Health Secretary Sajid Javid called it a “historic day for our country.” For once that might not be an overstatement. Beyond Britain, the new drug should be a reminder of the importance of antivirals in the fight against this and future pandemics. Friday’s announcement by Pfizer Inc. of even better results for its home remedy — an 89% reduction of hospitalizations and deaths in late-stage trials — suggest it won’t be far behind. Pfizer, whose shares jumped on the news, is seeking emergency use authorization in the U.S.