Longitudinal study on SARS-CoV-2 antibody responses in companion animals, Chile

SARS-CoV-2 infection susceptibility in dogs and cats has been documented, with identified risk factors contributing to transmission dynamics. Understanding viral prevalence and the evolution of emerging variants across pandemic waves can clarify the potential role of pets as reservoirs. This study evaluated 3298 serum samples (1921 dogs, 1377 cats) collected from 2020 to 2024. Samples were analyzed using ELISA and viral neutralization assays, revealing a positivity rate of 2.7%. We assessed neutralizing antibody titers (nAbs) against the Wuhan-Hu-1 and Omicron BA.1 strains, finding higher titers in felines compared to canines. A marked reduction in samples exceeding the detection limit was observed after November 2022. Longitudinal data from up to 30 months in a dog and 15 months in two cats demonstrated sustained antibody responses, with increased nAb titers in 7 of 14 monitored animals. Multivariable logistic regression of 275 samples indicated that a pet’s vaccination status was associated with an increased risk of infection, while spring season, the owner’s number of COVID-19 vaccinations, and the owner’s vaccination status were protective factors. These results emphasize the significance of vaccination strategies for both human and animal health, supporting the One Health approach.

目前已有研究证实犬与猫对严重急性呼吸综合征冠状病毒2型（SARS-CoV-2）具有易感性，且已明确若干影响病毒传播动态的风险因素。厘清新冠大流行各波次中病毒的流行态势与新兴变异株的演化规律，有助于阐明宠物作为病毒储存宿主的潜在作用。本研究对2020年至2024年间采集的3298份血清样本（其中犬样本1921份、猫样本1377份）开展分析。采用酶联免疫吸附试验（ELISA）与病毒中和试验对样本进行检测后，整体阳性率为2.7%。本研究针对Wuhan-Hu-1株与奥密克戎BA.1（Omicron BA.1）株检测了中和抗体效价（neutralizing antibody titers, nAbs），结果显示猫科动物的中和抗体效价显著高于犬科动物。2022年11月后，检测阈值以上的阳性样本数量出现显著下降。对1只犬进行最长30个月、对2只猫进行最长15个月的纵向追踪数据显示，受试动物的抗体应答持续存在，其中14只监测动物中有7只的中和抗体效价出现升高。对275份样本开展多变量logistic回归分析后结果显示：宠物自身的疫苗接种状态与感染风险升高显著相关，而春季、主人的新型冠状病毒肺炎（COVID-19）疫苗接种剂次以及主人的疫苗接种状态均为保护因素。上述研究结果凸显了兼顾人类与动物健康的疫苗接种策略的重要性，为同一健康（One Health）理念提供了实证支撑。