are reported, covid vaccine makers are planning to tweak their shots to try to target the variant. take a listen now to what moderna is proposing to do to improve vaccine efficacy. >> i think we are going to learn this more definitively over the next 7 to 10 days. we are doing the experiments needed to assert -- to establish whether the reduction in binding that could be there, nevertheless, allows us to be protective against this variant virus. >> now, earlier i asked dr. scott muskovich if testing before travel would help prevent the spread of the new variant. here's his response. >> for the united states to only request one day, what happens if you caught the disease two days before, three days before? you may not be positive yet, and yet another day or two later you may be just fully shedding and spreading it. so many studies have shown that one-day testing is not enough to