From memory when the vaccines were announced -
Pfizer - 94.5% effective, sample 40,000 although in another BBc segment there was a statement made that 20,000 were vaccinated and 20,000 control group i.e. placebo, over all age groups
Mederna - 90-95% effective, sample 30,000, over all age groups
AZ - 62% effective with two full doses, 90% effective with a half dose followed by a full dose - they could not understand way this was showing up in the test results, sample 20,000, over all age groups (noted that the trail groups were in Brazil and another location.
Pfizer first dose, then second dose 3 weeks later, possible immunity 7 days later i.e. 4 weeks to a month after the first dose, seems that the others may have the same timescale.
I predict that within the next 24 to 48 hours Yorkshire and the North West will move into tier 4 due the Saturday Super-spreader train event.
Another thought, assuming that come 1 January 2021 when WTO tariffs are applied to goods from the EU arrive (as I do not expect that a deal will be made), then will a tariff be applied to the remaining 39 million + doses that the Government will have to fork out for.