Can I extend my Immigrant visa due to COVID-19?

[RabbitHole]

I received my employment-based immigrant visa (NIW) in late March. The visa expires in late August. I must enter the US with my family before the visa expiration date.
Due to COVID-19 I am reluctant of getting on a plane with my family. Also, the CDC requires me to stay in quarantine for 14 days after arriving in the US.
Is it possible to apply for an immigrant visa extension based on the above, given the global situation?

[R78]

No... these are temporary approvals to enter the country and no exceptions have been allowed as of now.
if you cannot enter within the expiry, you need to get a new stamp

[RabbitHole]

I understand. What would be the process of getting a new stamp? Would a new interview have to be scheduled? Would a new medical exam?

[R78]

Your case was approved so no need for a new medical exam. Just a new immigrant visa sticker (you may be eligible to apply via dropbox)