A team of researchers has found that an individual’s immune response to SARS-CoV-2 variants depends on their previous exposure to infections and vaccination, which could help optimise future vaccines.
The new study, published in the journal Science, involved collaboration across ten research institutes, including the University of Cambridge, and unveiled a snapshot of early global population immunity to COVID-19.
Vaccines provide individuals with immunity without risking the disease or its complications.
By activating the immune system to recognise and rapidly respond to exposure to the SARS-CoV-2 virus, vaccines prevent it from causing illness.
However, like other viruses, the SARS-CoV-2 virus continues to mutate to defy human immunity.
After collecting 207 serum samples from blood samples of people who had been infected by the SARS-CoV-2 variants or had previously been vaccinated against SARS-CoV-2 with a number of doses of the Moderna vaccine, the researchers analysed the immunity that they had developed.
Using a technique called antigenic cartography, the team compared the similarity of different SARS-CoV-2 virus variants to measure how well human antibodies formed in response to infection with one virus versus infection with a variant of it.
Funded by the National Institute of Allergy and Infectious Diseases and National Institutes of health, the study discovered significant differences between immune responses depending on which variant an individual had been infected with first.
As a result, the antigenic map revealed the relationship between a wide selection of SARS-CoV-2 variants that have previously circulated.
“If the virus mutates in a specific region, some people’s immune system will not recognise the virus as well,” said Dr Samuel Wilks, Centre for Pathogen Evolution, Department of Zoology, University of Cambridge.
Omicron variants were noticeably different from others, which explained why individuals still succumbed to infection with Omicron despite previous vaccination or infection with a different variant.
“These results give us a deep understanding of how we might optimise the design of COVID-19 booster vaccines in the future,” said Professor Derek Smith, director, Centre for Pathogen Evolution, Department of Zoology, University of Cambridge.
He added: “We want to know the key virus variants to use in vaccines to best protect people in the future.”