Many more people may have been infected with coronavirus and acquired immunity than previously thought, according to a groundbreaking study in Germany.

Scientists studying the town at the epicentre of the country's first major outbreak said they had found antibodies to the virus in people who had shown no symptoms and were not previously thought to have been infected.

Initial results released on Thursday suggest that as many as 15 per cent of people in Gangelt, in Heinsberg district, may already have immunity – three times as many as previous estimates.

The findings suggest the mortality rate for the virus in Germany is just 0.37 per cent — five times lower than current estimates.

"This means a gradual relaxation of the lockdown is now possible," Prof Hendrik Streeck, the virologist leading the study, told a press conference. "Because the people in Germany have been so careful and disciplined, we are now able to move on to the second phase."