Researchers worldwide are conducting extensive research to understand the nature of the virus. They have found a strong correlation between the ABO blood group and SARS-CoV-2 regarding its morbidity and mortality. New research from India published on a preprint server has associated blood group ABO and asymptomatic COVID-19.
This study used random serosurveillance and blood group testing of street vendors in northern India. The data was collected from 509 individuals from three districts of the eastern Uttar Pradesh region. Researchers have reported that the seroprevalence of all the districts considered in this study was greater than 0.4.
This increased seroprevalence indicates that the majority of SARS-CoV-2 infections were owing to asymptomatic infections. The blood group of SARS-CoV-2 infected individuals was estimated and grouped. Scientists have reported that the ABO blood group distribution of 215 seropositive people showed 0.223, 0.312, 0.107, and 0.358 frequency of A, B, O, and AB blood groups, respectively.
In this study, a considerable inconsistency was found in the relative blood group distribution, especially between O and AB. Among the seropositive group, the blood group AB was significantly higher, while blood group O was significantly lower. This result is similar to the previously published data on seropositive individuals. Thereby, the current research has established a strong association of blood groups O and AB with COVID-19 susceptibility. While assessing which blood group is more at risk of COVID-19 infection, scientists revealed that individuals with blood group AB are at a much higher risk of getting COVID-19 infection than individuals with blood group O type.
This research developed a risk scale which indicated that individuals with blood group AB are most susceptible or at the highest risk of being infected with SARS-CoV-2, followed by blood group A and B. However, blood group O is placed at the lower end of this risk scale, indicating this blood group is at a considerably lower risk of being infected. Previous research stated that Rh-negative blood type plays a protective role against SARS-CoV-2. This study did not find any link between the Rh factor and COVID-19.
However, it must be mentioned that there were a limited number of Rh-negative samples. One of the limitations of this study is that it did not consider data on individuals who are severely infected with SARS-CoV-2. Thereby, the relationship between blood group and COVID-19 severity is not projected. However, one interesting outcome of the research is that even though the AB blood group is most susceptible to COVID-19 infection, it may not be at a high risk of severity.