Among older adults who received the Pfizer–BioNTech vaccine, Israel has seen 94% protection from SARS-CoV-2 infection in people over 85 years old
3. This is remarkably high for that age group, and considerably higher than Moustsen-Helms’s result of 64%, possibly in part because
long-term-care residents are prone to be in poor health. Similarly, a UK study found that the Pfizer–BioNTech and Oxford–AstraZeneca vaccines were both 80% effective at preventing COVID-19 hospitalizations in people aged 70 or older
5. Studies are under way to see whether vaccine effectiveness can be boosted even more by
mixing and matching vaccines, and
early results have been promising. But the vaccines have already exceeded expectations, says Meissner, especially given how quickly they were developed — despite thorough safety testing in unusually large clinical trials — and the novel approaches they used. Some vaccines spend years in development, and still might not achieve this level of protection. “The efficacy of these vaccines is absolutely remarkable,” says Meissner.