Coronavirus could "burn out naturally before any vaccine is developed", according to a former World Health Organisation chief.
"We are seeing a roughly similar pattern everywhere – I suspect we have more immunity than estimated," Professor Karol Sikora, who previously directed the WHO's cancer programme, said on Saturday.
"We need to keep slowing the virus, but it could be petering out by itself. It is my opinion that this is a feasible scenario."
His hopeful comments come days after a new study in the International Journal of Clinical Practice, using local authority "R" transmission rate data, estimated some 19 million people are "likely" to have already contracted the virus in the UK.
Recent polling by Opinium suggests the public are similarly pinning their hopes on a vaccine. Researchers found more than a quarter of UK respondents said they would not feel comfortable taking public transport until a vaccine is found.
Meanwhile, Moderna Inc yesterday said its experimental COVID-19 vaccine showed promise in a small early-stage trial, with the vaccine producing virus-neutralizing antibodies similar to that found in recovered patients.
Eight patients who were administered Moderna's vaccine were found to have antibody levels similar to those in blood samples of people who have recovered from COVID-19, according to early results from the study.
Moderna expects to start a larger late-stage trial in July.
There are currently no approved treatment or vaccine for COVID-19 and experts predict a safe and effective vaccine could take 12-18 months to develop.