New studies in France show new evidence that the most widely used vaccines against COVID-19 offer strong protection against the delta variant of the coronavirus, which is spreading rapidly around the world and is now the most prevalent in the United States.
The delta is increasing in populations with low vaccination rates. On Thursday, Dr. Rochelle Walensky, director of the US Centers for Disease Control and Prevention (CDC), said that is leading to “two truths”: Sections of the country with high immunization rates are returning to normality, while hospitalizations increase elsewhere.
“That rapid growth is worrying,” he said. A few weeks ago the delta variant accounted for just a quarter of new cases, but now it represents more than 50%, and in some places, such as parts of the center of the country, up to 80%.
Scientists at the Pasteur Institute in France on Thursday reported new evidence that full vaccination is key.
In laboratory tests, the blood of people who had received the first dose of the Pfizer or AstraZeneca vaccines “barely inhibited” the delta variant, the team reported in the journal Nature, but weeks after receiving the second dose, almost all had what the scientists consider an immune boost sufficient to neutralize that variant, although the protection was slightly less powerful than against previous versions of the virus.
French scientists also studied unvaccinated people who had survived COVID-19 and found that their antibodies were four times less potent against the new variant, but that a single dose of the vaccine greatly strengthened their immune response, unleashing overall protection against the delta variant and two other mutations, the study says. That supports the recommendation that COVID-19 survivors should be vaccinated rather than relying on their natural immunity.
Laboratory experiments add to real-life data indicating that the delta variant of the virus is not evading the most widely used vaccines in the Western world, but highlight that it is crucial that more people get vaccinated before the virus evolves further. .
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