Sera were collected from 185 adults aged ≥ 70 years in London to evaluate the immune response to COVID-19 vaccines . A single dose of Pfizer/BioNtech vaccine resulted in> 94% seropositivity after 3 weeks in naïve individuals using the Roche Spike antibody assay, while two doses produced very high spike antibody levels, significantly higher than convalescent sera from mild-to-moderate PCR-confirmed adult cases . Our findings support the United Kingdom's approach of prioritising the first dose and delaying the second dose of COVID-19 vaccine.
Index: Antibody, COVID-19, COVID-Vaccine, Immunity, Pfizer/BioNtech, Spike Protein