The US Food and Drug Administration’s main scientific advisory committee voted to reject the public use of Pfizer’s mRNA vaccine “booster”-a move that may disappoint some public health experts who are pushing for a third dose of vaccine to help slow vaccination. The spread of COVID-19.
On September 17, 2021, an independent committee of doctors, scientists, and public health experts voted 16 to 2 against the full use of the third dose of the vaccine, which is now branded as “Comirnaty”. However, the panel does recommend that Americans 65 years and older or those at high risk of severe COVID-19 get this vaccine. In advising the public not to vaccinate, the committee cited a number of reasons, such as the lack of adequate safety data among young people, and signs that the initial dose still seems to provide strong protection against serious diseases that lead to hospitalization and death. The team also agreed in a poll (but not a formal vote) that boosters are beneficial to certain groups of people, such as health care workers and other occupational exposure high-risk groups.
Although the vote is not binding, it is likely to become the basis for the FDA’s formal recommendations.
As an immunologist who studies COVID-19 and the immune response to vaccination, I think the promotion of booster immunization is predictable, although the voting results are always uncertain. In the past year, important research and public reports have focused on the durability of the immune response after the first and second doses of the COVID-19 mRNA vaccine. This work is essential for scientists to understand how long the immune response of vaccination can provide protection, and whether this protection extends to new and emerging variants of the SARS-CoV-2 virus.
The good news is that mRNA vaccines do seem to be able to continue to be effective against serious illness or death caused by the new coronavirus, including highly infectious delta variants.
But the data on this protection life is more complicated and the scope is still limited. Although there are signs that vaccinators are building an immune “memory”—it is almost certain to provide partial protection in the long run—the antibodies responsible for stopping the spread of the virus before the infection occurs appear to be several months after the second vaccination. The dose is gradually reduced within.
This is not surprising to immunologists and does not mean that the vaccine will not work. Antibodies will weaken with the normal course of the immune response to any vaccine. This is why you need to get a tetanus booster every ten years or so, and why the measles, mumps, and rubella vaccines are given in three doses instead of two.
The question is just how fast the antibodies are falling, and when they no longer provide adequate protection. At that time, it is recommended to inject an additional dose of vaccine to “increase” the number of antibodies and restore them to a protective level. In this case, widespread reports of breakthrough infections (infections in individuals who have been fully vaccinated), as well as research on the possibility of reduced immunity among people vaccinated in the early stages of the pandemic, have led to the need for enhanced vaccines The discussion quickly became the focus.
In the context of this mixed data, the FDA team had to weigh the risks and benefits of enhanced injections. Although the third dose of the vaccine is the same as the fully approved vaccine-and therefore considered safe-they will not be without side effects similar to the first and second doses.
In addition, after the first vaccination, serious diseases documented in rare and isolated cases, such as myocarditis (a type of inflammation of the heart), may also occur after boosting immunizations. In addition to the controversy surrounding the absolute benefits of the third shot to maintain the current level of protection for other healthy vaccinators, this has also led many public health officials to express concerns that the review is premature and may further confuse and alienate Americans who have been divided. people.
Separate politics from data
Since the Biden administration publicly supported the third dose of vaccine for all vaccinated Americans in August, the committee’s task is to separate politics from data to weigh whether the benefits of enhanced injections outweigh the already hesitant American public. risks of.
In rejecting the proposal, the FDA team has expressed confidence in the original vaccination process of healthy individuals and will wait for more data before identifying the decline in antibody levels as a major threat to public safety. However, it supports an increase in people at high risk of exposure to COVID-19, which shows that people recognize that additional injections may be needed to fully protect the general public.
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