As scientists race to develop effective treatments or even a vaccine against COVID-19, people are clearly looking to reduce their risk of getting sick. Help could be found in a medicine cabinet — or simply looking up.

Vitamin D can strengthen the immune system, and we can get a daily dose just by being in the sun for a bit.

Adequate Vitamin D may potentially provide some modest protection for vulnerable populations, said Dr. Tom Frieden, the former CDC Director said earlier this week.

There is evidence of seasonality in some respiratory illnesses, including influenza and tuberculosis. A leading hypothesis is that seasonality is due to the reduction in Vitamin D because of decreased exposure to sunlight in winter months. There is no seasonality of influenza or tuberculosis in some tropical climates (such as south India), where weather – and sunlight exposure – remains more constant throughout the year.

Frieden said there’s no current link to Vitamin D deficiency and the severity of COVID-19. But given the high prevalence of Vitamin D deficiency in this country, it is safe to recommend that people get the proper daily dosage of Vitamin D.

Most people’s bodies manufacture Vitamin D in the skin when exposed to the sun. About 15 minutes a day of direct sunlight is sufficient for many people’s bodies to manufacture enough Vitamin D; people with darker skin need longer exposure to sunlight to manufacture the same amount. In foods, few are naturally rich in vitamin D (egg yolks and fatty fish such as salmon are two), making fortified foods and vitamin supplements important. We have been adding Vitamin D to milk for nearly a century, originally to reduce rickets, which is why most children are not Vitamin D deficient.

So for now, For now, go outside and get some sun, but make sure you follow social distancing guidelines to avoid close contact with other people, and don’t go out if you’re ill or can’t go out safely. Taking a walk will also help you get physical activity and alleviate cabin fever.