Public health experts have largely offered up reassurance that existing COVID-19 vaccines work well against dominant variants, as NPR reported Friday.
However, a small real-world study by Israel's Tel Aviv University, released Saturday, suggests that the B.1.351 variant first discovered in South Africa may be able to evade the Pfizer vaccine, Reuters reports.
There were 8X as many cases involving the variant among 400 patients who’d received 2 doses of the Pfizer vaccine 14+ days before compared to 400 unvaccinated patients.
Caveat: This small preprint study only included those who’d already tested positive for COVID-19; also, the South Africa strain is far from dominant in Israel.
In the US, a small fraction of the 66 million fully-vaccinated Americans have experienced “breakthrough infections;” some have required hospitalization, The Washington Post reports.
These infections—which likely number in the thousands—are extremely rare but are being closely watched by officials.
Most Likely Reason: Top officials say individual patients probably mounted a weak immune response to the vaccine—noting that fully-vaccinated individuals who died were older people who likely had underlying conditions. It’s rare for breakthrough infections to result in severe illness.
But: While there’s no conclusive evidence that variants are driving breakthrough infections, major gaps in US virus sequencing data make it impossible to identify the strain behind every case.
Reminder: Some breakthrough cases are to be expected, says NIH chief Francis S. Collins. “These are still vaccines that are fantastically safe and effective. But 95 percent is not 100 percent.”
More vaccine news:
China—whose vaccines lag behind global competitors in terms of efficacy, but are easier to store—is considering mixing formulas or adding doses to boost their effectiveness, AP reports.
China’s current roster of 5 vaccines are said to range from 50% to 79% efficacy.