Japan is home to an untold number of conveniences and delights that American consumers regularly go without: Faster public transit! Better sunscreen! Lychee KitKats! But as we head into sick season, one Japanese invention would be especially welcome on the U.S. market: an antiviral pill that appears to shorten COVID symptoms, might protect against chronic disease, and doesn’t taste like soapy grapefruit. Ensitrelvir, a drug made by the Osaka-based pharmaceutical company Shionogi, was conditionally approved in Japan last November. Like Paxlovid, ensitrelvir works by blocking an enzyme that the SARS-CoV-2 virus uses to clone itself inside the human body. But for the millions of Americans who will likely get COVID in the coming months, the new drug is almost certain to be out of reach. In 2021, Pfizer waited just five weeks for Paxlovid to receive its emergency use authorization. But ensitrelvir is still sitting in the approval pipeline, stuck in another round of clinical trials that may run well into 2024. Existing data (not all of which have been peer-reviewed) show that people with …