In Michael Crichton’s 1969 book, The Andromeda Strain, the virus spared two people in the first town it infected, an old sterno-drinking man, who had a metabolic acidosis, and a crying baby, who had a respiratory alkalosis. These were the first clues that there might be a way to protect people.
A surprising news story in Boston revealed that none of the 146 homeless shelter clients who tested positive for COVID-19, out of 397 tested, had any symptoms. [1]
Homeless people in Boston often go long periods without eating, forcing their metabolism to adopt ketosis. Ketosis is known to have immunomodulatory effects. In studies of mice deliberately infected with influenza, fewer of them died if fed a ketogenic diet.[2]
A recent study of COVID-19 patients in NYC found that in people under 60 years, obesity was a greater risk factor for critical illness than even pre-existing cardiovascular or pulmonary disease. [3]
If we use obesity as a proxy for the frequent consumption of high-carb meals, and homelessness as a proxy for intermittent fasting and ketosis. This could be an Andromeda Strain type of clue that is worthy of further investigation.
Our ancestors may even have given us a clue with the folk wisdom of, “feed a cold, starve a fever.”
"Every one of these folks were asymptomatic. None of them had a fever, and none of them reported symptoms. So the usual screening tool we had been using in order to see who should be tested turned out to be essentially useless for us."
https://www.wbur.org/commonhealth/2020/04/14/coronavirus-boston-homeless-testingIn this study, we show that the consumption of a low-carbohydrate, high-fat ketogenic diet (KD) protects mice from lethal IAV infection and disease. KD feeding resulted in an expansion of γδ T cells in the lung that improved barrier functions, thereby enhancing antiviral resistance. Expansion of these protective γδ T cells required metabolic adaptation to a ketogenic diet because neither feeding mice a high-fat, high-carbohydrate diet nor providing chemical ketone body substrate that bypasses hepatic ketogenesis protected against infection.
https://immunology.sciencemag.org/content/4/41/eaav2026"The chronic condition with the strongest association with critical illness was obesity, with a substantially higher odds ratio than any cardiovascular or pulmonary disease," write lead author Christopher M. Petrilli of the NYU Grossman School and colleagues.
https://www.zdnet.com/article/nyu-scientists-largest-u-s-study-of-covid-19-finds-obesity-the-single-biggest-factor-in-new-york-critical-cases/