A booster dose may increase the risk of reinfection with

Covid vaccine may pose risk of stroke, CDC and FDA say

PfizerBioNTech’s bivalent vaccine against Covid19 could increase the risk of stroke in people aged 65 and older, the two main health authorities in the United States, CDC, reported last Friday (13) in a joint statement (Centers for Disease Control and Prevention) and FDA (Food and Drug Administration).

Government agencies discovered a “safety signal” (i.e., a signal of potential risk in using the vaccine) that “could be due to factors other than the vaccine itself.” The warning came from the CDC’s realtime vaccine surveillance system, which found that patients in this age group who received the bivalent dose were more likely to have an ischemic stroke within 21 days of vaccination, compared with the period 22 to 42 days later . Ischemia is the technical term for damage caused by lack of blood flow to a part of the body due to blockage of local arteries.

The signal wasn’t detected for Moderna’s bivalent vaccine, which is odd because it’s also mRNA (a small piece of the virus’s genetic material) and is more concentrated, so the side effects of Pfizer’s vaccine tend to be more pronounced are than that of the competitor. CDC and FDA also note that this sign has not been observed in previous studies. However, these studies do not have the highest scientific rigor.

The two health authorities advise against changing current vaccination policies based on this signal. The CDC “recommends that everyone be up to date on their Covid19 vaccinations by the age of six months.” They end the joint note with statistics favoring the effectiveness of Covid vaccines against death and serious illness, and compare them to Data from unvaccinated individuals without mentioning the protection conferred also by previous infection.

Critics of U.S. federal government policy are taking note

Joseph Ladapo, surgeon general of Florida, a Republican state that has had less harsh policies than Democratic states in the pandemic, commented wryly, “What better time than a Friday afternoon for the CDC and the FDA, to Americans.” to inform that the doses of mRNA that [os órgãos] could cause stroke? Don’t worry, we’ll make sure to share it like we’ve been doing for months.”

However, the causal relationship has not yet been proven. In vaccine studies, as reported by the People’s Gazette By covering Pfizer vaccine production documents obtained through the Access to Information Act, surveillance encompasses a variety of adverse events. In fact, everyone reported in this case, a child who swallowed a coin and an elderly person struck by lightning was trapped. After further investigations, a causal relationship between vaccination and adverse events is excluded or confirmed. If they are confirmed, they are now called side effects. Such is the case with the side effect of vaccine myocarditis, an inflammation of the heart that affects a proportion of young men.

They are also not mistaken when they say that side effects are rare. However, severe disease is also rare in some groups, particularly with the advent of the milder Omicron variant a year ago. One rarity may be greater than the other and comparison between them may change the costbenefit picture for each case and raise serious doubts about a coherent vaccination policy for all age groups “from six months”.

It’s understandable that health authorities are cautious about sending the safety signal, but they don’t understand their failure to conduct studies of the highest scientific rigor, says Vinay Prasad, a physician and professor of epidemiology and biostatistics at the University of California, San Francisco. “This government’s vaccination policy has been horrendous and has always made the mistake of promoting doses,” the scientist said in his own publication. Evidence of this was when two FDA board scientists, Marion Gruber and Phil Krause, left their positions in protest when the Biden administration ignored their opinion and recommended a third dose widely available to the general public.

Vinay also criticizes Pfizer itself for not conducting the most rigorous studies. Regarding the new safety signal, the expert points out that the raw data has not been released and there is a lack of salutary information. “What is the absolute risk? Where’s the press conference? Unfortunately, they didn’t provide any additional information,” he laments. “If that safety signal proves salient, reputation [dos órgãos] will be in ruins”.

Authorities approved the bivalent dose of both vaccines for children as young as five years of age only based on rodent studies. They assumed that the previous safety data for the mRNA dose based on the first virus variant would also apply to the bivalent one, which includes the mRNA of the omicron variant.