More than two years into the COVID pandemic, it seems as though almost everyone has been infected with the coronavirus by now. In fact, if you haven’t gotten COVID yet, you likely feel like one of the rare few. By Feb. 2022, 60 percent of all Americans had been infected with the coronavirus at least once, according to the Centers for Disease Control and Prevention (CDC), and a majority of these infections were caused by the Omicron variant, which started spreading in the U.S. last winter. This variant caused a record number of COVID cases in the country from November through January before infections started steadily falling in February.
New cases are no longer declining, however. Last month, we started to see infections increasing once again, largely thanks to a subvariant of the Omicron variant, BA.2. According to the latest data from the CDC, the U.S. has seen COVID cases increase by more than 21 percent in just the last week alone.
BA.2, otherwise known as “stealth Omicron,” quickly became the country’s dominant coronavirus variant in late March, but other Omicron subvariants have been popping up across the world. Now, there are at least four mutated versions of the original Omicron variant circulating around the U.S., according to New York Magazine: BA.2, BA.2.12.1, BA.4, and BA.5.
And while BA.2 is still the dominant variant circulating, cases of BA.2.12.1 are increasing significantly. The CDC is reporting that this subvariant is now responsible for 42 percent of cases in the country—a substantial jump up from 22 percent just two weeks ago. This is a large concern for virus experts, who say that BA.2.12.1 is even more transmissible than Omicron or BA.2.
“With the emergence of Omicron (BA.1) in late 2021, we saw a hyper-transmissible variant unlike any previous ones with an estimated three-fold increase in its effective reproduction number compared with Delta,” Eric Topol, MD, a public health expert and founder of the Scripps Research Translational Institute, explained in a May 4 blog post. “That evolution has proceeded full steam with BA.2 that has a 30 percent increased transmissibility, and now, in the United States, about to become dominant, BA.2.12.1, which has yet another 25 percent increase in transmissibility.”
Unfortunately, this “increased infectiousness of the virus” is not just a concern for the small percentage of people who have not had COVID yet. In April, a preprinted study posted on medRxiv found that it was relatively rare for those who had been infected the original BA.1 Omicron variant to get reinfected with the BA.2 subvariant. But according to Topol, this is likely not the case with the soon-to-be-dominant BA.2.12.1 subvariant, which has been found to have “reduced cross-immunity” to the BA.1 variant.
This means if you were infected with the virus during Omicron’s record-breaking reign in the winter, you “may be susceptible to reinfections” by this new subvariant, according to Topol. The public health expert said it is estimated that 40 percent of Americans who have been infected with COVID were infected with the original Omicron variant. “Many people with Omicron infections will get reinfections by BA.2.12.1, especially if they remain unvaccinated,” Topol tweeted on May 10.
This could also spell trouble for one of the main vaccine development strategies currently underway in the U.S. “The Omicron-specific vaccines that use the BA.1 spike structure, which are in clinical trials and due to read out in the next couple of months, may not fulfill their promise with a variant that carries such immune escape properties,” Topol explained in his blog post.