Michaels, Robert A. Possible SARS-CoV-2 persistence: FDA and CDC should further expand eligibility for Covid-19 boosters. ResearchGate, https://www.researchgate.net/publication/355175962_Possible_SARS-CoV-2_Persistence_FDA_and_CDC_Should_Further_Expand_Eligibility_for_Covid-19_Boosters, 11 October 2021

In the Fall of 2021, the US FDA and CDC expanded eligibility for Pfizer Covid-19 booster shots but imposed inadvisable restrictions. Two issues support unrestricted booster eligibility: SARS-CoV-2 is strongly selected for exploiting personal immunological weaknesses, resulting in weakened immune protection and slower immune response with increasing viral adaptation. Further, the virus might be persistent, which means that it might remain dormant in immune-privileged ‘refugia’ such as the central nervous system of previously infected people, even if their Covid-19 symptoms had been mild or non-existent. Opportunistic re-activation of dormant viruses can cause severe illness, as in childhood chickenpox producing adult shingles decades later. External re-infection is unnecessary. Consistent with the ‘precautionary principle’, the overriding FDA and CDC public health priority should be to prevent as many SARS-CoV-2 infections as possible, not tolerate them, assuming optimistically that they will not impose major public health and associated economic burdens in the future.