I wouldn't undermine vitamin D3, as well as good nutrition and excercise to get the biggest bang for a healthy immune system. Most or all of us here are athletes and should already know this...right? (I'm a grandmasters and have been competing in so many different sports from my college football days in the early 80s up to now as a GM in triathlon).
An anecdotal on my experience with D3:
Back during the first week of this past February, my 20 yr old son, who is a student-athlete at a local university, came home pretty sick with flu-like symptoms - he shut it down and went into survival mode. Two days later, I woke up also sick and felt like I just got hit by a Mack truck. All flu-like symptoms with breathing difficulties for me (I haven't had been this sick for over 10 yrs). Since our symptoms were very similar to those of COVID-19, I called my primary care doctor about it who said it's probably
not COVID but a case of the
severe flu - and that it would probably take "5-6 weeks" to completely recover and return back to full training (gee... thanks doc).
After several days of absolutely no improvement from basic OTC meds, I didn't panicked and for the both of us, ramped our vitamin D3 significantly (we both take a lower dose throughout the year and I get plenty of sun in the summer). Within a few days we both felt tremendously better and I could breath again. All in all - it was about 10 days downtime where I lost 12 lbs, quite bit of muscle mass and virtually all CV fitness. I gently returned to running/riding and weight workouts getting back to pre-illness levels in about 3 weeks - and I'm no spring chicken either. My son took far less time to recover, obviously being much younger.
I really believe the D3 was the point turning point. A lot of people have low D3 levels. Most of us in northern two-thirds of the country can't get any sun during the winter months. And even in the summer months many people use sunscreen which impairs the synthesis of D3 from the sun. Low D3 levels impair our immune system's ability to fight off viral & bacterial infections. D3 can also downregulate the
cytokine storm seen in cases of a hyperactive-immune response to pathogens:
Researchers analyzed patient data from 10 countries. The team found a correlation between low vitamin D levels and hyperactive immune systems. Vitamin D strengthens innate immunity and prevents overactive immune responses. The finding could explain several mysteries, including why children are...
www.sciencedaily.com
Also, excercise can prevent or at least reduce the severity of ARDS by producing a key antioxidant (EcSOD):
Researcher Zhen Yan, PhD, is urging people to exercise based on his COVID-19 findings, which also suggest a potential treatment approach.
newsroom.uvahealth.com
And the one thing that irks me is the WH medical staff's reluctancy in advocating a healthy diet, excercise and certain supplements like D3 during this pandemic. I haven't heard Fauci, Birx nor the Surgeon General say anything about this. All three are MDs, with Fauci who runs several miles everyday, and Brix & Adams both in the military (Birx inactive but reached the rank of Colonel in the Army reserves).
This is obviously a strong respiratory virus that can be challenging to a healthy immune system and we have a such poor state of health in this country with so many sick, ill & sedentary people. Something like 100 million Americans with
hypertension, over 100 million with
diabetes/prediabetes, another 75 million with
cardiovascular disease and a 40% OBESITY rate! It shouldn't be shock & awe that so many people are developing complications from this virus. These people should have been dumping the junk food and eating healthy, getting excercise & increasing their vitamin D levels. But yet so many continue their bad habits and remain terrified of getting the virus. These are the same people who lack personal responsibility and expect the government to protect them at all costs. The same people who clog up the healthcare system with so many
preventable chronic ailments (even before COVID), and expect the government to solve their problems for them. If I can do it at my age (plus I have
post-traumatic OA from injuries sustained in a serious car accident several years ago), then most people should be able to it!
A sad state of affairs with the health of this country!