Millions of US residents need Covid-19 vaccines brought to them because they rarely or never leave home. Doctors and nurses who specialise in home care are leading this push and starting to get help from state and local governments around the country, AP reports.

But they face several challenges. Researchers say many homebound people don’t receive regular medical care, which makes it hard to identify everyone who needs a vaccine.

Supplies are also limited, and both the Pfizer and Moderna vaccines expire a few hours after syringes pull the vaccine from vials.