Around the world, Omicron’s latest subvariant BA.5, has been fast becoming the most dominant SARS-CoV-2 strain. According to the U.S. Centers for Disease Control and Prevention, the latest estimate from the CDC, BA.5 now accounts for more than half the new COVID-19 patients. That’s up 10 percentage points compared to the prior week.
For several reasons—including a lack of protective mandates and mutations in the virus—BA.5 may now be tricky to get under control.
The power of BA.5 (and its sibling BA.4, which makes up about 16% of new U.S. cases, has the same spike protein mutation as BA.5, but doesn’t seem to spread as quickly) is its ability to infect, and reinfect, almost anyone. This highly contagious strain can evade people’s built-up immunity, whether from vaccination or previous infection. This is what it looks like Nature reports, lab studies show that even people who have so-called “hybrid immunity” from vaccination and a past infection with the Omicron BA.1 strain are less able to ward off reinfection from either the BA.4 or BA.5 strains. Experts believe this is due largely to changes in the virus’ spike proteins. Current COVID-19 vaccines and boosters target the original strain of the virus rather than any of the variants, so being vaccinated doesn’t offer as much protection as it once did against infection. (Fortunately, vaccines offer broad protection against some of the worst consequences of the disease.
Since BA.4 and BA.5 have taken over, “we have seen some cases of reinfection,” Dr. Wesley Long, an experimental pathologist at Houston Methodist Hospital, told CNN, “and I have seen some cases of reinfection with people who had a BA.2 variant in the last few months.”
Combine the virus’ greater transmissibility and more immune evasion with fewer protective mandates across the country, and the threat of infection is high. New variants are likely to develop as the virus continues its spread. Research that hasn’t been peer reviewed yet found that COVID-19-infected people had higher rates of death and hospitalization after being infected twice. These people were more likely to have new, long-lasting health problems such as lung or heart disease, fatigue, digestion and kidney problems, diabetes and other neurologic issues.
The virus is causing a lot of concern for vaccine manufacturers. The U.S. Food and Drug Administration (FDA), stated that booster shots must be developed for fall to target both BA.4 and B.5. But while companies are developing new vaccines to specifically address Omicron, it’s still unclear how effective they will be in tackling the more recent subvariants, or, if the virus keeps evolving so rapidly, whether anything developed now will be outdated by the time it’s available.
The hopeful news is that from what experts can tell so far, the BA.5 variant isn’t causing a more severe form of infection (although scientists are still gathering more data on this), the reported symptoms haven’t changed much, and death and hospitalization rates in the U.S. are lower than they were during the winter Omicron wave. According to the CDC, there has been a slight increase in hospitalizations recently.
Experts can be reached at recommendPeople over 50 should not wait to get their boosters as the infection risk is very high.
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