the spread of further vocs with more spike protein mutations, primarily the much more contagious delta variant, meant higher antibody levels were needed to fight the virus and prevent it from causing serious infection.
thus it is not surprising that the combination of antibodies produced being less effective and their natural decay over time has led to small but increasing rates of infection in fully vaccinated people. while the all important protection from life threatening infection has remained very high after vaccination, this immunity is also starting to be pierced more frequently. as expected, breakthrough infections are occurring most commonly in people with initial low antibody production or higher rates of antibody decay.
the needed solution to waning immunity is booster shots, either with a third dose of the original vaccine available now, or with shots being developed that more specifically target the spike protein mutation of the voc.
given the highly contagious nature of the dominant delta variant and a residual pool of unvaccinated people, especially children, we are at increasing risk and need a detailed plan for boosters very soon. the key issue is what the priorities and timelines for the booster shot are and how prepared is canada to source and administer them. we can’t be caught as flat-footed as we were for the delayed initial vaccination program.