A single dose of the Pfizer vaccine provides “very high” protection from Covid-19 after 21 days – without a ‘top up’ dose in the recommended time frame, according to a new study from the University of East Anglia.
Researchers looked at data from Israel, where the vaccine has been rolled out.
They found that the Pfizer vaccine becomes 90 per cent effective after 21 days – supporting UK plans to delay the timing of a second injection.
But they warn that people’s risk of infection doubled in the first eight days after vaccination – possibly because people become less cautious.
