After 
AJA two days ago cancelled its participation in NAB 2020, further cancellations were likely. And indeed, Nikon has now followed suit. Nikon&s statement in wording:
MELVILLE, NY - Nikon&s first priority is always the health and safety of our employees, partners and customers. As we continue to closely monitor and evaluate the effects of COVID-19, Nikon Inc. and MRMC, a Nikon Group company, have decided not to participate in NAB 2020. We will continue to closely evaluate our travel policies, programs and risk mitigation activities.>/quote>
A logical step, since the coronavirus is spreading in the USA and today California declared a state of emergency. It is to be expected that further cancellations will force the NAB to cancel the fair or (as has already happened at other events) to have it held online or postponed.
Other events such as the Adobe Summit at the end of March or the Nvidia "GTC - GPU Technology Conference" will no longer take place face to face, but will be held online, similar to what AJA has announced. Probably more NAB 2020 exhibitors will follow this example.
Here are some good places to go for information about the coronavirus:
- some rules of conduct for protection against the coronavirus
- 45 questions and answers about the coronavirus
- Information on COVID-19 from Robert Koch Institute
- A good place to inform yourself about the latest scientific studies and discuss them objectively is Reddit COVID-19 Subforum
