Booster shots with messenger RNA vaccines such as those made by Pfizer Inc. and BioNTech SE failed to block omicron in a study of some of the first documented breakthrough cases caused by the highly contagious variant.
Seven German visitors to Cape Town experienced symptomatic COVID-19 infections between late November and early December despite being boosted, the researchers, whose investigation was authorized by the University of Cape Town and Stellenbosch University, said in findings published Tuesday in The Lancet. All the cases were mild or moderate, providing support for the extra shots’ ability to fend off severe disease, death and hospitalizations.
Still, the findings demonstrate omicron’s ability to evade immunity generated by even the most powerful COVID-19 vaccine boosters. That underscores the need to continue fighting the pandemic with measures besides vaccination, such as social distancing and masking, the authors said.
