Abstract
The coronavirus 2019 omicron variant has surged rapidly and raises concerns about immune evasion even in individuals with complete vaccination, because it harbors mutations. Here we examine the capability of booster vaccination following CoronaVac/AZD1222 prime to induce neutralizing antibodies (NAbs) against omicron (BA.1 and BA.2) and T-cell responses. A total of 167 participants primed with heterologous CoronaVac/AZD1222 for 4-5 months were enrolled, to receive AZD1222, BNT162b2, or mRNA-1273 as a third dose. Reactogenicity was recorded. Immunogenicity analyses of severe acute respiratory syndrome coronavirus 2-binding antibodies were measured using enzyme-linked immunosorbent assay. The NAb titers against omicron BA.1 and BA.2 were determined using the focus reduction neutralization test (FRNT50) and total interferon-γ responses were measured to observe the T-cell activation. A substantial loss in neutralizing potency to omicron variant was found at 4-5 months after receiving the heterologous CoronaVac/AZD1222. Following booster vaccination, a significant increase in binding antibodies and neutralizing activities toward delta and omicron variants was observed. Neutralization to omicron BA.1 and BA.2 were comparable, showing the highest titers after boosted mRNA-1273 followed by BNT162b2 and AZD1222. In addition, individuals boosted with messenger RNA (mRNA) vaccines develop a T-cell response to spike protein, whereas those boosted with AZD1222 did not. Reactogenicity was mild to moderate without serious adverse events. Our findings demonstrated that mRNA booster vaccination is able to overcome waning immunity to provide antibodies that neutralize omicron BA.1 and BA.2, as well as a T-cell response.
Keywords: AZD1222; COVID-19; booster vaccine; heterologous; mRNA vaccine; omicron.
【저자키워드】 COVID-19, mRNA vaccine, AZD1222, Heterologous, Omicron., Booster vaccine, 【초록키워드】 neutralizing antibody, Vaccine, coronavirus, vaccination, antibody, mRNA-1273, neutralization, T-cell Response, mutations, Spike protein, BNT162b2, immune evasion, Neutralizing activity, mRNA, response, Mild, Omicron variant, Neutralizing, Coronavirus 2019, moderate, booster, T-cell responses, booster vaccination, dose, waning immunity, binding antibody, reduction, Serious Adverse Events, Messenger RNA, interferon-γ, acute respiratory syndrome, significant increase, individual, NAbs, participant, T-cell activation, Complete, neutralize, NAb titer, enzyme-linked immunosorbent, raise, observé, enrolled, highest, develop, addition, receiving, overcome, demonstrated, induce, comparable, were measured, receive, Immunogenicity analysis, was recorded, 【제목키워드】 immune response, vaccination, mRNA, Effect, adenoviral-vectored vaccine,