Airbnb's internal policy regarding the Novel Coronavirus Outbreak as of yesterday (1/28/2020) is now allowing host to cancel without penalty, and for guests to cancel and get full refund from China (entire Mainland China, not just Wuhan Region). The specific dates in their Extenuating Circumstances policy covers up to April 1st. (airbnb customer service is so secretive about it and won't point me to an official airbnb press release, possibly because it would trigger mass cancellation hurting their quarterly earnings while they are planning to take the company public this year.. hmmm... Profits over People??) If you work at airbnb and reading this, let your boss know that https://news.airbnb.com/ is doing a terrible piss poor job at communicating with the public.
In my opinion, the sensible thing for airbnb to do would be to publicly announce their policy of "voluntary" cancellations: and offer both host and guests a mix of 1. partial refund and 2. credit for future travel rather than allowing this mass panic of cancellations on both sides. Host would get some of the money to pay bills while trying to fill the newly formed vacancies, guests can use the credit for travel at a future date, airbnb gets their 12%-15% cut of revenue upfront (credit losses later for tax write-offs and for the good-will on the PR front) without clogging up their phone lines with pissed off customers.
So if you are a host, due to this current un-announced policy, there are many preventable "last minute cancellations" by the guests. If you have reservations from China I would suggest cancelling them early for the sake of preventing possible risk near your home, and give yourself time to fill the vacancy with guests from elsewhere. It's a loss for everyone, until airbnb does announce something sensible.