Four COVID-19 particles in a pink and blue background.
Illustration: PGN

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What you need to know 

  • The U.S. is seeing over 134,000 new COVID-19 cases daily, and BA.5 is the dominant subvariant among them. Ohio, West Virginia, Wisconsin, and Kansas are among the states seeing the biggest increases in cases.
  • One of the main differences between BA.5 and other strains is that its spike protein can more easily latch onto a person’s cells and evade some of the person’s immune responses.
  • So far, the strain doesn’t seem to be causing more severe COVID-19 cases. Vaccination continues to protect against severe disease and death from the virus. 

BA.5 is the most contagious COVID-19 subvariant we’ve seen, and it’s causing a significant spike in cases across the U.S. The subvariant, which was first detected in South Africa in January, is one of many COVID-19 mutations, but its anatomy—particularly differences in its spike protein—allows it to more easily attach to a person’s cells, and therefore it has a higher capacity to evade immunity from past infection or vaccination. But so far, BA.5 doesn’t seem to be causing more severe disease, and we now have many tools available to protect ourselves. 

Here’s everything you need to know about BA.5 and the COVID-19 wave it’s causing across the country.  

To what extent is BA.5 spreading in the U.S.?

BA.5 is now the dominant subvariant in the United States, and experts say it’s the most transmissible COVID-19 strain yet. In mid-May, BA.5 was responsible for 1 percent of cases in the United States, and in the week ending July 16, the strain accounted for 77.9 percent of cases in the country. According to the New York Times, infections are rising in at least 40 states, particularly in the Great Plains, West, and South. BA.5 is causing the current surge, with over 134,000 new COVID-19 cases daily.

Why is BA.5 so contagious?

BA.5 is one of many COVID-19 virus mutations, but what makes it different from other subvariants is its spike protein: a virus molecule in charge of attaching to a person’s cell. BA.5’s spike protein allows it to more easily latch onto a person’s cells and evade some of the person’s immune responses from previous infection or vaccination. Experts consider the subvariant a “fitter” version of other COVID-19 variants, which means that it can better grow, evade immunity, and be transmitted. The good news is that while BA.5 is highly contagious and rapidly spreading, it seems to not cause more severe COVID-19 illness in the U.S.

What can people do to protect themselves against BA.5?

We have lots of tools at our disposal to fight the BA.5-driven surge. It’s important for everyone older than 6 months to get vaccinated and for people over 5 years old to get their first booster shot. People over 50 years old and those who are immunocompromised should also get their second booster shot. To lower your chances of getting infected and spreading the virus, you should wear high-quality masks (like a KN95 or N95 mask) in indoor spaces, in crowded places, and when traveling—even if they’re not required. Finally, if you test positive and are at high risk or immunocompromised, you can be treated with antiviral pills like Paxlovid or Lagevrio (molnupiravir) to prevent severe disease. They should be taken within five days of testing positive.