December 8, 2023

Health experts around the world are sounding the alarm as they begin to report that Omicron BA.5, the strain of coronavirus that is currently outpacing other variants in infection and has become the dominant strain in the US and abroad, has the ability to re-infect people within weeks of contracting the virus.

Andrew Roberston, the chief health officer in Western Australia, said that while it was previously believed that most people would retain some level of protection against re-infection if they were vaccinated or had retained some level of natural immunity due to a recent contraction of the virus, this was not the case with the latest strain.

“What we are seeing is an increasing number of people who are infected with BA.2 and then become infected after four weeks,” the doctor explained during an interview with the Australian news agency. “So maybe six to eight weeks they develop 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 people who in previous waves of Covid-19 had stronger immunity has led some experts to start calling this latest strain the most contagious yet.

“They’re taking over, so they’re clearly more contagious than previous variants of the microbe,” David Montefiori, a professor at the Human Vaccine Institute at Duke University Medical Center, said in an interview with NBC News.

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

And although the average number of new cases recorded in the U.S. each day has been steady at around 95,000 to 115,000, according to data from The New York Times, Experts fear that a combination of home testers not reporting positive cases, the closing of government-sponsored testing centers and an increase in states stopping daily data updates has given them a less accurate picture of how much this new strain is infiltrating. really in the country.

A study published in Science Last week confirmed the disturbing reality that many may already have experienced anecdotally with multiple reinfections: these two new subvariants evade protection from previous infections and vaccines.

Immunology professor Danny Altmann, a co-author who wrote the Science The paper, along with Rosemary Boyton, professor of immunology and respiratory medicine, discussed the findings from their research in a recent article. They noted that, contrary to the popular belief that vaccines and prior infection would provide “a wall of immunity,” nations are instead experiencing “wave after wave of new cases.”

In the study, Professor Altmann explains how they followed people who were triple-vaxxed and those who suffered unprecedented infections during previous Omicron waves.

“This allows us to examine whether Omicron was, as some hoped, a benign natural booster of our immunity to Covid,” he wrote in The guardian. “That turns out not to be the case.”

“Most people – even when triple-vaccinated – had 20 times less of a neutralizing antibody response to Omicron than to the original ‘Wuhan’ strain,” said Mr. Altmann, noting that, importantly, “infection by Omicron was a poor immune booster for further Omicron. infections”.

“It’s kind of a stealth virus that goes under the radar,” he said, stressing that “even with Omicron, we’re not well protected from further infections.”

Mr. Altmann’s research appears to confirm other recent studies released in recent weeks that have warned of the ability of new sub-variants to evade protection from earlier immune-boosting precautions. i.e. vaccination and natural immunity.

Research published in Nature from Columbia University, a yet-to-be-peer-reviewed study suggests that BA.4 and BA.5 are four times more resistant to vaccine antibodies than BA.2, a subvariant that became the dominant strain in the U.S. in April, replacing the original strain that had driven the winter wave across the country.

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

“Our data suggest that these new Omicron subvariants will likely be able to drive outbreaks of infection in populations with high levels of vaccine immunity as well as natural BA1 and BA2 immunity,” said Dr. Dan Barouch. CNN. “It is likely that vaccine immunity will still provide substantial protection against severe disease with BA4 and BA5.”

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

Because of this, the vaccines that many received in the last 18 months will likely need not only a boost, but also an update.

The Federal Drug Administration recommended last week that the makers of the Covid-19 vaccines, namely Pfizer and Moderna, begin modifying what they currently offer so that their booster shots can more accurately target the BA.4 and BA.5 variants and estimated that these vaccines could become available as early as fall.

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