promising, and merck has already submit add similar medication to the fda for emergency use authorization. an infection disease specialist is with us and host of the epidemic podcast. always good to see you. how does this treatment work and why is this so potentially significant? >> fredricka, the pfizer drug paxlovid is similar to drugs used to treat other viruses like hiv or help site is c and we call it a protease inhibitor. big picture important to understand about the drug, it works by a different mechanism of action than the merck drug m mollnupurivir and have great potential for treating covid as a single factor alone or perhaps in combination with one another.