Having followed the news of the novel coronavirus for awhile now I would recommend vitamin C and vitamin d3. Vitamin C boosts the immune system and d3 is for those with no access to sunlight.
This is in addition to staying healthy, taking a multi vitamin, Omega 3, hand washing, personnel hygiene, drinking water/fluids, exercising, etc. Omega 3 is very useful for managing depression and other such anxieties. Drinking fluids washes out the system, so the water in the body isn't stale and stagnant.
In my opinion the reason that the Chinese are dying from this is that being quarantined restricts their supply to fresh air and sunlight. This is true of other maladies and is true of the novel coronavirus as well.