One dose ‘enough to boost immune response’

The Pfizer/BioNTech vaccine generates a robust immune response in 99% of people after one dose, new research suggests.

One dose of the vaccine protects against severe disease and after two jabs, levels of protection are even stronger – underlining the importance of people coming forward for their second shot.

The findings support the UK policy of rapid rollout of one dose of vaccine to provide cover as quickly as possible for the higher-risk groups, researchers say.

The Protective Immunity from T cells to Covid-19 in Health workers study (Pitch) examined how the immune system responds to the virus after one dose of the Pfizer/BioNTech vaccine among people who have been previously infected, and those who have not.

Between December 9 last year and February 9, researchers from the universities of Sheffield, Oxford, Liverpool, Newcastle and Birmingham analysed blood samples from 237 health workers to understand their T cell and antibody responses following vaccination.

They found that after one dose of the Pfizer vaccine, individuals who had previous infection showed higher antibody and T cell responses compared with people who had not been infected before.

Antibody responses were 6.8 times higher and T cell responses were 5.9 times higher.

Among individuals who had not had the virus in the past and had received one dose of the jab, antibody and T cell responses were at a similar or higher level compared to those who had previously been infected but not been vaccinated.

As well as creating antibodies, the immune system produces T-cells in response to an infection.