a somewhat uncommon mechanism. it actually goes into the virus rna and stops it from replicating. that s good. you see the results that merck is reporting. however, there are concerns about off target effects. off target meaning maybe it might affect something in the human body s genetic system and not just the virus genetic system. experts tell me we don t have reason to fear this, however, it is hypothetically true. some experts told me they predict the fda will say not to use this, for example, for pregnant women or to use it cautiously with pregnant women for fears of the effect that it might, and i use the word might very strongly, might possibly have on a developing fetus. still concerning because there are questions that need to be answered here. elizabeth, i also wanted to ask about studies showing booster doses produce more immune response than the two vaccine doses alone. this is good news for people who