A new study has found that 99% of people generate a robust immune response against COVID-19 after just one dose of the Pfizer vaccine, and that after two doses levels of protection were even stronger.
The PITCH (Protective Immunity from T cells to COVID-19 in Health workers) study, led by Oxford and Sheffield Universities with support from the UK Coronavirus Immunology Consortium, 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.
Between 9 December 2020 and 9 February 2021, researchers from the Universities of Sheffield, Oxford, Liverpool, Newcastle and Birmingham analysed blood samples from 237 healthcare workers to understand their T cell and antibody responses following vaccination from the Pfizer vaccine.