New omicron subvariants are spreading rapidly in the United States, worrying experts about the degree of transmissibility amid the ongoing pandemic.

Driving the news: The latest estimates compiled by the Centers for Disease Control and Prevention show that the two variants — BA.4 and BA.5 — account for 21% of all new cases in the U.S. as of June 11. Per The Hill, this is a 15.5% increase from the last week of May.

  • However, BA.2.12.1, another omicron strain, still accounts for a majority of cases — 64% — in the U.S., per the CDC data.

What they’re saying: It’s unclear whether BA.4 and BA.5 will lead to a new wave of infections, hospitalizations and deaths, but trends suggest that the two variants will account for most U.S. cases, predicted Denis Nash, an epidemiologist at the CUNY Graduate School of Public Health & Health Policy, per The New York Times.

  • “This could happen very quickly,” Nash added.

Worth noting: These new subvariants have already created a surge of cases in South Africa, where most of the population has antibodies either through previous infection or vaccinations. But the death rate did not rise as sharply, the Times report noted.

The bigger picture: The European Centre for Disease Prevention and Control has already classified BA.4 and BA.5 as variants of concern, while the World Health Organization pointed to these strains as the cause of an increase in cases in more than 50 countries.

  • Per The Guardian, these two subtypes have spread in states including Texas, New Mexico, Arkansas, Oklahoma and Louisiana.
  • Currently, daily cases in the U.S. average at more than 100,000, with the number of daily average deaths at 276 and hospitalizations at more than 4,000.

State of play: Initial studies indicated that the newer variants especially have an ability to evade immunity from the vaccine, previous infection or both, as I previously reported for the Deseret News.

  • The latest Moderna booster may provide more protection against the omicron variants than the original shot the pharmaceutical company offered.
  • “We anticipate more durable protection against variants of concern with mRNA-1273.214, making it our lead candidate for a fall 2022 booster,” said Chief Executive Officer Stephane Bancel, per CNBC.

What to look out for: COVID-19 symptoms can appear from two to 14 days after exposure.

  • The symptoms for BA.4 and BA.5 are mostly mild, including fever, tiredness and a loss of smell.