We report that in a cohort of 45,965 adults, who were receiving either the ChAdOx1 or the BNT162b2 SARS-CoV-2 vaccines, in those who had no prior infection with SARS-CoV-2, seroconversion rates and quantitative antibody levels after a single dose were lower in older individuals, especially in those aged >60 years. Two vaccine doses achieved high responses across all ages. Antibody levels increased more slowly and to lower levels with a single dose of ChAdOx1 compared with a single dose of BNT162b2, but waned following a single dose of BNT162b2 in older individuals. In descriptive latent class models, we identified four responder subgroups, including a ‘low responder’ group that more commonly consisted of people aged >75 years, males and individuals with long-term health conditions. Given our findings, we propose that available vaccines should be prioritized for those not previously infected and that second doses should be prioritized for individuals aged >60 years. Further data are needed to better understand the extent to which quantitative antibody responses are associated with vaccine-mediated protection.

我们报告说，在 45,965 名接受 ChAdOx1 或 BNT162b2 SARS-CoV-2 疫苗的成年人中，对于那些既往没有感染过 SARS-CoV-2 的人，单剂接种后的血清转化率和定量抗体水平老年人的比例较低，尤其是 60 岁以上的人。两种疫苗剂量在所有年龄段都取得了很高的反应。与单剂量 BNT162b2 相比，单剂量 ChAdOx1 的抗体水平增加更慢且水平较低，但在老年人中单剂量 BNT162b2 后抗体水平下降。在描述性潜在类别模型中，我们确定了四个响应者亚组，包括“低响应者”组，该组通常由年龄 > 75 岁的人、男性和患有长期健康状况的个人组成。鉴于我们的研究结果，我们建议应优先为以前未感染过的人接种可用疫苗，并应优先为年龄 > 60 岁的人接种第二剂疫苗。需要进一步的数据来更好地了解定量抗体反应与疫苗介导的保护相关的程度。