Two-dose COVID-19 vaccine response works against delta variant, researchers find

New data out of France adds to evidence that widely used COVID-19 vaccines still offer strong protection against the Delta variant, which is spreading around the world and is now the most prevalent strain in the US, as reported by CBC News.

However, researchers from the Pasteur Institute reported that full vaccination is critical.

In laboratory tests, blood from several dozen people given their first dose of the Pfizer/BioNtech or AstraZeneca vaccines "barely inhibited" the Delta variant, the team reported in the journal Nature.

But weeks after getting their second dose, nearly all had what researchers deemed an immune boost strong enough to neutralize the strain, even if it was a little less potent than against earlier versions of the virus.

The researchers also tested unvaccinated people previously infected with the coronavirus, and found their antibodies were four-fold less potent against the new mutant.

A single vaccine dose, however, dramatically boosted their antibody levels, sparking cross-protection against the delta variant and two other mutants, the study found.