Distrito Sanitario Granada-Metropolitano, Granada, Spain.
Escuela Andaluza de Salud Pública, Granada, Spain.
Gerontology. 2022;68(8):910-916. doi: 10.1159/000519711. Epub 2021 Nov 10.
Older adults living in long-term care facilities (LTCFs) are at increased risk for severe outcomes from COVID-19 and were identified as a priority group in COVID-19 vaccination strategies. Emerging evidence suggests vaccine effectiveness in LTCF populations, but data about median and long-term durability of immune response after vaccination are still limited.
In this study, we assessed the humoral response to BNT162b2 mRNA COVID-19 vaccine 3 months after the second dose, in a cohort of 495 residents aged ≥65 years from 11 LTCF in Granada, Spain.
Between April 19 and April 30, 2021, we measured anti-SARS-CoV-2 Spike IgG to evaluate the humoral vaccination response. Antibody titers were reported in binding antibody units (BAU/mL). Bivariate and multivariate logistic regression models were performed to investigate the impact of age, sex, underlying health conditions, and prior COVID-19 infection on the antibody levels.
Over 96% of the participants developed an adequate humoral response. We detected higher antibody titers in previously infected individuals, compared with those previously uninfected (B: 1,150.059 BAU/mL, p < 0.001). Moreover, we found a significant inverse association between age and antibody levels (B: -7.943 BAU/mL, p < 0.05). This negative age-dependent response was more noticeable among residents over 85 years old. In contrast, baseline health conditions and cognitive status were not associated with different antibody levels.
These findings support monitoring COVID-19 vaccination response trend in older adults, in order to optimize future disease prevention and control strategies in this vulnerable population.
长期护理机构（LTCF）中的老年人感染 COVID-19 后出现严重后果的风险增加，因此被确定为 COVID-19 疫苗接种策略的重点人群。新出现的证据表明 LTCF 人群中的疫苗有效性，但关于接种疫苗后免疫反应的中位数和长期持久性的数据仍然有限。
在这项研究中，我们评估了西班牙格拉纳达 11 家 LTCF 中 495 名年龄≥65 岁的居民接种 BNT162b2 mRNA COVID-19 疫苗 3 个月后的体液反应。
在 2021 年 4 月 19 日至 4 月 30 日期间，我们测量了针对 SARS-CoV-2 刺突蛋白 IgG 的抗体以评估体液疫苗反应。抗体滴度以结合抗体单位（BAU/mL）报告。采用双变量和多变量逻辑回归模型，研究年龄、性别、基础健康状况和既往 COVID-19 感染对抗体水平的影响。
超过 96%的参与者产生了足够的体液反应。与未感染者相比，既往感染者的抗体滴度更高（B：1150.059 BAU/mL，p<0.001）。此外，我们发现年龄与抗体水平呈显著负相关（B：-7.943 BAU/mL，p<0.05）。这种负相关在 85 岁以上的居民中更为明显。相比之下，基线健康状况和认知状态与不同的抗体水平无关。
这些发现支持监测老年人 COVID-19 疫苗接种反应趋势，以便为这一脆弱人群优化未来的疾病预防和控制策略。
