"Despite ongoing vaccinations, we recommend raising serum 25(OH)D levels to above 50 ng/mL to prevent or mitigate new outbreaks due to escape mutations or decreasing antibody activity."
Occasionally, despite catastrophic Regime interference, an Academy-scientist ends up as a real-scientists and does some science.
As per the other study, to get 50ng/mL takes around 9000 IU. For preference my no-sun regime is 10,000. Previously, dieticians have been completely incompetent and/or straight-up evil, as per usual. "According to the Institute of Medicine, 4000 IU is the safe upper level of daily vitamin D intake."
Luckily this study will cause exactly nothing to happen, because vaccines are expensive patented medicines andthus profitable, and vitamin D is a cheap commodity with no associated monopoly kickbacks whatsoever.
You can't even put vitamin D in the water supply, because it's a fat-soluble nonpolar molecule.
Reminder: taking enough vitmain D/sunlight that your immune system works properly causes minor cosmetic side-effects if not also taken with expensive quantities of DHA/EPA. In a sense, 4000 is near the "safe" upper dose if looking good is more important to you than being inherently immune to colds &c.