22 Feb 2021
Public Health England (PHE) has today published the first independent analysis in the UK showing the Pfizer-BioNTech vaccine is effective from the first dose.
Early data from PHE’s SIREN study[i] show a promising impact on infection in healthcare workers aged under 65. Data show one dose reduces the risk of catching infection by more than 70%, rising to 85% after the second dose.
Healthcare workers in the study are tested for COVID-19 every 2 weeks – whether or not they have symptoms. This suggests the vaccine may also help to interrupt virus transmission, as you cannot spread the virus if you do not have infection.
PHE’s analysis of routine testing data also shows that one dose is 57% effective against symptomatic COVID-19 disease in those aged over 80. This effect occurs from about three to four weeks after the first dose.
Early data suggest the second dose in over 80s improves protection against symptomatic disease by a further 30%, to more than 85%.
Hospitalisation and deaths rates are falling in all age groups – but the oldest age groups are seeing the fastest decline since the peak in mid-January.
Early data suggest vaccinated people who go on to become infected are far less likely to die or be hospitalised. Overall, hospitalisation and death from COVID-19 will be reduced by over 75% in those who have received a dose of the Pfizer-BioNTech vaccine.
The risk of dying in those aged over 80 is less than half (56%) in vaccinated cases compared to unvaccinated cases, at least 14 days after receiving the first dose.
Those over 80 who develop COVID-19 infection after vaccination are around 40% less likely to be hospitalised than someone with infection who has not been vaccinated.
These high levels of protection are also seen against the variant of concern (B.1.1.7) first identified in South East England in December 2020.
While the data on infection, hospitalisation and death are promising, PHE will continue to observe these trends closely over the coming months to ensure firmer conclusions can be made.
PHE is also monitoring the real-world impact of the AstraZeneca vaccine and will publish these findings in due course – but early signals in the data suggest it is providing good levels of protection from the first dose.
Dr Mary Ramsay, Head of Immunisation at PHE, said:
“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.”
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.”
These data show clear protection from the first dose, particularly against severe disease, supporting the decision to maximise the number of people vaccinated with a single dose, as advised by the Joint Committee on Vaccination and Immunisation (JCVI).
The current dosing strategy will save more lives by ensuring more people receive protection from severe disease following the first dose.
There is also good evidence suggesting that giving the second dose of AstraZeneca later will lead to much higher levels of protection. Offering the booster at twelve weeks will therefore help to ensure longer lasting protection beyond the current restrictions.
[i] The SIREN (Sarscov2 Immunity & REinfection EvaluatioN) study involves a sample of healthcare workers undertaking symptom questionnaires, respiratory swabs and serum samples.
For further information please contact:
Public Health England Press Office
Tel: 020 7654 8400 Email: firstname.lastname@example.org Out of hours telephone 0208 200 4400
Vaccine effectiveness against symptomatic disease:
148,052 over-70s who reported symptoms and tested positive between 8 December 2020 and 12 February 2021 were included in the study.
By comparing how many of them were vaccinated when symptoms first appeared to how many were unvaccinated, we can estimate how effective the vaccine is at preventing symptomatic disease.
Hospitalisations – SARI-Watch
The Severe Acute Respiratory Infection (SARI) Watch surveillance system was established in 2020 to report the number of laboratory confirmed influenza and COVID19 cases admitted to hospital and critical care units (ICU/HDU) in NHS acute trusts across England.
The weekly rate of new admissions of COVID-19 cases is based on the trust catchment population of those NHS Trusts who made a new return. This may differ from other published figures such as the total number of people currently in hospital with COVID-19.
Hospitalisations - Emergency Care Data Set (ECDS)
PCR positive cases detected in pillar 2 testing are then linked to the Emergency Care Data Set (ECDS) to determine the proportion of the cases admitted to hospital. The ECDS is a national data set managed by NHS Digital and established to provide a more accurate, detailed and complete picture of all emergency attendances. Linking is undertaken on the basis of NHS number and date of birth.
Mortality in PCR positive cases is determined by linking on a daily basis to the Demographic Batch Service (DBS) to check NHS patient records for reports of individuals who died in the previous 24 hours in any setting.
The SIREN study is a PHE led cohort study of approximately 40,000 healthcare workers. Participants undertake symptom questionnaires and respiratory swabs every 2 weeks and a serum sample is taken every 4 weeks. Healthcare workers are one of the earliest groups to be offered the vaccine therefore this study is likely to provide one of the earliest estimates of vaccine effectiveness against infection.