Sisyphus was punished for cheating death twice by being forced to roll an immense boulder up a hill only for it to roll down every time it neared the top, repeating this action for eternity
French researchers tested how well antibodies produced by natural infection and by coronavirus vaccines neutralize the Alpha, Beta and Delta variants, as well as a reference variant similar to the original version of the virus.
The researchers looked at blood samples from 103 people who had been infected with the coronavirus. Delta was much less sensitive than Alpha to samples from unvaccinated people in this group, the study found.
One dose of vaccine significantly boosted the sensitivity, suggesting that people who have recovered from Covid-19 still need to be vaccinated to fend off some variants.
The team also analyzed samples from 59 people after they had received the first and second doses of the AstraZeneca or Pfizer-BioNTech vaccines.
Blood samples from just 10 percent of people immunized with one dose of the AstraZeneca or the Pfizer-BioNTech vaccines were able to neutralize the Delta and Beta variants in laboratory experiments. But a second dose boosted that number to 95 percent. There was no major difference in the levels of antibodies elicited by the two vaccines.
“A single dose of Pfizer or AstraZeneca was either poorly or not at all efficient against Beta and Delta variants,” the researchers concluded. Data from Israel and Britain broadly support this finding, although those studies suggest that one dose of vaccine is still enough to prevent hospitalization or death from the virus.
