Genetic variability in the human immune system may affect susceptibility to, and severity of infection by SARS-CoV-2, the virus that causes the coronavirus disease (COVID-19).
The findings published in the Journal of Virology may help shed new light into the puzzling question of why the disease hits some people harder than others.
Certain immune system genes, called human leukocyte antigen genes that are involved in recognising pathogens, vary from person to person.
These variations can influence how well the immune system recognises a given pathogen.
Poor recognition of SARS-CoV-2 could cause a person to be more vulnerable to the virus, said the study.
"In particular, understanding how variation in HLA (a component of the immune system containing multiple genes) may affect the course of COVID-19 could help identify individuals at higher risk from the disease," according to the authors of the new study.
The authors showed that individual HLA, haplotype, and full genotype variability likely influence the capacity to respond to SARS-CoV-2 infection, and noted that certain alleles in particular could be associated with more severe infection, as has previously been shown with SARS-CoV.
"This is the first study to report global distributions of HLA types and haplotypes with potential epidemiological ramifications in the setting of the current pandemic," said the authors from Oregon Health & Science University, Portland, and the Portland VA Research Foundation in the US.
"HLA typing can be fast and inexpensive," the authors wrote.
"Pairing HLA typing with COVID-19 testing where feasible could improve assessment of viral severity in the population. Following the development of a vaccine against SARS-CoV-2, the virus that causes COVID-19, individuals with high-risk HLA types could be prioritized for vaccination."