But omicron has mutated so quickly that several new subvariants have emerged since then that are even better at evading the immune’s system’s defenses. Two of those, known as BA. 4 and BA. 5, are now responsible for 13 percent of new coronavirus cases in the United States, the Centers for Disease Control and Prevention said in new estimates. It is unclear whether BA. 4 and BA. 5 will become dominant in the coming months, or whether existing immunity in the population from infection and vaccinations will curb their spread.
Biden administration officials have said they are preparing for a fall and winter wave that could see 100 million coronavirus infections and a potentially significant wave of deaths, driven by omicron subvariants. That makes it even more critical that more effective vaccines are available, particularly to protect the elderly and most vulnerable.
Moderna executives said on a call Wednesday they were confident the updated vaccine would still provide additional protection against newer omicron subvariants, even though researchers tested its booster dose against BA.1. Even if the updated booster provides less protection against later omicron subvariants than against BA. 1, it will likely still be more effective against them than the company’s existing booster, said Moderna President Stephen Hoge.
“We’re pretty confident this vaccine is going to provide a benefit even against the family of omicron subvariants,” Hoge said on a briefing call with reporters.
Soon after omicron was identified in southern Africa late last year, Moderna said it was developing shots specifically designed to fight the variant. Pfizer and BioNTech announced the same plan, though they have not yet released data on their updated vaccine.
Data from the recent clinical trial, which involved 437 participants, showed that Moderna’s omicron-targeting booster would probably provide longer protection against variants a month afterward when compared with earlier versions of its coronavirus vaccine, Moderna said.
The booster “was generally well-tolerated,” with side effects comparable to earlier boosters, the company said.
The White House for several months has pressed Congress for more than $20 billion for the coronavirus response. Lawmakers have yet to approve new funding.
The official count of new daily coronavirus infections is slowly climbing in the United States, although the actual numbers are believed to be far higher since so many people are testing themselves at home. The country recorded a 38 percent uptick in new cases during the past week, according to figures compiled by The Washington Post, as protection from booster shots and previous infections wanes and more people go about their lives without masks.
Globally, new coronavirus cases are still declining after the omicron variant triggered tens of millions of new cases worldwide, driving up infections to peaks during the winter.