Coronavirus: Across the world, over 4.3 crore have been affected by the virus.
UK Vaccine Taskforce Chair Kate Bingham said on Tuesday that the first generation of COVID-19 vaccines "is likely to be imperfect" and that they "might not work for everyone".
"However, we do not know that we will ever have a vaccine at all. It is important to guard against complacency and over-optimism", Bingham wrote in a piece published in The Lancet medical journal.
"The first generation of vaccines is likely to be imperfect, and we should be prepared that they might not prevent infection but rather reduce symptoms, and, even then, might not work for everyone or for long," she added.
Bingham wrote that the Vaccine Taskforce recognises that "many, and possibly all, of these vaccines could fail", adding the focus has been on vaccines that are expected to elicit immune responses in the population older than 65 years.
She said that the global manufacturing capacity for vaccines is vastly inadequate for the billions of doses that are needed and that the United Kingdom's manufacturing capability to date has been "equally scarce".
Earlier on Tuesday, a study by scientists at Imperial College London found that antibodies against the novel coronavirus declined rapidly in the British population during the summer, suggesting protection after infection may not be long lasting and raising the prospect of waning immunity in the community.
The Telegraph newspaper reported that the British government is working on the assumption that the second wave of coronavirus will be more deadly than the first.
(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)