A new drug to treat covid could create a breeding ground for mutant viruses

What can be done? We can take some comfort in the FDA’s requiring Merck to report, within three months, the viral mutations induced by molnupiravir in clinical trial participants. Merck will also need to report viral mutations in immunocompromised patients, who are likely to harbor viruses longer. As this crucial information should have been supplied before approval, a responsible approach would be to limit molnupiravir use for the next three months to the best controlled settings. For example, health care providers could prescribe it only to people who live alone, or who live in managed care or nursing facilities where effective isolation can be implemented. And then it will be important for the FDA to be ready to revoke the emergency-use authorization if viable immunoevasive variants do indeed arise, even if only once.