MUMBAI: India has decided to keep the 28-day interval between two doses of Covidshield vaccine, but there is growing evidence that a longer interval – almost three months – would be better. In a study published in the medical journal The Lancet, researchers at Oxford University (where Covishield was developed) said an interval of three months between the doses of the vaccine results in a greater effectiveness of the vaccine, instead of a six-week interval.
The first dose of the vaccine offers 76% protection for up to three months, says the study. Many doctors in India have also raised the theory of “better antibody levels with a longer range” with the government.
We believe that there should be a two-month gap between the two vaccines, ”said Dr. Shashank Joshi, who is a member of the Maharashtra Covid task force. The other important message in the new Lancet study is that a longer interval would allow countries to vaccinate a larger proportion of their population more quickly.
In a statement, the study’s lead author, Andrew Pollard, of the Oxford University said: “Where there is a limited supply, policies to initially vaccinate more people with a single dose may provide greater immediate protection for the population than vaccinating half the number of people with two doses.”
The team also found that a single dose of the vaccine is highly effective in the first three months (76% effective from 22 days after vaccination). “Levels of antibodies against the SARS-CoV-2 spike protein remained at similar levels for 3 months,” said the Lancet study.
