One thing that might help for the general population could be iron supplements. Not to prevent infection but to help the body to respond to low oxygen levels if you become infected.
Maybe. There's a pre-print, not-(yet?)-peer-reviewed paper[0] that theorizes that SARS-Cov-2 directly inhibits the ability of red blood cells to carry oxygen by binding in the place of iron (approximately)[1].
If this is true, then iron supplements could be dangerous, as too much iron is toxic, possibly fatal.
[0] The paper's abstract explicitly calls out the status of the research: "This paper is only for academic discussion, the correctness needs to be confirmed by other laboratories. Due to the side effects and allergic reactions of drugs such as chloroquine, please consult a qualified doctor for treatment details, and do not take the medicine yourself."
If this is true, then iron supplements could be dangerous, as too much iron is toxic, possibly fatal.
[0] The paper's abstract explicitly calls out the status of the research: "This paper is only for academic discussion, the correctness needs to be confirmed by other laboratories. Due to the side effects and allergic reactions of drugs such as chloroquine, please consult a qualified doctor for treatment details, and do not take the medicine yourself."
[1] https://chemrxiv.org/articles/COVID-19_Disease_ORF8_and_Surf...