By Michelle Roberts
Health editor, BBC News online
Covid vaccines are highly effectual successful radical with underlying wellness conditions who were advised to shield earlier successful the pandemic, real-world UK information reveals.
The study of much than a cardinal radical successful at-risk groups shows 2 doses of the Pfizer oregon AstraZeneca vaccines are needed for this protection.
Being double-jabbed reduced the hazard of symptomatic Covid-19 by astir 90%.
One dose chopped it by astir 60%, says Public Health England (PHE).
It takes a mates of weeks for the extortion offered by a 2nd to footwear in.
Protection against hospitalisation and decease successful at-risk groups is expected to beryllium greater than extortion against symptomatic disease, arsenic has been seen successful studies of the wide population, though much information is needed to corroborate this.
The survey findings besides screen a clip play erstwhile the Alpha, oregon UK, coronavirus variant was dominant, alternatively than the Delta one, which is down astir infections occurring now.
But experts are progressively assured that existing vaccines inactive enactment good against Delta.
Dr Mary Ramsay, caput of immunisation astatine PHE, said: "This real-world information shows for the archetypal clip that astir radical who are clinically susceptible to Covid-19 inactive person precocious levels of extortion aft 2 doses of vaccine.
"It is captious that anyone with an underlying information gets some doses, particularly radical with weakened immune systems arsenic they summation truthful overmuch much payment from the 2nd dose."
In the study, 1 dose of vaccine was, connected average, lone 4% effectual successful radical with weakened immune systems. Efficacy accrued to 74%, however, aft 2 doses.