With the United States quickly approaching 29 million confirmed cases of coronavirus  and more than 500,000 deaths, fear continues to climb. In response to the emerging COVID-19 crisis, the Eastern Virginia Medical School (EVMS) Medical Group has responded with an updated approach to preventative and critical care based on the most recent literature and the Shanghai Management Guideline for COVID.
Dr. Paul Marik, developer of the EVMS Critical Care COVID-19 Protocol , shares his one-page summary  outlining the newest guidelines for patients at all stages of infection. While a majority of the protocol is a guideline for professional medical doctors and nurses, there are natural suggestions for at-home care that may bolster immunity and have antiviral properties.
Although the supplements outlined in the data are unspecific to COVID-19, the low-cost and readily-available cocktail just might mitigate the disease by supporting healthy immune system functions. If you are over the age of 60, struggle with pre-existing medical conditions, or if you simply want to be proactive in preventive measures, now might be a good time to consult with your healthcare provider about which of these could be an effective addition to your daily routine and what dosages are right for you.
Five Natural Remedies to Strengthen Immunity
1. Vitamin C
Ascorbic acid (Vitamin C) is well known as an immune-enhancer able to curtail viral activity, boost antioxidant levels, lessen inflammatory response, and bolster immunity. A current clinical trial  using IV vitamin C for COVID is being conducted in response to a lack of targeted antiviral drugs. Based on past studies, it was hypothesized that vitamin C infusions could improve the prognosis of patients with severe acute respiratory infection (SARI). “When sepsis happens, the cytokine surge caused by sepsis is activated, and neutrophils accumulate in the lungs, destroying alveolar capillaries. Early clinical studies have shown that vitamin C can effectively prevent this process,” as noted in the clinical trial description.
But while IV vitamin C is being studied specifically for use in COVID-19 patients, data is not yet conclusive, and it cannot be easily administered at home without a doctor’s prescription. However, it is well documented that oral form vitamin C can be safely used to provide preventative immune support.
- Suggested Immune Support Dosage: 500 mg twice daily
Zinc is another potent viral inhibitor, particularly when coupled with vitamin C. A deficiency in zinc may hinder the body’s innate immune response, impairing its ability to adequately defend against pathogens using a variety of physical, chemical, and cellular mechanisms. When paired together, both zinc and vitamin C work synergistically to sustain immune health and fortify the body against infections. They may work in tandem to reduce the risk, length, and severity of illness.
While zinc is not advised to be taken for more than one to two months at a time, it is good to use when feeling especially vulnerable to acute exposure. Zinc lozenges are considered the best delivery, but any form that contains zinc acetate, gluconate, or picolinate is ideal.
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- Suggested Immune Support Dosage: 75-100 mg once daily
Quercetin, a natural pigment present in plant compounds known as flavonoids, is one of the most abundant antioxidants in the diet. The average person consumes up to 100 mg of these flavonoids naturally through their diet from food sources such as citrus, berries, broccoli, leafy vegetables, tomatoes, red grapes, and tea. When taken alone as a supplement, quercetin is not readily absorbed, which is why it is often combined with vitamin C or digestive enzymes, like bromelain, to increase bioavailability. Quercetin has broad antiviral properties and inhibits heat shock proteins required for viral assembly, making it a powerful addition to the immune-protecting cocktail.
- Suggested Immune Support Dosage: 250-500 mg twice daily
Melatonin, a naturally-occurring hormone produced by the brain in response to darkness, is most widely known in its supplemental form as a natural sleep aid. Aside from helping the body fall asleep faster and stay asleep longer, recent data suggests that it is also a strong antioxidant, anti-inflammatory, and immune modulator. Sleep is the time when our body does most of its self-repairing work, and it is essential as a solid foundation for health. After age 40, melatonin production levels drop significantly, making sleep and immune health lower as well. One 2013 study  determined that melatonin acted as a stimulant in immunosuppressed conditions, and as a regulator in overactive responses, such as septic shock. Although it’s generally safe for most adults, consider consulting with a doctor before using it — there may be some contraindications in people with high blood pressure, diabetes, seizures, and more.
- Suggested Immune Support Dosage: A slow release of 0.3 mg, increasing to 1-2 mg at night, as tolerated
5. Vitamin D3
During winter, most of the population experiences less than optimal levels of vitamin D due to lack of sun exposure. When vitamin D levels are low, the risk of developing upper respiratory tract infections increases. A 2011 study  concluded that when you have a vitamin D deficiency, you’re more susceptible to infections — not to mention autoimmune conditions, too.
Due to its immune-strengthening effect, vitamin D should be a great tool to defend against infectious agents, especially in elderly individuals or those living above 40 degrees latitude. Consider getting your levels tested by your doctor. If you are testing below 25 OH, you’ll likely benefit from vitamin D supplementation.
- Suggested Immune Support Dosage: 1000-4000 u/day
Combine this supplement cocktail with healthy habits, including adequate rest , stress reduction techniques, minimizing your consumption of alcohol, a nutritious diet , and exercise as tolerated , and you’ll be well on your way to giving your immune system the best chance of warding off infections now and throughout the year.
Also, it’s a good idea to gather contact information for local clinics and hospitals and educate yourself on the current operating procedures for local testing and hospital admission if you experience symptoms related to covid-19. With much information transforming daily, it is crucial to stay updated in the event you or a loved one should require medical intervention.
This article, originally published on April 6, 2020, was updated on March 1, 2021.