The FDA (American drug and food regulatory agency) authorized this Wednesday (31), in an emergency, the application of versions of vaccines against Covid adapted to the omicron variant.
The immunizer developed by pharmaceutical Moderna can be applied in the United States to individuals over 18 years of age and that of Pfizer to those over 12 years of age. In both cases, the application must be carried out at least two months apart from the last dose.
The two companies’ vaccines use messenger RNA (mRNA) technology, which allows them to mimic the spike protein -used by the virus to attach itself to our cells and invade them-, activating the body’s defense system. The difference of the new immunizers is that they contain two mRNA sequences: one coding for the original spike protein and the other for the spike protein of the BA.4 and BA.5 lines of the omicron.
According to the FDA, the BA.4 and BA.5 strains are the ones that cause the most deaths in the US today and are expected to have the most circulation during the fall and winter months. With the measure, the agency expects an increase in protection during this colder period.
“We have more than two years of a pandemic and it is to be expected that vaccines will be updated because the virus mutates. Today, we still see vaccines targeting ancestral strains, the Wuhan strain. They continue to protect us from serious forms, deaths and hospitalizations. , but the duration of protection has been very short, so much so that we have called the population for booster doses”, says infectious disease specialist Rosana Richtmann, a member of the SBI (Brazilian Society of Infectious Diseases).
The doctor also explains that the greater amount of antibodies can lead to longer protection and, if this is confirmed, it will be one of the great advantages of these updates.
In the statement, the FDA states that it made the decision to authorize the immunizers considering the evidence on the positive effects of the two companies’ monovalent vaccines, studies with a bivalent vaccine coding for the BA.1 lineage, similar to BA.4 and BA. .5, and data from preclinical studies with selected strains.
The CDC (Centers for Disease Control and Prevention) will discuss this Thursday (1) whether to recommend the two new vaccines in American territory.
In Brazil, Pfizer filed on the 19th with Anvisa (National Health Surveillance Agency) a request for the use of the bivalent vaccine for the ômicron BA.1 variant. “It is worth mentioning that the current contract for the supply of vaccines from Pfizer to Brazil includes the delivery of potential vaccines adapted and/or for different age groups”, said the pharmacist at the time.
For Richtmann, if the studies confirm prolonged protection of bivalent vaccines, it would be possible to plan annual vaccination campaigns against Covid together with those of the flu, for example.
“MRNA vaccines are here to stay. One of the greatest legacies of the pandemic is the new vaccine technologies not only for the subvariants of the omicron, but also for other microorganisms. The speed of development of new vaccines from now on will be much faster because it is much easier to adjust a vaccine with this technology than to make another with an inactivated virus”, evaluates the infectologist.