Bengaluru: An international team of scientists have launched a global search for people who are naturally genetically resistant to Covid, in an effort to identify protective genes and the development of future viral-blocking drugs.
If natural immunity to the disease exists, it could provide insights into developing drugs that could also prevent transmission of infection from an infected individual.
The team of researchers from 10 different research centres around the world aim to recruit candidates who were potentially exposed to the virus unprotected, but did not develop the disease, test positive for the virus, or have an immune response.
The researchers have launched the study following the 2017 discovery of natural genetic resistance through a mutation to the malaria-causing Plasmodium vivax parasite, as well as studies showing secondary Covid attack rates within households where all family members but one were infected despite close contact.
The study is described in the journal Nature Immunology.
Clues to genes, genetic mutation for Covid resistance
The study hopes to enroll at least 1,000 volunteers, primarily people who were free of infection despite their partner, with whom they had close physical interactions, falling sick.
Once such individuals have been shortlisted, the researchers will sequence their genome and compare it with those who have been infected. Such studies are called genome-wide association studies (GWAS) and yield information at a genetic level. The effort is expected to yield clues into any genes or genetic mutations associated with resistance to Covid.
The researchers hypothesize that some resistance mechanisms could be factors like a non-functioning or a reduced expression of the ACE2 receptor, which the virus uses to latch on to our cells. Such genetic mutations has been observed with HIV resistance or a natural HIV “cure” previously. There could also be mutations that could prevent viral replication or which destroys viral RNA within cells.
Once such genes are identified, they will be studied in cell cultures and animal models for further analysis.
The team has previously identified rare genetic mutations in individuals that make them more susceptible to severe Covid.
Over 500 potential candidates have already been recruited for the study, and since the publication of their paper outlining the study, about 600 people, including candidates from India, have volunteered as fitting the criteria, said an accompanying article in Nature.
(Edited by Poulomi Banerjee)