Filenews 21 November 2021
In the FDA's new guidelines, mRNA vaccines from Pfizer and Moderna received approval for a booster in all adults after completing their vaccination with an approved COVID-19 vaccine.
The doctors of the Therapeutic Clinic of the Medical School of the National and Kapodistrian University of Athens, Theodora Psaltopoulou, Panos Malandrakis, Giannis Danasis and Thanos Dimopoulos (Rector of the University of Athens) summarize the relevant announcements.
The approval of the booster dose is aimed at providing continuous and better protection against severe disease, especially as immunity declines over time six months after people are vaccinated with the Pfizer or Moderna vaccines, or two months after vaccination with the Johnson vaccine.
The decision on the booster dose for all was based on immunological response data brought about by the vaccines.
In Moderna's case, the 149 participants who received the extra dose at 6 months in the approval clinical trial were compared to the 1,055 who simply completed the vaccination regimen, who one month after the amplification dose increased the antibody response.
Similarly, as far as Pfizer is concerned, data from 200 people who received the third dose and had a better antibody response were analyzed.
Data from a prospective randomized trial by the Pfizer Company was presented in which 10,000 volunteers who had received the second dose of the vaccine were randomized half to receive a third dose and the other half to receive an inert excipient (placebo).
Disease (but without the need for hospitalization) was found in six people out of the 5,000 people who received the third dose of the vaccine compared to 123 people out of the 5,000 people who received a placebo (i.e. they did not receive a third dose of vaccine). Therefore, the administration of a booster dose of the vaccine was 95% effective in preventing sars-CoV-2 disease.
As regards the cases of pericarditis/myocarditis that have been described after administration of mRNA vaccines, newer data indicate that these are two cases per 1 million doses of vaccines.
The usual side effects after the enhancement dose were pain, redness and swelling at the vaccine site, fever, headache, myalgias, arthralgias and more often than the initial doses of axillary lymphadenopathy consonant with the site of vaccination.
The RECOMMENDATION of the CDC is that adults over 18 years of age have the possibility to take the booster dose six months after the second dose, while for adults 50 years and older there is a strong recommendation to administer the booster dose.
