One dose of Pfizer or AstraZeneca, or two? Studies reveal


The first studies of the comprehensive vaccination program in Britain showed strong evidence that coronavirus vaccines were working as intended, working to reduce the rate of hospitalization, and possibly reducing virus transmission, according to the New York Times..

British studies have found that a single dose of the Oxford – AstraZeneca or Pfizer vaccine can reduce most cases of symptoms associated with the Coronavirus, and separate studies have provided new evidence that a single dose of the Pfizer vaccine may reduce the spread of the virus.

These results were reinforced by studies conducted in Israel, which reported that the vaccine developed by Pfizer and Betonic provided significant protection from the virus in real-world conditions and not only in clinical trials conducted last year..

The study also showed that the two vaccines were effective against the most contagious Corona virus variant that had spread in Britain and spread throughout the world..

“They both work very well,” said Aziz Sheikh, a professor at the University of Edinburgh who helped conduct the Scottish vaccine study.“.

While British lawmakers have indicated the power of vaccines in announcing a gradual easing of lockdown restrictions, government scientists have warned that many people need injections to prevent an outbreak of the epidemic among vulnerable groups, who may suffer serious symptoms or death..

One dose

Britain also decided to postpone giving people second doses of the Pfizer and AstraZeneca vaccine for up to three months after the first doses, and it chose to provide partial protection for more people from a single dose..

Arne Akbar, a professor at University College London and president of the British Society for Immunology, said: “We now need to understand how long this protection lasts for one dose of vaccine.“.

One new study in about 19,000 health workers in England who received the Pfizer vaccine revealed that a single dose of the vaccine reduced the risk of infection by nearly 70 percent. Scientists said that after two doses of the vaccine, protection had risen to 85 percent.

The Pfizer vaccine has also been shown to be effective in older adults, who are not well represented in clinical trials and do not always have strong responses to vaccines..

But British studies were unable to determine how long high levels of protection would last from a single dose of Pfizer or AstraZeneca..

In the Scottish study, protection began to decline four to five weeks after receiving the initial dose. Simon Clark, a professor of cellular microbiology at the University of Reading, who was not involved in the study, said: “The maximum protection is four weeks, then it starts to decline“.


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