A new study has found that people differ in how vulnerable they are to different mutations in emerging variants of SARS-CoV-2.
This is because the variant of SARS-CoV-2 a person was first exposed to determines how well their immune system responds to different parts of the virus, and how protected they are against other variants.
It also means that the same COVID-19 vaccine might work differently for different people, depending on which variants of SARS-CoV-2 they have previously been exposed to and where their immune response has focused.
The research, published in the journal Science, involved a large-scale collaboration across ten research institutes including the University of Cambridge and produced a comprehensive snapshot of early global population immunity to COVID-19.
Researchers collected 207 serum samples - extracted from blood samples - from people who had either been infected naturally with one of the many previously circulating SARS-CoV-2 variants, or who had been vaccinated against SARS-CoV-2 with different numbers of doses of the Moderna vaccine.
They then analyzed the immunity these people had developed and found significant differences between immune responses depending on which variant a person had been infected with first.
The research used a technique called ‘antigenic cartography’ to compare the similarity of different variants of the SARS-CoV-2 virus. This measures how well human antibodies, formed in response to infection with one virus, respond to infection with a variant of that virus. It shows whether the virus has changed enough to escape the human immune response and cause disease.
The resulting ‘antigenic map’ shows the relationship between a wide selection of SARS-CoV-2 variants that have previously circulated. Omicron variants are noticeably different from the others – which helps to explain why many people still succumbed to infection with Omicron despite vaccination or previous infection with a different variant.