The U.S. Food and Drug Administration (FDA) authorized on Wednesday the administration of a booster shot from a different COVID-19 vaccine for those who have already received their initial vaccination. This approval implements a "mix and match" strategy among the three vaccines permitted in the country.
The FDA stated in a release that it concluded the "known and potential benefits of using a heterologous single booster dose outweigh the known and potential risks for the eligible population." Currently, three COVID-19 vaccines have been authorized in the United States: Pfizer, Moderna, and Johnson & Johnson. This decision means that individuals who received two doses of Pfizer or Moderna, or one dose of Johnson & Johnson, can now receive a booster dose from one of the other vaccines.
In its announcement, the FDA also permitted the booster dose for all adults (18 years and older) who were vaccinated with Johnson & Johnson, as well as for at-risk individuals who received two doses of Moderna, particularly seniors. With this decision, the United States has completed its strategy for the booster vaccination campaign, following a previous month's allowance for certain groups who had received two doses of Pfizer to obtain a third booster shot of the same vaccine.
This is the first time the U.S. has authorized "mixing" vaccines, a step that many other countries have already taken. These countries have not only allowed this mixing for the third booster dose but also for the second dose. The decision made on Wednesday is expected to attract the interest of more than 15 million Americans who received the Johnson & Johnson vaccine.
A U.S. study published last week indicated that recipients of this single-dose vaccine may be interested in receiving a booster shot from one of the other two vaccines, which utilize a different mRNA technology, to enhance their antibody levels.
According to Wednesday's decision, all individuals aged 18 and above who received a dose of Johnson & Johnson at least two months ago can now receive an additional shot of one of the three authorized vaccines. For individuals who received their second dose of Moderna at least six months ago, there are three categories eligible for a booster: seniors aged 65 and above, adults aged 18 to 64 who are at "high risk" for severe disease, and those who, due to their job or situation, are "frequently" exposed to the virus.
These criteria are the same as those previously set by the FDA when it allowed these three groups to receive a third dose of the Pfizer vaccine. The last group includes supermarket workers, healthcare workers, prisoners, and those residing in homeless shelters. The Moderna booster dose will actually be half a dose (50 micrograms compared to 100 micrograms for each of the first two doses).
