Dr. Ronan Glynn:

Different vaccines can have different impacts on the issue of transmission. We need to learn more about that in the coming weeks. Different variants will have different effects on different vaccines. We are seeing increasing reports on a daily basis, or certainly a weekly basis, internationally of cases and clusters arising among people who have been fully vaccinated, particularly in cases involving the B.1.351 South African variant. There is still a question as to the length of immunity or protection that is afforded by vaccine-induced immunity. There is also the whole issue of certification and our ability to stand over the validity or to authenticate-----