On March 17 2020, just as the virus was taking hold in the UK and before the first lockdown was introduced, MailOnline reported that Chinese researchers found people with Type A blood are significantly more likely to catch coronavirus than those with Type O.
The study in Wuhan also found those with Type A blood are more likely to die from COVID-19.
In the general population Type O blood (34%) is more common than A (32%).
However, among COVID-19 patients, people with Type O accounted for just 25%, whereas Type A made up 41%.
People with Type O blood made up a quarter (25 per cent) of deaths in the research. Normally, Type O people make up 32 per cent of people in Wuhan.
Researchers in China assessed 2,173 people who had been diagnosed with the coronavirus, including 206 people who died after contracting the virus, from three hospitals in Hubei.
Academics compared the data of the infected Wuhan patients with 3,694 non-infected people in the same region.
Of the 206 patients in the study who died, 85 had type A blood, equivalent to 41 per cent of all deaths.
In the healthy Wuhan population, a city of 11 million people, 34 per cent of people are type A.
In the study cohort, 52 of the people who died were type O, making up a quarter of all deaths. Under normal conditions just 32 per cent of people are type O.
The figures for all infections, not just deaths, are 26 per cent and 38 per cent for type O and type A, respectively.
In November 2020, MailOnline again reported on a similar study which found people with type A blood are more at risk.
Researchers from the Institute for Clinical Evaluative Sciences in Toronto studied 225,556 people who had a blood test between 2007 and 2019 and a Covid swab in 2020.
It found people with a type O blood are 12 per cent less likely to catch the coronavirus than other blood types, a study has found.
It also revealed that those with a negative blood type (O-, A-, B- or AB-) are, on average, 21 per cent less likely to get the virus than people with a positive type.
Individuals with type O or negative blood are also 13 per cent and 19 per cent less likely to develop severe symptoms or die, respectively.
In the UK, around 15 per cent of the population have a negative blood type and almost half (around 48 per cent) are type O.
Around one in eight people (13 per cent) are O-, which are 26 per cent less likely to get infected and 28 per cent less likely to develop severe symptoms or die.