Abstract
Safe and effective coronavirus disease-19 (COVID-19) vaccines are urgently needed to control the ongoing pandemic. While single-dose vaccine regimens would provide multiple advantages, two doses may improve the magnitude and durability of immunity and protective efficacy. We assessed one- and two-dose regimens of the Ad26.COV2.S vaccine candidate in adult and aged nonhuman primates (NHPs). A two-dose Ad26.COV2.S regimen induced higher peak binding and neutralizing antibody responses compared with a single dose. In one-dose regimens, neutralizing antibody responses were stable for at least 14 wk, providing an early indication of durability. Ad26.COV2.S induced humoral immunity and T helper cell (Th cell) 1-skewed cellular responses in aged NHPs that were comparable to those in adult animals. Aged Ad26.COV2.S-vaccinated animals challenged 3 mo after dose 1 with a SARS-CoV-2 spike G614 variant showed near complete lower and substantial upper respiratory tract protection for both regimens. Neutralization of variants of concern by NHP sera was reduced for B.1.351 lineages while maintained for the B.1.1.7 lineage independent of Ad26.COV2.S vaccine regimen.
【초록키워드】 COVID-19, coronavirus disease, neutralizing antibody, Efficacy, Vaccine, coronavirus, pandemic, Immunity, B.1.351, neutralization, variants of concern, variants, B.1.1.7 lineage, Humoral immunity, Ad26.COV2.S, Coronavirus disease-19, B.1.1.7, NHPs, sera, Lineage, respiratory, upper respiratory tract, Neutralizing antibody response, single dose, Protective, binding, SARS-CoV-2 spike, cellular response, dose, regimen, independent of, T helper cell, helper cell, regimens, G614 variant, neutralizing antibody responses, Ad26, Ad26.COV2.S vaccine, while, two-dose regimen, Complete, NHP, effective, independent, Th cell, IMPROVE, magnitude, comparable, was reduced, 【제목키워드】 Efficacy, Vaccine, immunogenicity, COVID, dose, NHP,