iScience - SARS-CoV-2 neutralization following infection and or vaccination

The elicitation of cross-variant neutralizing antibodies against SARS-CoV-2 represents a major goal for current COVID-19 vaccine strategies. Additionally, natural infection may also contribute to broaden neutralizing responses. To assess the contribution of vaccines and natural infection, we cross-sectionally analyzed plasma neutralization titers of six groups of individuals, organized according to the number of vaccines they received and their SARS-CoV-2 infection history. Two doses of vaccine had a limited capacity to generate cross-neutralizing antibodies against Omicron variants of concern (VOCs) in uninfected individuals, but efficiently synergized with previous natural immunization in convalescent individuals. In contrast, booster dose had a critical impact on broadening the cross-neutralizing response in uninfected individuals, to level similar to hybrid immunity, while still improving cross-neutralizing responses in convalescent individuals. Omicron breakthrough infection improved cross-neutralization of Omicron subvariants but only in non-previously infected vaccinated individuals. Together this data suggests that ancestral spike-based immunization remains a valuable strategy to provide broad SARS-CoV-2 immunity.诱导针对新型冠状病毒（SARS-CoV-2）的跨变异株中和抗体，是当前新型冠状病毒肺炎（COVID-19）疫苗研发策略的核心目标。此外，自然感染亦可助力拓宽中和免疫应答范围。为评估疫苗接种与自然感染的免疫贡献，我们基于受试者的疫苗接种剂次与新型冠状病毒感染史，将其划分为六组，并对各组受试者的血浆中和抗体滴度开展了横断面分析。在未感染个体中，两剂次疫苗诱导针对奥密克戎关切变异株（VOCs）的跨变异株中和抗体的能力有限，但在既往感染康复者体内，可与先前的自然免疫产生高效协同效应。与之相反，加强针接种对未感染个体的跨变异株中和免疫应答拓宽具有关键作用，可使其应答水平达到与混合免疫相当的程度，同时仍可改善康复者的跨变异株中和免疫应答。奥密克戎突破性感染可提升对奥密克戎亚变异株的中和活性，但该效果仅见于既往未感染的疫苗接种者。综合以上研究数据表明，基于原始毒株刺突蛋白的免疫策略仍是实现新型冠状病毒广谱免疫的有效方案。