March 23, 2023

Health experts around the world are starting to sound the alarm, and they are starting to report that the coronavirus strain Omicron BA.5, which is now infecting faster than other variants and has become the dominant strain in the U.S. and abroad, has the ability to re-infect people with the virus within weeks.

WA Chief Health Officer Andrew Roberston told news australia While previous wisdom held that most people would retain some degree of protection against reinfection if they were vaccinated or retained some degree of natural immunity due to a recent viral infection, this has not been the case recently. tight.

“What we’re seeing is more and more people are getting infected with BA.2 and then after 4 weeks,” the doctor explained in an interview with the Australian news outlet. “So they could have a second infection in six to eight weeks, which is almost certainly BA.4 or BA.5.”

The ability of strains BA.4 and BA.5 to re-infect individuals with stronger immunity from previous waves of Covid-19 has led some experts to start calling this latest strain the most contagious yet.

David Montefiore, professor at Duke University Medical Center’s Human Vaccine Institute NBC News.

Federally Published Estimates Centers for Disease Control and Prevention BA.5 has now replaced the U.S. as the dominant strain, accounting for about 54% of cases in the week ending July 2, 2022, it showed on Tuesday.

According to from New York Times, Experts are concerned that the lack of positive cases reported by home testers, the closure of government-funded testing centers and states halting the increase in daily data updates have led to an inability to know exactly how far the new strain has actually penetrated the country.

A study published in science Last week confirmed a disturbing reality that many people may have experienced multiple back-to-back rumours of reinfection: The two new subvariants evade previous infections and the protection of vaccines.

Danny Altmann, professor of immunology science The paper, published with Rosemary Boyton, a professor of immunology and respiratory medicine, discusses their findings in a recent op-ed. They noted that, contrary to the popular belief that vaccines and previous infections would provide an “immunity wall”, countries were experiencing “waves of new cases”.

In this study, Prof. Altmann explains how they tracked people who had been triple-vaccinated in the early Omicron waves and those who had a breakthrough infection.

“This allows us to examine whether Omicron is, as some hoped, a benign natural booster of our immunity to Covid,” he said in a statement. protector. “It turns out not to be the case.”

“Most people – even with the triple vaccine – had 20-fold less neutralizing antibody responses to Omicron than to the original ‘Wuhan’ strain,” Mr. Altmann said, noting that, importantly, “Omicron infection does not work well for further Omicron immunity enhancement. Infection”.

“It’s a stealthy virus, sneaking under the radar,” he said, stressing that “even with Omicron, we’re not very good at preventing further infections”.

Mr Altman’s research appears to confirm other studies published in recent weeks that warn that new sub-variants are able to evade protection from previous immune-building precautions; namely vaccination and natural immunity.

Research published in nature A not-yet-peer-reviewed study from Columbia University showed that BA.4 and BA.5 were four times more resistant to vaccine antibodies than BA.2, a strain that became the dominant strain in the United States in April. A sub-variant that replaces the original strain that drove winter waves across the country.

While experts believe these current strains could spark a new wave, they do note that a vaccine will provide partial immunity and still prevent potentially more serious infections.

“Our data suggest that these new Omicron subvariants may lead to a surge in infection in populations with high levels of vaccine immunity as well as natural BA1 and BA2 immunity,” said Dr. Dan Barouch CNN. “Vaccine immunization is likely to still provide substantial protection against severe disease in BA4 and BA5.”

Dr. Barouch is one of the co-authors of another paper with New England Journal of Medicinefound that neutralizing antibodies from the vaccine and infection against BA.4 and BA.5 were reduced by a factor of three, significantly lower than in BA.1 and BA2.

As a result, the vaccines that many people received in the past 18 months may need not only a booster, but also an update.

This Federal Drug Administration Covid-19 vaccine makers, namely Pfizer and Moderna, were advised last week to start modifying their current offerings so that their booster shots could more accurately target the BA.4 and BA.5 variants, estimating that these vaccines could be used as early in mid-autumn.

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