Half of each dose targets the original virus, while the other half targets the omicron variant. The vaccine was effective against both, as well as the omicron sub-variants BA.4 and BA.5, in clinical trials, the agency said.
Though new coronavirus infections have subsided from the peaks of last winter, the World Health Organization has been reporting millions of fresh cases every week this summer, partly from the spread of omicron’s subvariants and also from waning immunity from previous infections or vaccine shots. Health officials are also preparing for a potential surge in cases this fall and winter.
In the United States, the Biden administration has been crafting a coronavirus booster campaign for launch in September with an updated vaccine designed to provide stronger protection against the omicron subvariants. The Food and Drug Administration has received assurances from Moderna and fellow vaccine-makers Pfizer and BioNTech that reformulated doses will be ready in September.
About two-thirds of the United States’ approximately 330 million residents have been fully vaccinated, according to figures compiled by The Washington Post. In the past seven days, 226 new infections have occurred for every 100,000 people, a decline of 3 percent from the previous week, though lower testing rates and reliance on at-home tests have made it more difficult to track cases.
The Centers for Disease Control and Prevention relaxed guidelines aimed at limiting the spread of the coronavirus last week, indicating that the Biden administration had decided that the lower covid-19 fatality rate in a heavily vaccinated population allowed it to adopt less rigid preventive measures.
The CDC, though, still recommends a first booster dose to everyone ages 5 and older. A second booster is recommended for those 50 or older and immunocompromised people 12 or older.
In Britain, about three-quarters of the country’s 67 million people have been fully vaccinated. In the past week, its infection rate declined by about 20 percent, with about 80 infections for every 100,000 residents.