US approves Covid-19 booster shot to counter declining vaccine efficacy
"We conclude that a booster shot will be needed to maximize vaccine-induced protection and prolong its durability"
The US on Wednesday authorised booster shots for all Americans from 20 September starting eight months after an individual has been fully vaccinated, warning that Covid-19 vaccination efficacy is decreasing over time.
"The available data make very clear that protection against (coronavirus) infection begins to decrease over time following the initial doses of vaccination, and in association with the dominance of the Delta variant we are starting to see evidence of reduced protection against mild and moderate disease," the nation's top health officials said in a statement, reports the NDTV citing Agence France-Presse.
"We conclude that a booster shot will be needed to maximize vaccine-induced protection and prolong its durability."