Wash your hands often, don't touch your face, and carry alcohol sanitizer. Maintain your mental health as well. Remember you have far less chance of catching this than the common flu, and most people will recover from both.
I'm a lot more worried about the economic effects of the pandemic than about the actual disease as I'm young and healthy. But I think now is the time to buy a big sack of rice and beans, just in case.
If your portfolio is diversified, e.g. via an index following the S&P 500, I don't see a reason to worry. Trying to time the whole market with short-term bets is a gamble, not a long-term strategy.
The stock market is not the economy. Many businesses and schools will be closed down. That massively impacts people who often don't even have a few hundred dollars on hand for an emergency.
