A doctor (infectious disease specialist) being interviewed on the radio also warned about this. He also said that just because the numbers showed the vaccines to be more than 90% effective in carefully conducted clinical trials, the numbers would likely be significantly lower in the real world.
Here in Canada, stupid political decisions are also compromising the effectiveness of the vaccines, because some provincial governments have decided (contrary to the vaccine mfgr's advice) not to reserve the second doses, and are using up their entire supply for first doses, then crossing their fingers hoping that more vaccines will arrive in time for the second dose. At the same time, Pfizer has announced that, starting immediately, they will reduce or completely stop shipments for a month, so that they can make changes to their plant in Belgium to increase production. So, I'm rather glad that I'm far enough down on the list, that things will be operating smoothly (hopefully) by the time I get my shot.
