Fewer than 10 per cent of Americans have antibodies that could protect them from developing Covid-19, according to the first nationally representative survey that shows the vast majority still have not developed an immune response to the virus.

The serological survey of dialysis patients, published in the medical journal The Lancet on Friday, also found that black and Hispanic communities had two to four times higher rates of antibodies to Sars-Cov-2, the virus that causes Covid-19, after they were hit harder by outbreaks earlier this year. 

The Lancet survey was conducted on more than 28,000 dialysis patients, who were easy to follow because they regularly have blood drawn and access to healthcare through Medicare. They also tend to be older and more likely to live in poverty, which have been identified as risk factors for Covid-19.