The country of Cuba has a better handle on the Covid-19 outbreak than most countries. However as of this posting one of the primary interstate bus systems is still not operating. Viazul operates across the country and is similar to Greyhound. I will need to verify if local buses are operating as Cuba will a little more than 11 million people only approximately one and one-half percent own a car. For the vast majority of people their primary mode of getting around is public transportation, taxis, hitching a ride, motorbikes, bicycles and walking.

Here is the official correspondence I received from Viazul headquarters.
viazul < viazul@eon.cu >To:‘Fred Thomas’Thu, Oct 8 at 3:46 PM
Currently all services are suspended as a security measure against Covid-19. The restart of our service is subject to the epidemiological situation of the country, this process will be done in phases and our operations must begin in the third stage. When the ticket sales opening date is defined, you will be informed through social networks, the website and the press. We apologize for any inconvenience this may cause.
attentively
VIAZUL Reservation Center
NATIONAL BUS COMPANY – CUBA
Email: viazul@eon.cu