SARS-CoV-2 transmittable chances are high from one person to the others in the family. One 2020 review indicates that, on average, the chances of SARS-CoV-2 transmitting to other family members is 16.9%. In households made up of the person with the infection and one other contact, transmittable chances increase 41.5%. Some people will not develop the infection even after prolonged contact with family members affected by the infection. This suggests that these people may be resistant to SARS-CoV-2 infection.
Genetic factors play an essential role in determining response to infectious disease. A recent review has summarized current evidence about genetic factors that could explain the variability in individual response to SARS-CoV-2 infection. Genes that may result in increased susceptibility are described by it and those that could potentially confer resistance. The researchers participating in the Covid Human Genetic Effort authored the review.
Identifying genes that may confer natural resistance against SARS-CoV-2 is of significant importance. It could help identify pathways involved in the fight against Covid and enable a better understanding of the pathogenesis of Covid. It could lead to the development of new therapeutics. Scientists have found genes mutations that influence or involve the type-1 interferon response in people with severe Covid. In the immune system, type-1 interferons are essentially chemical messengers and are essential to the antiviral response.
Certain gene types can also protect a person from severe illness and even resist infectious diseases. Several candidate genes have been identified by scientists that could potentially confer resistance against SARS-CoV-2 infection. By binding to the angiotensin-converting enzyme 2 (ACE2), protein SARS-CoV-2 enters human cells, expressed on the surface of a wide variety of cells.
A recent study found that a rare gene type close to the ACE2 gene is associated with a lower risk of SARS-CoV-2 infection and severe illness. These protective may result from the gene’s type ability to reduce ACE2 expression. It also influences the entry of SARS-CoV-2. Identifying individuals with a natural resistance to the infection is required for the characterization of genes that confer resistance to SARS-CoV-2. However, there are a few major methodological obstacles.
One is to show that a person has been affected with SARS-CoV-2 in the past. Polymerase chain reaction only provides information about recent exposure to the virus. Prior information about SARS-CoV infection can be provided while detecting antibodies in plasma samples. A small percentage of people who have had the infection do not have detectable levels of antibodies. It is difficult to differentiate among people who have never been exposed to the virus from those who possess natural resistance.
In the recent study to find out people with natural resistance to SARS-CoV-2 infection, the researchers want to enrol participants who are not affected by the virus but have family members with symptoms of Covid, especially a spouse or partner. They also want to include participants who are not affected by the virus but have been in contact with the asymptomatic person without protective equipment during the 1st 3-5 days of their infection. Along with PCR and antibody testing, the researchers wants to assess the participant’s T-cell responses.
The immune response to the infection is characterized by a response by T cells and the production of antibodies. The absence of a prior SARS-CoV-2 is confirmed by the lack of a T-cell response specific to the virus and negative PCR and antibody tests.