Two new strains of COVID that appear to be more transmissible than even “stealth Omicron,” and that have the ability to evade antibodies from vaccination and prior infection, have arrived in the U.S.—and they could mean a new wave is coming.
BA.4 and BA.5—like the original Omicron, BA.1—originated in South Africa. Cases are surging there despite the fact that almost all South Africans have been vaccinated or had COVID, Bloomberg reported last week. The country's National Institute for Communicable Diseases reported nearly 4,000 new infections on Sunday alone. Of those who were tested for COVID, 22% received positive results. The World Health Organization initially recommended levels of below 5% for communities wishing to reopen after COVID's first wave.
People who have been both vaccinated against COVID and infected with Omicron may very well get sick if they contract the subvariants. But they probably won’t require hospitalization or die, a top COVID researcher from South Africa told Fortune.
“If you were vaccinated and had Omicron, your protection is decent, at least against severe disease,” said Alex Sigal, a professor at the Africa Health Research Institute in South Africa. He’s one of the authors on a new study that found BA.4 and BA.5 could result in a new wave of infection due to their ability to evade antibodies, both from vaccination and earlier infection.
“If anybody is protected, it should be these people,” he added.
That’s good news for many, but America’s vaccination rates are not where they could be. Around 66.2% of the total population is fully vaccinated, and only 45.8% have received a booster, according to the CDC. Children under 5 are still not eligible for the vaccine.
Others won’t be so fortunate. Sigal says those who have been infected with COVID prior to Omicron likely don’t have much immunity to BA.4 and BA.5. Those who were infected with Omicron but not vaccinated won’t have much immunity either. “It could go either way” for them, he said.
BA.4 and BA.5 appear to be more infectious than BA.2, also known as “stealth Omicron,” which was more infectious than the original Omicron, Bloomberg reported Thursday, citing South African COVID expert Tulio de Oliveira, the head of the institutes at the universities of KwaZulu-Natal and Stellenbosch.
On Friday, Fortune was the first to report that both variants had arrived in the U.S., citing multiple COVID-19 researchers with access to Gisaid, an international research database that tracks changes in COVID and the flu virus. The earliest sample of BA.4 in the U.S. was collected on March 30. The earliest sample of BA.5 in the U.S. was collected March 29.