Extension of the interval between vaccine doses for the BNT162b2 mRNA vaccine was introduced in the United Kingdom to accelerate population coverage with a single dose. At this time, trial data were lacking, and we addressed this in a study of United Kingdom healthcare workers. The first vaccine dose induced protection from infection from the circulating alpha (B.1.1.7) variant over several weeks. In a substudy of 589 individuals, we show that this single dose induces severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) neutralizing antibody (NAb) responses and a sustained B and T cell response to the spike protein. NAb levels were higher after the extended dosing interval (6-14 weeks) compared with the conventional 3- to 4-week regimen, accompanied by enrichment of CD4+ T cells expressing interleukin-2 (IL-2). Prior SARS-CoV-2 infection amplified and accelerated the response. These data on dynamic cellular and humoral responses indicate that extension of the dosing interval is an effective immunogenic protocol.
5699 - 5714.e11
Translational and Clinical Research Institute Immunity and Inflammation Theme, Newcastle University, Newcastle, UK. Electronic address: firstname.lastname@example.org.
PITCH Consortium, T-Lymphocytes, Humans, Immunoglobulin G, Vaccines, Synthetic, Antibodies, Viral, Treatment Outcome, Linear Models, Immunity, Cross-Priming, Dose-Response Relationship, Immunologic, Reference Standards, Adult, Aged, Middle Aged, Female, Male, Young Adult, Antibodies, Neutralizing, COVID-19, SARS-CoV-2, COVID-19 Vaccines, Ethnicity, BNT162 Vaccine