Scientists believe a person’s response to SARS-CoV-2 viruses that cause COVID-19 will depend on how and where they were previously exposed – this knowledge will allow scientists to tailor future vaccines more effectively in providing broad protection.
New research suggests that individuals may differ significantly in how susceptible they are to different mutations of emerging variants of SARS-CoV-2 virus.
As this depends on which variant of SARS-CoV-2 people were initially exposed to, their immune systems will respond differently when exposed to different parts of it and determine their resilience against other variants.
Meaning the same COVID-19 vaccine could work differently for different people depending on what variants of SARS-CoV-2 they’ve previously been exposed to and where their immune responses have focused.
This discovery underlines the necessity of continuing surveillance programs to detect new variants, and to assess population immune status to SARS-CoV-2.
Future vaccination strategies must take this information into account as well, taking into account both which variant of influenza virus is included in each vaccine and how individuals within each population might differ in terms of immune reactions to it.
Surprised at how disparate immune reactions to SARS-CoV-2 among different people were, we witnessed much variation between their bodies’ immune reactions. Immune cells appear to target different regions depending on which variant their bodies had experienced first.
Dr. Samuel Wilks of Cambridge’s Centre for Pathogen Evolution Department of Zoology published the report as its author.
“Our results indicate that if a virus mutates in any given region, some individuals’ immune systems might no longer recognize it and could become susceptible to illness, while other may still provide enough immunity against its spread to remain protected against illness.”
Research published today in Science involved collaboration among 10 research institutes including Cambridge and produced an accurate snapshot of early global population immunity to COVID-19.
Researchers collected 207 serum samples extracted from blood samples collected from people either naturally infected with one of several previously-circulating SARS-CoV-2 variants or who had received various dosages of Moderna vaccine against SARS-CoV-2 infection.
Researchers studied how immunity had developed among these individuals, discovering significant variations between immune responses depending on which variant a person had first come in contact with.
“These findings provide us with a deeper insight into how we might optimize the design of COVID-19 booster vaccines going forward,” stated Professor Derek Smith of Cambridge’s Centre for Pathogen Evolution within Department of Zoology as senior author of this report.
He added: “Our aim is to identify which virus strains should be included in vaccines to provide optimal protection in the future.”
Researchers used an antigenic cartography technique to compare different variants of SARS-CoV-2 virus. This evaluates how effectively human antibodies generated following infection with one strain respond to infection with its variant; and in turn demonstrates whether enough has changed about an infectious agent so as to evade human immunity and cause disease in its place.
Antigenic maps demonstrate how Omicron variants differ significantly from others that had circulated, providing insight into why many individuals succumbed to infection with it despite vaccination or previous infection with another strain.
Immunity to COVID-19 may be obtained either through infection with SARS-CoV-2 virus or vaccination, with vaccination providing immunity without risk. They work by stimulating immune system response so it will respond more rapidly when exposed to this strain of virus and prevent illness arising; but like all viruses it continues mutating to circumvent immunity of humans.
At first, B.1 SARS-CoV-2 virus was the predominant form in circulation during this pandemic; since then however, several variants have emerged which bypass preexisting immunity to cause reinfection in people who already had COVID.
“This study provided us with an opportunity to study from initial exposure of SARS-CoV-2 onward what factors determine people’s immunity to it, as well as any differences across populations,” according to Wilks.
This research was funded by the National Institute of Allergy and Infectious Diseases as well as National Institutes of Health. Journal reference:Wilks, S. H. et al (2023). Mapping SARS-CoV-2 antigenic relationships and serological responses in Science. http://dx.doi.org/10.1126/science.adj0070
