The Omicron subvariants known as BA.4 and BA.5 now represent 13 percent of new coronavirus cases in the United States, up from 7.5 percent a week ago and 1 percent in early May, according to the latest estimates by the CDC.
The two sublineages, which were added to the World Health Organization’s monitoring list in March and designated as variants of concern by the European Centre for Disease Prevention and Control (ECDC), were present in all U.S. regions.
The CDC notes that SARS-CoV-2, the virus that causes COVID-19, is constantly changing and accumulating mutations in its genetic code over time. New variants will continue to emerge, while some variants will disappear and others will emerge and continue to spread.
However, according to the New York Times, the spread of the two subvariants does add more uncertainty to the trajectory of the pandemic where current case counts are likely to be undercounted.
Scientists are still unclear as to whether this will lead to a major new wave of infections, or spikes in hospitalizations and deaths.
Subvariants are able to dodge antibodies
Last month, scientists in South Africa found that the sublineages of the Omicron coronavirus variant can dodge antibodies from earlier infections well enough to trigger a new wave, reports Reuters.
According to the CDC’s estimates, BA.4 made up 5.4 percent of the variants in the country for the week ending June 4, while BA.5 made up 7.6% percent of the variants during the same time.
The seven-day moving average of U.S. COVID-19 cases stood at 98,010 as of June. The 4.BA.4 and BA.5 subvariants will likely be dominant in the U.S. by the end of the summer or early fall, White House Covid-19 coordinator Dr. Ashish Jha told NBC News.
The “very rapid viral evolution” of the omicron strain of the virus is the result of the pathogen trying to find its way around the “wall of immunity” in the U.S., Jha said.
Because a substantial amount of Americans have some form of immunity to the virus — either from vaccination, prior infection, or both — the only way the virus can survive is to mutate into forms that can evade this immunity.