More than likely it would not stay active in something like that. But I dont think that scientists have tried putting coronavirus in/on drugs toner how long they can survive. If you can, wait a day before use just to be sure. Chances are, if you get sick a week or so after using it, your dealer has covid and doesnt wash his hands...
A virus can survive ouside a living host in 2 to 3 days, so in those terms heroin are safe. But if a Corona-infected person makes bags of heroin without using gloves there is a small chance of contracting the virus. But I underline small.
What should worry some users is the fact that closed boarders is many countries will make it harder to distribute large amounts of heroin and other drugs resulting in a low(er) supply of drugs making them harder to find and result in increasing prices. In Denmark we have experienced a small surge in drug users seeking substitutions treatment because heroin is harder to come by.
So if you really want to be safe now is the time to stock pile drugs. If the situations should turn out for the worse many drugs like pain killers and benzo might be directed away from the general publib and towards hospitals and people whom really need it. But it is really a worst case senario. But the security surrounding critical infrastructures in several countries have been increased dramatically.