Rates of hospitalisation and death from Covid-19 are reduced by 75% from a single dose of the Pfizer-BioNTech vaccine, landmark new data has revealed.
The first major real-world analysis of vaccine efficacy by Public Health England found the jabs provide a high level of protection against infection and symptoms from the first dose – including against the Kent variant.
Early data from PHE’s SIREN study, which monitors vaccinated healthcare workers under 65, shows one dose reduces the risk of infection by more than 70%, rising to 85% after the second dose.
While PHE’s analysis of routine testing data also shows that one dose is 57% effective against symptomatic COVID-19 disease in over 80s from about three to four weeks after the first dose.
This would rise by around 30% after a second dose, bringing protection against symptomatic cases to more than 85% for over 80s.
Scientists claim the findings help validate the policy to delay second doses to allow more people to be jabbed faster.
Dr Mary Ramsay, head of immunisation at PHE, said: “What we are beginning to see is that there’s evidence from one dose of vaccine reducing the rate of symptomatic cases in older people, starting at around three weeks after the date of vaccination.
As you will be aware most of our cases are the so-called Kent variant, so the vaccine is protecting against that variant.
“The good news is that on top of that reduction in symptomatic cases, the vaccine protection against severe disease from a single dose is even higher – at least 75%.
And I think that does reinforce the policy of giving that single dose to more people to prevent more deaths and more admissions now, and then go back later and give a second dose which will give them longer lasting protection and give them better protection – particularly against those milder forms of the disease.”
She added that it was too early to share data on the AstraZeneca vaccine, but said it was also “showing signs of a good effect”.
The SIREN findings also suggest the Pfizer jab could help to interrupt virus transmission, however scientists stressed more information is needed.
Dr Ramsay added: “This is strong evidence that the Pfizer-BioNTech vaccine is stopping people from getting infected, while also protecting cases against hospitalisation and death.
“We will see much more data over the coming weeks and months but we should be very encouraged by these initial findings.
“But protection is not complete, and we don’t yet know how much these vaccines will reduce the risk of you passing COVID-19 onto others.
“So even if you have been vaccinated, it is really important that you continue to act like you have the virus, practice good hand hygiene and stay at home.”
And the government’s chief scientific advisor, Sir Patrick Vallance, said the data does not mean lockdown can be eased any quicker, warning that even high levels of protection and vaccine uptake would leave large numbers of people unprotected.
Health Secretary Matt Hancock said: “This crucial report shows vaccines are working – it is extremely encouraging to see evidence that the Pfizer vaccine offers a high degree of protection against coronavirus.
“Vaccines save lives, and so it is vital we roll out the vaccine programme as fast as possible, and that as many people as possible take the jab. This new evidence shows that the jab protects you, and protects those around you.
“It is important that we see as much evidence as possible on the vaccine’s impact on protection and on transmission, and we will continue to publish evidence as we gather it.
“As we roll out the jab, it is vital people continue to play their role in protecting the NHS by sticking with the rules.”