnson and who received a booster of Moderna increased their antibodies 76-fold in 15 days, compared to a four-fold increase. .

The study also concluded that one dose of Pfizer-BioNTech also increases the antibody levels of the Johnson & Johnson vaccine more than Johnson & Johnson itself, albeit with less potency than Moderna.

The third dose with different vaccines

The FDA had already allowed the mix of booster vaccines with third dose of Pfizer-BioNTech a month ago for those over 65, for people at high risk of serious illness and for people highly exposed to contract the virus, as well as all staff. sanitary.

But the US regulatory agency plans to expand the number of booster doses and especially that of people immunized with a reinforcement dose.

The recommendations that the FDA should confirm will mainly be to wait six months after receiving the second dose to get a third of Pfizer. While only two months should be enough for Moderna and Johnson & Johnson.

In Europe, however, the modus operandi is not yet clear, especially for those who have been vaccinated with Astra Zeneca, which now seems to have disappeared.

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