Albert Bourla, Pfizer CEO: A likely scenario is that there will be likely a need for a third dose, somewhere between six and 12 months and then from there, there will be an annual revaccination, but all of that needs to be confirmed. And again, the variants will play a key role.

CNBC: Researchers still don’t know how long protection against the virus lasts once someone has been fully vaccinated.

David Kessler, US Covid response chief science officer: We are studying the durability of the antibody response. It seems strong but there is some waning of that and no doubt the variants challenge ... they make these vaccines work harder. So I think for planning purposes, planning purposes only, I think we should expect that we may have to boost.

Again, this looks like a reading between the lines situation - which we are getting very good at.

Sounds like: 'Vaccines only work for 6 months, not effective against variants, get ready for annual shots, we'll need to trim down the safety trials even more - to save everyone'.