According to a recent study, it has been seen that a single dose of COVID-19 vaccine boosts protection against SARS-CoV2 coronavirus variants, but only if those who are previously infected with the disease.
The researchers had checked the UK and South African variants but also, they think that it is possible that the findings will apply to other variants in circulation, like the Brazil (P.1) and India (B.1.617 and B.1.618) variants.
Those who have not previously been infected and have so far only received one dose of vaccine their immune response to coronavirus variants of concerns may be insufficient, showed, the findings published in the Journal science.
However, other researchers at Imperial College London, Queen Mary University of London and University College London also looked into the immune response in UK healthcare workers at Barts and Royal Free hospitals following their first dose of the Pfizer/BioNTech vaccine.
According to the findings they found that people who had previously had mild or asymptomatic infection had significantly improved protection against the Kent and South Africa variants, after a single dose of the mRNA vaccine and it was also seen that the immune was less strong after a first dose in those without prior Covid-19 were potentially at risk from other variants.
Rosemary Boyton, Professor of Immunology and Respiratory Medicine at Imperial College London, who led the research said, “Our findings show that people who have had their first dose of vaccine, and who have not previously been infected with SARS-CoV-2, are not fully protected against the circulating variants of concern.”
“This study highlights the importance of getting second doses of the vaccine rolled out to protect the population,” Boyton said.
However, the blood samples were analysed by the researchers for the presence and levels of immunity against the original strain of SARS-CoV-2, as well as the variants of concern were Kent (B.1.1.7) and South Africa (B.1.351).
The researchers along with antibodies, also focused on two types of white blood cell: B-cells, which ‘remember’ the virus, and T cells, which help B cell memory and recognise and destroy cells infected with coronavirus.
According to their findings it was seen that they found that after a first dose of vaccine, the initial infection was associated with a boosted T cell, B cell and neutralising antibody response, which could provide effective protection against SARS-CoV-2, as well as the Kent and South Africa variants.
In people without previous SARS-CoV2 infection, a single vaccine dose resulted in lower levels of neutralising antibodies against SARS-CoV-2 and the variants and leaving them at risk to infection and highlighting the importance of the second dose of vaccine.
However, it remains unclear that precisely how much protection is offered by T cells.
As compared to the original strain the mutations in the Kent and South Africa variants resulted in T cell immunity which could be reduced, enhanced or unchanged that also depends on genetic differences between people.
“Our data show that natural infection alone may not provide sufficient immunity against the variants,” Boyton said.
“Boosting with a single vaccine dose in people with prior infection probably does. As new variants continue to emerge, it is important to fast track global rollout of vaccines to reduce transmission of the virus and remove the opportunities for new variants to arise,” she said.