Pollard said that initially vaccinating more and more people with the single-dose may help governments vaccinate a greater share of the population in the short run.
Canada has not yet approved the AstraZeneca-Oxford shot, but is set to receive millions of doses if it is authorized by Health Canada.
Pakistan this month started the anti-coronavirus vaccination drive with 500,000 doses of Sinopharm's vaccine donated by its ally China.
The primary outcome of the trial was the number of symptomatic Covid-19 cases (confirmed by positive Covid-19 test, and having fever, cough, shortness of breath, loss of smell or loss of taste) in the control and Covid-19 vaccine groups occurring more than 14 days after the second dose. 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.
According to the scientists, participants who were given their doses 12 or more weeks apart had greater protection than people given their two doses less than six weeks apart.
"The big problem that is coming up is the mRNA is able to retain a lot of their effectiveness with the variants, AstraZenecas' vaccine may not perform as well with variants and that seems to be the thing that is really holding things up".
Switzerland earlier this month demanded more efficacy and quality data before greenlighting the shot that has already been approved by the European Union.
Modelling analysis indicated that this protection did not reduce over the three months, they added.
Kelly Grindrod a professor in pharmacy at the University of Waterloo said mRNA vaccines such as Pfizer and Moderna are different than AstraZeneca, which is a viral vector. The study also found that the level of antibodies against the SARS-CoV-2 also remained the same throughout the period of three months.
However, the study authors mentioned that they were not sure if the single dose of the vaccine would extend its protective shield for a period of more than three months as the study was conducted with a time period of up to three months only.
She believes the findings further support the relationship between vaccine interval and efficacy in those receiving two standard doses.