More than 2.5 million vulnerable people in England will be offered free Vitamin D supplements this winter.
The vitamin, which helps to keep bones, teeth and muscles healthy, will be delivered to people who are clinically extremely vulnerable, and care homes.
Skin makes Vitamin D when exposed to sunlight - but the elderly and those with dark skin need topping up.
The coronavirus pandemic means many more people than normal have spent time indoors.
The groups most at risk are residents in care homes, and people with serious health conditions which mean they have spent extended periods shielding from the virus - a total of 2.7 million people.
Health officials say that even in a normal winter, everyone should take 10 micrograms of Vitamin D a day between October and March - and it's particularly important this year because of coronavirus.