Elderly patients aged more than 60 years and those with co-morbid conditions such as hypertension, diabetes, heart disease, chronic lung or liver or kidney disease, cerebrovascular disease etc shall only be allowed home isolation after a proper evaluation by the treating medical officer, it added.

In case of falling oxygen saturation levels or shortness of breath, the person should require hospital admission and seek immediate consultation with the treating physician or surveillance team.

“As vaccine roll outs continue to gain momentum it is important to remember that, despite a prior Covid-19 infection, young people can catch the virus again and may still transmit it to others,” said Professor Stuart Sealfon, of Icahn School of Medicine at Mount Sinai, a senior author of the study.

“Immunity is not guaranteed by past infection, and vaccinations that provide additional protection are still needed for those who have had Covid-19,” Sealfon said.

“A new study shows one dose of the vaccine can cut the risk of household transmission by up to 50 per cent. This is further evidence that the vaccine protects you and those around you. When you get the call, get the jab,” said UK Health Secretary Matt Hancock.