The government's health agency said on Friday that both Pfizer and AstraZeneca Covid-19 vaccines were effective against symptomatic Covid-19 infection in high risk groups, citing a preprint study based on one million vulnerable people.
Overall vaccine effectiveness against symptomatic disease in risk groups was around 60 per cent after one dose of either AstraZeneca or Pfizer-BioNTech with little difference by age, Public Health England (PHE) said.
That rises to 81 per cent for AstraZeneca following a second dose in people in risk groups aged 16 to 64, with no data available for Pfizer. Among those over 64, Pfizer was 89 per cent effective and AstraZeneca 80 per cent effective after the second dose, the health agency said.
"This real-world data shows for the first time that most people who are clinically vulnerable to Covid-19 still receive high levels of protection after 2 doses of vaccine," said Mary Ramsay, head of Immunisation at PHE.
“It is vital that anyone with an underlying condition gets both doses, especially people with weakened immune systems as they gain so much more benefit from the second dose.”
The finding is based on a study involving more than a million people in at-risk groups.
The Joint Committee on Vaccination and Immunisation (JCVI) advised that those living with immunosuppressed adults should be prioritised for vaccination to help limit the spread of the virus to people in this group.
If the planned booster programme goes ahead, the JCVI has recommended that immunosuppressed adults and their household contacts should also be among the first to be offered a third dose of vaccine in September.
In rare cases, listeria can lead to serious complications such as meningitis and sepsis.Getty Images 
