SIREN study shows encouraging results

Single dose of Pfizer-BioNtech vaccine provides high levels of protection against COVID-19 infection

Coronavirus vaccine

Early data from Public Health England (PHE)’s SIREN study, involving healthcare workers under 65, has revealed a single dose of Pfizer-BioNtech’s COVID-19 vaccine reduces their risk of catching COVID-19 by 70%, rising to 85% after the second dose. Importantly, these high levels of protection are also seen against the now-predominant ‘Kent variant’ of COVID-19 which was first identified in December 2020.

Previous results from this study revealed that past infection with COVID-19 provided over 80% protection from repeat infection for at least five months. With the Pfizer-BioNtech COVID-19 vaccine now being made available to healthcare workers, SIREN researchers have been able to analyse the effects of the vaccine on COVID-19 infection.

PHE will continue to monitor the impact of the vaccine on COVID-19 infection over the coming months in order to strengthen this conclusion, however these encouraging results highlight the importance of vaccines in controlling the spread of COVID-19 and support the current vaccination strategy being rolled out across the UK.

The SIREN study was launched in May 2020 with the key aim of regularly testing patient-facing healthcare workers for the presence of the COVID-19 virus and COVID-19 antibodies in order to determine whether pre-exposure to the virus confers protective immunity. At the Trust, the SIREN study team recruited 448 staff from Princess Royal University Hospital (PRUH) and King’s College Hospital, as well as an additional 50 from the South London and Maudsley Hospital.

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.”

Read the full press release.