Science
Prior coronavirus infection boosts response to variants after first vaccine dose
BHF-funded researchers have found that a single dose of vaccine boosts protection against coronavirus variants, but only in those with previous Covid-19.
The study was published today in Science and suggests that in those who have not previously been infected and have only received one dose of vaccine, the immune response to variants of concern may be insufficient.
Researchers looked at the immune responses in 731 UK healthcare workers at Barts Health NHS trust and Royal Free Hospital following their first dose of the Pfizer/BioNTech vaccine. They found that people who previously had mild or asymptomatic infection had a significantly enhanced protection against the Kent and South Africa variants, after a single dose of the mRNA vaccine. In those without prior Covid-19, the immune response was less strong after a first dose, potentially leaving them at risk from variants.
Boosted immune response in Covid-19 patients
Blood samples were analysed for the presence and levels of immunity against the original strain of SARS-CoV-2, as well as the Kent (B.1.1.7) and South Africa (B.1.351) variants of concern. They looked at the responses of antibodies and two types of white blood cell: B-cells, which ‘remember’ the virus, and T cells, which help B cell memory and destroy cells infected with coronavirus.
They found that after a first dose of vaccine, prior infection was associated with a boosted T cell, B cell and neutralizing antibody response, which could provide effective protection against SARS-CoV-2, as well as the Kent and South Africa variants.
However, in people without previous SARS-CoV-2 infection, a single vaccine dose resulted in lower levels of neutralizing antibodies against SARS-CoV-2 and the variants, potentially leaving them vulnerable to infection.
Second vaccine doses are vital
The researchers emphasise that the study highlights the importance of getting second doses of the vaccine rolled out to protect the population.
Professor James Moon, BHF-funded researcher at Barts Health and University College London, said: “These results represent collaborative science at its best between hospitals, universities and public bodies providing important timely results to inform policy and strategy.”
The study was carried out in collaboration with researchers at Barts Health NHS Trust, Public Health England, Royal Free Hospital NHS Trust, University College London and University of Nottingham.