Hi, good question!
The NIH has released an update on the impact of COVID-19 and submissions here.
Basically, if your business is officially closed or unable to submit grant applications due to COVID-19, or if NIH is officially closed because of the impact of COVID-19, the NIH will consider the acceptance of late submissions on a case-by-case basis. So if you think there will be issues with meeting the deadline because of COVID-19, reach out to your Program Officer as soon as possible to see whether you qualify for a late submission.
Stay safe, and wash your hands!
-Wout