Researchers have identified a version of a particular Gene that could be why some individuals who test positive for the coronavirus never develop COVID-19 symptoms. This discovery could open new avenues for developing vaccines and treatments.
Studies have shown that at least 20 percent of people contracting the SARS-CoV-2 virus are Asymptomatic. Scientists believe these individuals possess quicker immune responses that help them fight off the virus before symptoms manifest and lead to health complications.
To understand how some people can fend off COVID-19 symptoms, scientists focused on human leukocyte antigen (HLA) genes, which play a crucial role in recognizing and fighting pathogens. These genes are considered the most medically necessary region of the genome.
The study, published in Nature, involved 29,947 volunteer bone marrow donors selected due to the availability of high-quality genetic data. Participants used their smartphones daily to track coronavirus infections and any resulting symptoms. Of the 1,428 unvaccinated individuals who reported a positive coronavirus test during the nine-month study period, 136 had no signs. Among the asymptomatic participants, 20 percent carried a common variant of the HLA gene, called HLA-B*15:01. Individuals with two copies of this variant (one from each parent) were more than eight times more likely to remain asymptomatic than those carrying other HLA variants.
Additionally, the researchers examined samples from people carrying the HLA-B*15:01 variant collected before the pandemic. These individuals had immune cells called T cells that reacted to proteins shared by SARS-CoV-2 and other seasonal coronaviruses. This suggests that carriers exposed to seasonal cold viruses may have developed preexisting immunity to COVID-19.
Although the results shed light on the reasons behind some asymptomatic infections, the study's limitations include its reliance on existing genetic data and the homogeneity of the study group, consisting mainly of White participants. However, the findings represent a crucial step in understanding asymptomatic cases, potentially influencing public health strategies, vaccine development, and therapeutics for COVID-19.
