New research underscores that current COVID vaccines protect against Delta variant

New research from France adds to the evidence that widely-used COVID-19 vaccines still offer strong protection against a coronavirus mutation that is spreading rapidly around the world and is now the most prevalent variant in the US.

The Delta variant is surging through populations with low vaccination rates, says Dr. Rochelle Walensky, director of the US Centers for Disease Control and Prevention.

This, she says, is leading to “two truths” — highly-immunized swaths of America are getting back to normal, while hospitalizations are rising in other places. “This rapid rise is troubling,” Walensky says.

A few weeks ago, the Delta variant accounted for just over a quarter of new US cases, but it now accounts for just over 50% — and in some places, such as parts of the Midwest, as much as 80%.

Researchers from France’s Pasteur Institute reported new evidence today that full vaccination is critical.

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

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

The French researchers also tested unvaccinated people who had survived a bout of the coronavirus, and find that their antibodies were four-fold less potent against the new mutant.

But a single vaccine dose dramatically boosted their antibody levels — sparking cross-protection against the Delta variant and two other mutants, the study finds. That supports public health recommendations that COVID-19 survivors get vaccinated rather than relying on natural immunity.

The lab experiments add to real-world data that the Delta variant’s mutations aren’t evading the vaccines most widely used in Western countries, but underscore that it’s crucial to get more of the world immunized before the virus evolves even further.

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