Unless you’ve hedged in advance of the drop, your options are:
1. Hedge late
3. Ride it out
#1 and #2 are busted by V-shaped recoveries, which no one can predict in this scenario. So that leaves #3 as the best choice for most people (i.e., you're not a professional investor trading VIX options, etc.).
Rolling the dice for #1 or #2 aren't advisable because pandemics like Coronavirus can happen in waves. Given that, our chances of getting the market timing correct are about as likely to be right as anyone who tried to guess the impact of Spanish flu nearly 100 years ago. If you're an everyday investor, be like Warren Buffett and think 10 years ahead. By that time, Coronavirus will be long gone.