Vitamin D deficiency is extraordinarily common, and most people don’t even realize they’re suffering from it.

Vitamin D has been used during the treatment of COVID-19 patients. Many people are taking it to prevent severe infections and some believe it could help strengthen their immune system to improve the vaccine’s efficacy.

Several recent studies have looked at the impact of vitamin D and zinc on COVID-19. One study of 489 people found that those who had a vitamin D deficiency were more likely to test positive for the virus. The most notable, President Trump, received a mixture of vitamin D and zinc along with a number of other experimental drugs. Ask your doctor for a blood test to determine how much vitamin D you may need with an over-the-counter pill. Vitamin D deficiency is particularly common among Hispanic and black people, two groups who have been disproportionately affected by COVID-19, according to the Mayo Clinic.

Having a strong immune system is always important, but it seems to be even more so in the coronavirus pandemic. A strong immune system won’t prevent you from getting the coronavirus, but it does reduce the odds of contracting it and can help you stave it off if there is a positive diagnosis. Here are eight vitamins that help boost your immune system -- and examples of foods that contain them if you don’t want to swallow any supplemental pills, according to the Cleveland Clinic. Notable foods that contain it: There are lot of foods that contain Vitamin C, including orange and grapefruit juice, broccoli, cauliflower, kale, kiwi, spinach, papaya, tomatoes and strawberries. Notable foods that contain it: Chicken, turkey, seafood, beans, broccoli, kale.