Health experts around the world are sounding the alarm as they begin to report that Omicron BA.5, the coronavirus strain that currently outpaces other strains of infection and has become the dominant strain in the United States and abroad, has the ability to reinfect people within weeks of being infected by the virus.
Andrew Roberston, Western Australia’s chief health officer, told News.com.au that although previous wisdom held that most people would retain some level of protection against reinfection if they were vaccinated or had retained some level of natural immunity due to of a recent contraction of the virus, this has not been the case with the latest strain.
“What we are seeing is an increasing number of people who have been infected with BA.2 and then become infected after four weeks,” the doctor explained during an interview with the Australian News Agency. “Then maybe six to eight weeks they develop another infection, and it’s almost certainly BA.4 or BA.5.”
The ability of the BA.4 and BA.5 strains to re-infect individuals who in previous waves of Covid-19 would have had stronger immunity has led some experts to call this latest strain the most transmissible yet.
“They’re taking over, so clearly they’re more infectious than previous variants of omicron,” David Montefiori, a professor at the Human Vaccine Institute at Duke University Medical Center, said in an interview with NBC News.
Federal estimates released by the Center for Diseases Control and Prevention on Tuesday show that BA.5 has now passed 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 U.S. records each day has been steady at about 95,000 to 11,500, according to data from New York Times, experts fear that a combination of home testers not reporting positive cases, a shutdown of state-funded testing centers and an increase in states halting their daily data updates has led to a less accurate picture of how much this new strain is actually entering the country.
A study published in Science last week has confirmed the disturbing reality that many may have already experienced anecdotally with multiple back-to-back reinfections: these two new sub-variants evade protection from previous infections and vaccines.
Immunology professor Danny Altmann, a co-author who wrote Science paper along with Rosemary Boyton, a professor of immunology and respiratory medicine, discussed the findings of their research in a recent op-ed. They noted that, contrary to a popular belief that vaccines and previous infection would provide “a wall of immunity”, nations are instead experiencing “wave after wave of new cases”.
In the study, Prof Altmann explains how they followed individuals who tripled and those who suffered breakthrough infections during previous Omicron waves.
“This allows us to investigate whether Omicron was, as some hoped, a benign natural enhancer of our Covid immunity,” he wrote in Guardian. – It turns out that is not the case.
“Most people — even when triple-vaccinated — had 20 times less neutralizing antibody response to Omicron than to the original ‘Wuhan’ strain,” Altmann said, noting that, importantly, “Omicron infection was a poor booster of immunity to promote Omicron infections”.
“It’s a kind of stealth virus that comes in under the radar,” he said, stressing that “even after having Omicron, we are not well protected against further infections”.
Altmann’s research appears to confirm other recent studies that have been released in recent weeks that warn of the new subvariants’ ability to evade protection from earlier immune-building precautions; namely 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 United States in April, replacing the original tribe that had driven the winter wave across the country.
Although experts believe that these current strains are likely to 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 are likely to lead to increases in infections in populations with high levels of vaccine immunity as well as natural BA1 and BA2 immunity,” Dr Dan Barouch told CNN. “It is likely that vaccine immunity will still provide significant protection against severe disease with BA4 and BA5.”
Dr Barouch was one of the co-authors on a separate paper, published with New England Journal of Medicinewho found that there was a threefold increase in neutralizing antibodies from vaccines and infection against BA.4 and BA.5, which was significantly lower than BA.1 and BA2.
Because of this, vaccines that many people received in the past 18 months are likely to need not just a boost, but an update.
The Federal Drug Administration recommended last week that Covid-19 vaccine makers, 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 shoots can already be available in mid-autumn.