Vets have been using gut parasite posions for centuries. Anti-Bacterial drugs have been successful for about 90 years-but that's changing as more drug resistant bacteria evolve. Anti-Viral drugs only about 70 years-since the polio vaccine was developed in the 1950s. The vet prescribes ivermectin for my dog's pin worms. Covid19 is a viral infective and not a gut parasite.