February 7, 2023

Health experts around the world are signaling concern when they begin reporting that Omicron BA.5, the coronavirus strain that currently outnumbers other variants in infection and has become the dominant strain in the United States and abroad, has the potential to re-infect people within weeks of coming into contact with the virus. .

told Andrew Robertston, Western Australia’s chief health officer News.com.au Although previous wisdom had been that most people would retain some level of protection against reinfection if they were vaccinated or retain a certain level of natural immunity due to the recent contraction of the virus, this has not been the case with the most recent twist.

“What we’re seeing is an increasing number of people who have had BA.2 and then been infected four weeks later,” the doctor explained during an interview with the Australian News Agency. “So maybe six to eight weeks later they get a second infection, and that’s almost certainly BA.4 or BA.5.”

The ability of the BA.4 and BA.5 strains to re-infect individuals who had stronger immunity in previous waves of Covid-19, has led some experts to begin naming this latter strain as the most transmissible to date.

David Montefiore, a professor at the Institute for Human Vaccines at Duke University Medical Center, said in an interview NBC News.

Federal estimates released by Center for Disease Control and Prevention Tuesday showed that BA.5 has now overtaken as the dominant strain in the United States, accounting for about 54 percent of cases for the week ending July 2, 2022.

And while the average number of new cases the United States records each day has steadily hovered around 95,000 to 115,000, according to data from New York timesAnd the Experts fear that a combination of home testers not reporting positive cases, the closing of government-funded testing centers, and a slight spike in states halting daily data updates have led to a less accurate picture of just how much this new strain has penetrated the nation.

A study was published in Sciences Last week confirmed the troubling fact that many people may already be suffering with repeat infections: these two new subvariables evade protection from previous infections and vaccines.

Immunology professor Danny Altman, co-author who formulated Sciences The research paper along with Rosemary Boyton, Professor of Immunology and Respiratory Medicine, discussed the findings of their research in a recent opinion piece. They noted that, contrary to popular belief that vaccines and previous infections would provide a “wall of immunity,” countries are instead experiencing “wave after wave of new cases.”

In the study, Professor Altman explains how they followed individuals who had been subjected to the triple vaccination and those who had experienced sudden infections during previous omicron waves.

“This allows us to examine whether Omicron is, as some had hoped, a benign natural booster for our Covid immunity,” he wrote in. Watchman. “It turns out that’s not the case.”

“Most people—even when they received the DTP vaccine—had a 20-fold lower response to neutralizing antibodies against omicron than the initial Wuhan strain,” Altmann said, noting that “omicron infection was weak immune suppression to increased omicron infections.”

“It is a kind of under-the-radar virus,” he said, stressing that “even with Omicron, we are not well protected from further infections.”

Altman’s research appears to confirm other recent studies released in recent weeks that caution against the ability of new sub-variants to evade protection from previous immune-building precautions; They are vaccination and natural immunity.

Posted in temper nature from Columbia University, a study not yet peer-reviewed, reports that BA.4 and BA.5 are four times more resistant to antibodies than vaccines than BA.2, the variant that became the dominant strain in the United States in April to replace The original strain that drove the winter wave across the country.

Although experts believe that these current strains are likely to fuel new waves, they note that the vaccines will provide partial immunity and can protect against potentially more serious infections.

“Our data suggest that these new Omicron sub variants are likely to lead to increased infection in populations with high levels of vaccine immunity in addition to normal BA1 and BA2 immunity,” said Dr. Dan Baruch. CNN. “Vaccine immunity will likely continue to provide significant protection against severe disease with BA4 and BA5.”

Dr. Barouch was one of the co-authors of a separate paper, published with New England Journal of Medicinewhich found that there was a threefold decrease in neutralizing antibodies from vaccines and infection against BA.4 and BA.5, which was significantly lower than that of BA.1 and BA2.

For this reason, it is likely that the vaccines many have received in the past 18 months do not need a booster, but rather an update.

The Federal Drug Administration Last week recommended that the makers of the Covid-19 vaccine, Pfizer and Moderna, begin modifying what they currently have so that the booster shots could more accurately target the BA.4 and BA.5 variants and estimated that these shots could become available as early as the mid autumn.

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