People who were infected with an earlier version of the coronavirus and received three doses of an mRNA vaccine, such as the Pfizer/BioNTech shot, appear to be best protected against symptomatic infection by the Omicron variant, according to a large study.
People infected with the earliest version of the Omicron variant of the coronavirus, first identified in South Africa in November, may be vulnerable to reinfection with later versions of Omicron even if they have been vaccinated and boosted, new findings suggest.
The subvariants appear to be escaping immunity from vaccines and previous infections even other Omicron infections and have been causing hundreds of thousands of new COVID-19 cases in recent weeks.
The two newest subvariants of Omicron, BA.4 and BA.5, are spreading across the US and making up a higher percentage of new cases, prompting concerns about increased transmissibility.
Moderna releases data from a trial that evaluates the efficacy, safety, and tolerability of a new booster containing a vaccine that specifically targets the Omicron variant.