A new study led by Universities of Sheffield and Oxford shows that one dose of Pfizer’s Covid-19 vaccine generates robust T cell and antibody responses in 99 per cent of people.
The Protective Immunity from T cells to Covid-19 in health workers study (PITCH) examined how the immune system responds to Covid-19 after one dose of the Pfizer vaccine among people who have been infected by Covid-19 before and those who have not.
It suggests one dose of the vaccine protects against severe disease, supporting the decision to delay the second dose and provide protection to as many higher-risk groups as possible by providing more first doses.
The study showed after two doses levels of protection were even stronger, underlining the importance of people coming forward for their second dose.
The study also sheds light on the impact of previous infection from Covid-19 on people’s immune response to vaccination. It found people who had previously been infected with Covid-19 showed higher T cell and antibody responses after one dose of the Pfizer vaccine compared with people who had never had Covid-19 before and had one dose of the vaccine.
The researchers discovered that among people who had had Covid-19 in the past, the T cell response expanded after vaccination to recognise more regions of the Covid-19 spike protein-which attacks the immune system and causes severe disease.
This means, even in those already infected, vaccination from the Pfizer jab provides better protection and an enhanced immune response to Covid-19 than the immune response from natural infection.
Health secretary Matt Hancock said: “The PITCH study presents further proof that vaccines provide excellent protection against the virus. Thanks to the incredible efforts of our vaccination programme, over half of all adults in the UK have had the jab, and we remain on track to offer all adults a vaccine by the end of July.
“A second vaccine jab is crucial for longer-term protection, regardless of whether you have previously had Covid-19 or not, and I urge everyone to make sure they attend their second appointment – to keep themselves and those around them safe.”