Prof Matteo Bassetti, head of the infectious diseases clinic at the Policlinico San Martino hospital in Italy, told The Telegraph that Covid-19 has been losing its virulence in the last month and patients who would have previously died are now recovering. The expert in critical care said the plummeting number of cases could mean a vaccine is no longer needed as the virus might never return. The clinical impression I have is that the virus is changing in severity," said Prof Bassetti. "In March and early April the patterns were completely different. People were coming to the emergency department with a very difficult to manage illness and they needed oxygen and ventilation, some developed pneumonia. "Now, in the past four weeks, the picture has completely changed. There could be a lower viral load in the respiratory tract, probably due to a genetic mutation in the virus which has not yet been demonstrated scientifically. Even elderly patients, aged 80 or 90, are now sitting up in bed and they are breathing without help. The same patients would have died in two or three days before. "I think the virus has mutated because our immune system reacts to the virus and we have a lower viral load now due to the lockdown, mask-wearing, social distancing. "Yes, probably it could go away completely without a vaccine." Prof Karol Sikora ... at Rutherford Health previously said it is likely the British public has more immunity than previously thought and Covid-19 could end up "petering out by itself".