The authors note this regimen may be beneficial while vaccine supplies are initially limited.
Addressing a press conference in Islamabad, he said that Pakistan will receive 2.8 million doses of AstraZeneca's coronavirus vaccine on March 2 as the first batch of a donation from the worldwide COVAX programme.
Some other vaccines, such as for flu, Ebola and malaria, also provide greater protection and stronger immune responses after a longer interval between doses.
Mexico " s Health Department reported 1,075 newly confirmed COVID-19 deaths Wednesday, bringing the total death toll to 177,061.
It said that the period where workers remained at risk of becoming infected with Covid-19 would be lengthened until May or June of 2021 "as the gap for the AstraZeneca first and second dose is longer than the timeframe for the Pfizer Biontec 21-28 days". They are being given the Chinese-made Sinopharm vaccine, which is a two-dose vaccine with an efficacy of 78.6%. In addition, antibody levels against the SARS-CoV-2 spike protein remained at similar levels for 3 months.
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. 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. For this reason, a second dose of vaccine is still recommended.
Professor Neil Ferguson, from Imperial College London, said the data on vaccine effectiveness and how quickly infection, deaths and hospital cases were declining across the country was looking promising. Real-world assessments of how the vaccine is working in the population will be needed to confirm this preliminary result.