According to scientists and doctors working 24×7 on finding a vaccine or cure for COVID-19, no one is safe from the viral infection. Be it a healthy person with a strong immune system or a newborn baby, everyone is at risk of contracting the virus if they get exposed. However, the preliminary results of a recent study conducted by a US-based biotechnology company, 23andMe, showed that people with O-type blood group are less likely to get infected with the COVID-19 causing virus. The study has not been published yet as more research is being done on the topic.
The blood group study
23andMe is a biotech firm that deals with genetic analysis and testing. On 6 April 2020, the firm started studying the relationship of genes with COVID-19 infection. The research was done on a large scale as it involved more than 7.5 lakh people. Later, by the end of May, the study was expanded further and included an additional 10,000 people who had severe COVID-19 infection. This expanded study is still being carried out.
In the study, the scientists tested the blood samples and the genetic design of these 7.5 lakh people. They were divided into three groups; the ones who self-reported COVID-19 infection, the ones who were hospitalised and the ones who got infected after a known exposure.
Preliminary results of the study
The preliminary results of the study suggested amongst all the subjects, people with O blood type were the least likely to get infected. To be specific, they found that individuals with O blood type were around 9-18 percent less likely to test positive for COVID-19 than individuals with other blood types.
The results remained the same even after adjusting the individuals on the basis of age, sex, body mass index, ethnicity, and co-morbidities.
They also found that amongst those who were directly exposed to the infection, such as healthcare workers and other front line workers, people with blood group O were 13-26 percent less likely to test positive for COVID-19 than individuals with other blood types.
The study further indicated that people with blood group AB were the most likely to test positive for COVID-19 infection, followed by blood group B and then blood group A.
The scientists did not take the Rhesus factor (plus or minus blood groups) into account during the study.
Previous studies supporting the role of blood groups in COVID-19
Similar studies have been reported in the past which indicated the relationship between COVID-19 infection and blood type.
On 27 March 2020, a Chinese study conducted on 2,200 people concluded that people with blood group A were at a higher risk of getting the infection and blood group O was associated with lower risk.
A similar Italian-Spanish study stated that blood group A was associated with a higher infection rate whereas the O blood group showed protective effects against COVID-19 infection.