Can vitamin C prevent or treat COVID-19?

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Vitamin C is an antioxidant, which means that it can fight oxidative damage. When the immune system activates to kill a pathogen, it may also cause oxidative damage. This suggests that vitamin C could fight the damage that the disease-fighting process causes.

It also aids healthy immune function by supporting the development of white blood cells.

In its role as an antioxidant, vitamin C may also help fight inflammation, which can damage the lungs and other organs. Some evidence suggests that people with severe COVID-19 experience dangerous levels of inflammation.

However, a 2020 paper cautions that very high doses of vitamin C may change the way immune cells die, increasing the risk of localized inflammation. The authors recommend adding a steroid treatment called a glucocorticoid to reduce this inflammation.

Vitamin C levels also tend to decline when a person is unwell, even though the immune system’s need for this vitamin increases. Some doctors believe that taking vitamin C supplements can help prevent this depletion, thereby supporting the immune system.

Vitamin C causes few side effects, even at high doses. This means that it may be a safer alternative to riskier treatments.

A handful of papers have suggested that vitamin C may help treat inflammation and symptoms associated with COVID-19. At least one clinical trial testing this is underway, but it will not finish until September 2020.

For now, the research supporting the use of vitamin C for COVID-19 has looked at conditions such as acute respiratory distress syndrome and the need for mechanical ventilation due to severe cases of COVD-19. It has not looked specifically at people with COVID-19.

A 2020 meta-analysis of nine existing clinical trials compared a group of people who received an IV infusion with a group of controls. The researchers found that, on average, vitamin C shortened the length of mechanical ventilation by 14%. The effect varied from study to study, though, and it was larger when members of the control group needed longer periods of ventilation.

A 2019 meta-analysis found that vitamin C infusions could shorten the length of intensive care unit stays by 7.8% and the need for mechanical ventilation by 18.2%. The study looked at a wide range of medical conditions, but not at COVID-19.

A 2019 randomized controlled trial looked at people with sepsis and severe acute respiratory failure, which are two complications that people with severe COVID-19 may experience. Participants received either a placebo or a vitamin C infusion. Although vitamin C did not decrease the rate of organ failure or sepsis, fewer people in the vitamin C group died.

A 2018 study compared people with severe pneumonia who received a vitamin C, thiamine, and hydrocortisone infusion with those who did not. The study authors adjusted for possible differences in the group but still found that the vitamin C group had better outcomes. Specifically, they were less likely to die and had better improvements in their lung scans.

Although doctors have experimented with different treatments for COVID-19, they have not yet discovered an effective treatment or cure.

Most people are appropriately relying on prevention, while some have turned to alternative remedies and supplements to reduce their risk and to ease the infection.

There is currently little evidence to suggest that any treatment is effective against COVID-19. People should talk to their doctor to discuss measures that will improve their health and protect them from COVID-19 and its complications.

People with underlying medical conditions should try to focus on better managing their health conditions instead of trying experimental remedies or supplements that may not work.

Taking preventive measures against COVID-19 is also important. The Centers for Disease Control and Prevention (CDC) share the following tips:

• Cover the nose and mouth with a face mask when around others, especially when in close contact. Learn more about face masks here.
• Frequently wash the hands with warm, soapy water. Wash the hands before eating, after using the bathroom, after coming into contact with others, and before touching the face or mouth. Learn proper hand-washing techniques here.
• Use hand sanitizer containing alcohol when it is not possible to wash the hands with soap.
• Avoid touching the face and mouth.
• Avoid coming into contact with people outside of the household, if possible.
• Try to stay 6 feet (2 meters) away from others when in public areas.
• Cover all coughs and sneezes with a cloth or handkerchief.
• Regularly disinfect all surfaces that people frequently touch, such as doorknobs and counters.
• Avoid going out in public with symptoms of illness, unless it is necessary to seek medical attention.

Learn more about preventing the spread of coronavirus here.

Vitamin D

No research has yet confirmed that vitamin D can play a role in the treatment of COVID-19.

Like vitamin C, vitamin D also plays a key role in immune function. Emerging evidence suggests that people with vitamin D deficiencies may have worse outcomes if they develop COVID-19.

A 2017 study suggests that vitamin D may protect against severe respiratory tract infections.

Also, at least 14 clinical trials are underway to test the role of vitamin D in treating or preventing COVID-19. Currently, no evidence supports the use of vitamin C or D in treating COVID-19.

Currently, research suggests that vitamin C may help reduce the severity of complications related to COVID-19, but it may not treat or prevent the condition itself.

COVID-19 is a new disease. Research continually changes as researchers enroll more participants in more studies. As the pandemic progresses, so will medical knowledge about how to treat and prevent it and whether or not any specific home remedies are effective.

Without more information, it is impossible to know for sure which treatments might work and which might make it worse. People who have or think they have COVID-19 should stay at home and consult a doctor about the best care strategies.