Pakistan this month started the anti-coronavirus vaccination drive with 500,000 doses of Sinopharm's vaccine donated by its ally China. While specific transmission studies were not included in our analysis, United Kingdom trial participants were tested for Covid-19 each week regardless of symptoms, and we combined this with other positive Covid-19 cases in the trial to help determine the overall impact of the vaccine on risk of infection.
This compares to 55% protection when the second doses were given after a six-week interval.
The UK policy of leaving up to 12 weeks between doses also resulted in a higher efficacy overall, the study found.
The Department of Health is not expecting the 5,700 first doses and 3,700 second doses of Moderna vaccine to Wyoming locations this week due to the weather problems in other states.
State health officials say the bad weather is slowing the delivery of COVID-19 vaccines to Nebraska.
Scientists are urging people to have two doses of the vaccine to increase its protection levels.
"All those things matter, and those are things that we have to do better at", he told the BBC.
NIAC has said the AstraZeneca vaccine will only be administered to adults under the age of 70 in the State, despite the World Health Organization recommending it for all adults over 18, due to a lack of data regarding its efficacy among older people.
Professor Pollard said: "It is important to understand whether vaccines can reduce Covid-19 transmission".
"And it still may well be that by the end of May, we're in a very different country than we are today".
Last month, AstraZeneca agreed to supply nine million additional doses of its vaccine to the European Union following a row over the bloc's vaccination programme.
The authors note this regimen may be beneficial while vaccine supplies are initially limited.