But expert says it still gives ‘good protection’ against COVID
MANILA – The efficacy of the Pfizer and AstraZeneca vaccines against COVID-19 wane under the Delta variant, but two full doses of these vaccines still provide good protection against new infections, a study from the University of Oxford showed.
“We do see that protection isn’t quite as good as it was against Alpha, but two doses in particular either Pfizer or AstraZeneca are still giving really good protection against new infections with Delta, but getting that second dose is really important,” said Sarah Walker, professor of medical statistics and epidemiology.
“The other thing is we also see that even if you’ve had COVID before, you still do better with two vaccine doses. So having two vaccinations even if you’ve had COVID reduces your risk of new infection even further,” she added.
The study tracked around 400,000 people in the UK and tested them for COVID-19 every month, regardless of whether or not they had symptoms or had been vaccinated.
Walker said the study’s results show no immediate cause for concern, and it remains to be seen if boosters for the general population are needed in the near future.
“The point about boosters is to stop people ending up in hospitals or dying. And we just don’t know that yet.”
“Obviously there’s a lot of people who haven’t even had a first vaccination. And so you know the idea of giving boosters to people who you know, maybe don’t need it quite yet is obviously challenging for the healthcare system,” she added.
Walker said the study suggests that the Pfizer and AstraZeneca vaccines may be “doing something quite different against COVID.”
“And so more research is definitely needed into strategies that maybe mix-and-match, so instead of having two of the same dose, maybe you have one and maybe one of the other,” she explained.
Walker said that if vaccines are working differently in different people, experts may need to think about different kind of booster strategies depending on what vaccine people have first.
Nonetheless, she stressed that being vaccinated is still the surest way of protecting oneself against COVID-19.