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Biden tests positive for Covid again despite taking Pfizer antiviral

US President Joe Biden, 79 years old, showed a resurgence of Covid virus replication 19 after taking the antiviral Paxlovid, from Pfizer, informed the doctor of the presidency Kevin O’Connor in an official note. After four negative results for the test from Tuesday to Friday, the test was positive for the presence of the virus antigen late Saturday morning (30).

O’Connor reports that the head of state has had no re-emergence of symptoms, despite this. The “rebound” of the infection would happen in “a small percentage” of patients treated with Paxlovid, which has two active ingredients that work together. In the original drug development study, this happened to 1% to 2% of patients.

Biden, who had been released from isolation because of negatives three days ago, returns to isolation for more five as recommended by the guidelines of the Centers for Disease Control and Prevention (CDC) in the country. Two presidential trips had to be cancelled. Before the positive test, he was holding meetings at the White House wearing a mask, but confident enough to remove it on Thursday during a meeting with executives.

The president has already had four doses of the mask. Pfizer mRNA vaccine: two doses just before inauguration in January 2021, a booster dose in September and another at the end of March this year. The omicron variant, which now dominates the pandemic with its subvariants, is less lethal than previous variants. As it accumulates changes in its genetic material, especially in places used by the immune system to neutralize the disease, it is able to better circumvent defenses acquired by vaccines or previous infections.

In a June publication in a medical journal from the group The Lancet, Swedish researchers compared immunity acquired with previous infection (natural immunity) and hybrid immunity, which is combined with vaccines, in a sample of millions of individuals. They concluded that reinfection and hospitalization of people who had Covid and recovered “remained low for up to 20 months.” Vaccination lowered that risk a little more for nine months, but the difference in numbers was small. Scientists recommend that, if there are restrictions based on proof of immunity, pre-infection is just as good as vaccination, and that it would be wrong to assume that only the vaccinated are immunized.

Vaccines that are “sieves” holes”, which do not prevent infections, are a source of concern. In an article published in the journal PLoS Biology in 2015, in which they analyzed a virus that affects chicken, Andrew Read, from the State University from Pennsylvania, and colleagues have shown that vaccines with partial reduction of virus transmission allow for a natural selection environment that favors more lethal variants.

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