pfizer is winning the game for now, securing both vaccines and treatment (not forgetting pfizer also have many other treatments in other therapies). Merck's drop should be temporary. Govt would be stocking up on both brands. Also Merck has many other good therapies in the pipeline - a value stock. The pills and vaccines will work hand in hand. Between Moderna and Biontech, I'd go for Biontech with more advanced and diversified pipeline. Cheers!