The virus which causes COVID19 can produce severe inflammation called a cytokine storm, which can then set off a chain reaction which results in thrombosis (tiny blood clots), which can damage all of the organs in the body. This process is known as DIC (disseminated intravascular coagulation). As we age, we become more prone to thrombosis, which is why heart attacks and strokes are more common among the elderly. Men are more prone to thrombosis than women. Certain medical conditions put you at higher risk of thrombosis, including high blood pressure, high cholesterol, and diabetes. Smoking and eating processed foods increases the risk of thrombosis as well.
These are the reasons why COVID19 poses a higher risk for the elderly, for men, and for those with certain chronic medical conditions. If you have one of these conditions, the best thing you can do is to keep that condition under good control by taking your medication, eating healthy foods, exercising, avoiding smoking, and getting plenty of sleep and water.
For these same reasons, medications which lower your risk of heart attack and stroke seem to prevent COVID19 complications, such as statins like lipitor, ACE-inhibitors like lisinopril, and anti-coagulants such as aspirin and Plavix. N-acetyl cysteine and Vitamin C also help to decrease inflammation within blood vessels and prevent thrombosis. On the other hand, medications which increase your risk of heart attack and stroke, such as ibuprofen and other NSAIDs, also increase your risk of COVID19 complications. If you have cold or flu symptoms, you should avoid taking NSAIDs for fever and body aches and stick to Tylenol.
Antihistamines like Claritin decrease inflammation, and Claritin seems to help with COVID19 prevention. Vitamin D helps to suppress inflammation as well. In fact, Vitamin D and antihistamines decrease inflammation by the same molecular pathway as chloroquine. Zinc prevents viruses from replicating, so it is helpful in preventing COVID19. One of my colleagues works at one of the leading infectious disease centers in the US, and they are recommending the following regimen to all of their medical students and residents: Claritin 10 mg once daily and a multivitamin three times daily, in order to get adequate Zinc, Vitamin C and Vitamin D. Although I do not typically recommend daily multivitamins, during this pandemic, I am taking and recommending this regimen. Although the benefits have not been proven, the potential benefits outweigh the minimal risk of taking these supplements.