The amount of protection provided by AstraZeneca's COVID-19 vaccine starts declining three months following the second dose, according to the latest study published in leading medical journal The Lancet on Tuesday.

"Vaccines have been a key tool in fighting the pandemic, but waning in their effectiveness has been a concern for a while. By identifying when waning first starts to occur, it should be possible for governments to design booster programs that can ensure maximum protection is maintained," noted Aziz Sheikh, a professor at the University of Edinburgh.

The study was conducted using the data based on two million vaccinated people in Scotland and an additional 42 million people in Brazil.