Are you talking about a ultra-super-duper-triple-hard lockdown? /sarcasm off/
The other day, I read a piece on the Brit numbers and someone suggested that a vitamin D deficiency (because of limited sunlight throughout the year anyway)...might be chief problem in the UK spiral.
It could be lack of Vitamin D. It has been theorized that one reason darker-skinned people get sick and die from COVID at higher rates than lighter-skinned people is lower levels of D, too. Older people also need supplementation, as they do not synthesize it as well as younger people. Anyone living more than 30 degrees from the equator needs extra vitamin D in the winter to keep immune system robust.