COVID-19 Vaccines

Vaccine-induced immunity against Omicron was not fully negated, as some neutralizing capacity remained. For allergy-prone individuals, a physician-recommended pre-vaccination protocol includes H1 antihistamines such as Claritin or Zyrtec, but explicitly excludes Benadryl. The Pfizer-BioNTech vaccine produces neutralizing antibodies that are substantially less effective against Omicron than against the ancestral strain. Dr. Ashton's vaccine decision was driven primarily by concern about long-COVID outcomes — specifically persistent neurological impairment and myocarditis with lasting cardiac damage — rather than by fear of death from COVID. The anaphylaxis risk from the Pfizer vaccine was initially estimated at less than 1 in 1,000,000 but was subsequently revised to approximately 1 in 90,000. Prophylactic antihistamine use before COVID vaccination is not recommended for the general public because some people have adverse reactions to antihistamines themselves, creating a new risk layer at scale. Three COVID-19 vaccines were available in the United States at the time of the recording: Pfizer-BioNTech, Moderna, and Johnson & Johnson.