Professor Jonathan Van-Tam, England's deputy chief medical officer, said on Jan. 24 that “we do not yet know the impact of the vaccine on transmission of the virus.”
Therefore, he urged the millions of Britons who have already been vaccinated to keep following the lockdown rules.
“If you change your behaviour you could still be spreading the virus, keeping the number of cases high and putting others at risk who also need their vaccine but are further down the queue.”
Health Secretary Matt Hancock said on Sunday that Van-Tam “is right”.
Van-Tam also warned that “no vaccine has ever been 100 percent effective” and “no-one will have 100 percent protection from the virus.”
Van-Tam said that the immune response is “only fully trained up around two or three weeks after you have each of your two jabs.”
“If you are older it’s better to allow at least three weeks. You can still get COVID-19 in this time.”
He added that “the way to reduce everyone’s risk is to break the chains of transmission and really push down the number of cases.”
He further warned that there are still "very high" numbers of hospital admissions and deaths, with a quarter of people hospitalised under the age of 55.
By Saturday, 5,861,351 people had received the first dose of a COVID-19 vaccine in the UK, the government said.
Public Health England reported on Saturday that there were 33,552 new CCP virus cases across the UK and 1,348 deaths within 28 days of a positive test.