The study, which was published in Nature, was conducted by over 3,000 scientists from 25 countries and made up of 46 separate studies that were done in 19 countries.
The scientists compared the genetic codes of 50,000 people who have had COVID-19 and 2 million people who never contracted the disease. The people who had the virus were separated into three groups based on severity of their case.
Nine out of the 13 regions where there were genetic variations were linked to immune responses and lung-related conditions. This means that there is a clear biological explanation for COVID susceptibility.
The study included underrepresented countries such as Jordan, Iran, Latvia and Pakistan, meaning that researchers were able to find more genes that were mostly absent in Europeans but more prevalent in the East Asia population.
"Everyone talks about the virus genome, but the human genome matters," Said Andrea Ganna, senior researcher at the Institute for Molecular Medicine Finland, to Insider.
"Usually when performing genetic analysis, there's a lot of variation but it's not clear what the genes do so it's exciting to have plausible biological explanations for the differences observed,"
He added that there is still much work that needs to be done.
Since the study was initially conducted, more genetic variations have been discovered, but they have not yet been peer-reviewed.