I've had the corona virus 16 times now including strains that haven't even been released from the lab. That being said, I never placard an inhalation hazard shipment because I don't have a sense of smell anymore.
If the DOT pulls me over and gets in the trailer, I open the product up and take a big old whiff in front of them to prove it's not hazardous. Then I scream the word "harassment" and pretend like I'm dialing a US Marshal in my phone contacts list.
They give me a clean level 1 and I get a personal call from Fred thanking me for delivering the purple promise.