Department for Transfusion Medicine, University Hospital of Salzburg (SALK), Paracelsus Medical University (PMU) Salzburg, Salzburg, Austria.
Austrian Red Cross, Blood Service for Vienna, Lower Austria and Burgenland, Vienna, Austria.
Infect Dis (Lond). 2024 Nov;56(11):954-964. doi: 10.1080/23744235.2024.2367112. Epub 2024 Jun 13.
Understanding the dynamics of SARS-CoV-2 reinfections is crucial for public health policy, vaccine development, and long-term disease management. However, data on reinfections in the general population remains scarce.
This study aimed to investigate SARS-CoV-2 antibody dynamics among Austrian blood donors, representing healthy adults, over two years following primary infection and to evaluate the reinfection risk.
117,895 blood donations were analysed for SARS-CoV-2 total anti-N levels from June 2020 to December 2023. We examined anti-N and anti-S antibody dynamics and functionality in 230 study participants at five defined times during 24 months, assessing associations with demographics, vaccination status, and reinfection awareness.
The seroprevalence of SARS-CoV-2 infection-derived anti-N antibodies increased over time, reaching 90% by February 2023 and remaining at that level since then. According to serological screenings, we found an 88% reinfection rate, which is in contrast to participants' reports indicating a reinfection rate of 59%. Our data further reveal that about 26% of reinfections went completely unnoticed. Antibody dynamics were independent of age, sex, and ABO blood group. Interestingly, individuals with multiple reinfections reported symptoms more frequently during their primary infection. Our results further show that vaccination modestly affected reinfection risk and disease course.
SARS-CoV-2 reinfections were uncommon until the end of 2021 but became common with the advent of Omicron. This study highlights the underestimation of reinfection rates in healthy adults and underscores the need for continued surveillance, which is an important support for public health policies and intervention strategies.
了解 SARS-CoV-2 再感染的动态对于公共卫生政策、疫苗开发和长期疾病管理至关重要。然而，一般人群中再感染的数据仍然很少。
本研究旨在调查奥地利献血者在初次感染后两年内 SARS-CoV-2 抗体的动态，并评估再感染的风险。
分析了 2020 年 6 月至 2023 年 12 月期间 117895 份献血样本的 SARS-CoV-2 总抗-N 水平。我们在 24 个月的 5 个时间点对 230 名研究参与者的抗-N 和抗-S 抗体动态和功能进行了检查，评估了与人口统计学、疫苗接种状况和再感染意识的关联。
SARS-CoV-2 感染衍生的抗-N 抗体的血清阳性率随时间推移而增加，到 2023 年 2 月达到 90%，此后一直保持在该水平。根据血清学筛查，我们发现再感染率为 88%，而参与者报告的再感染率为 59%。我们的数据进一步表明，约 26%的再感染完全没有被注意到。抗体动态与年龄、性别和 ABO 血型无关。有趣的是，多次再感染的个体在初次感染时更频繁地报告症状。我们的结果还表明，疫苗接种适度影响再感染风险和疾病过程。
SARS-CoV-2 再感染在 2021 年底之前很少见，但随着奥密克戎的出现变得常见。本研究强调了在健康成年人中再感染率的低估，并强调了需要持续监测，这是对公共卫生政策和干预策略的重要支持。
