Some individuals experience prolonged illness after acute coronavirus disease 2019 (COVID-19). We assessed whether pre-infection symptoms affected post-acute COVID illness duration.

Survival analysis was performed in adults (n=23 452) with community-managed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection prospectively self-logging data through the ZOE COVID Symptom Study app, at least weekly, from 8 weeks before to 12 weeks after COVID-19 onset, conditioned on presence versus absence of baseline symptoms (4–8 weeks before COVID-19). A case–control study was performed in 1350 individuals with long illness (≥8 weeks, including 906 individuals (67.1%) with illness ≥12 weeks), matched 1:1 (for age, sex, body mass index, testing week, prior infection, vaccination, smoking, index of multiple deprivation) with 1350 individuals with short illness (<4 weeks). Baseline symptoms were compared between the two groups, and against post-COVID symptoms.

Individuals reporting baseline symptoms had longer COVID-related symptom duration (median 15 days versus 10 days for individuals without baseline symptoms) with baseline fatigue nearly doubling duration. Two-thirds (910 (67.4%) of 1350) of individuals with long illness were asymptomatic beforehand. However, 440 (32.6%) had baseline symptoms, versus 255 (18.9%) of 1350 individuals with short illness (p<0.0001). Baseline symptoms doubled the odds ratio for long illness (2.14, 95% CI 1.78–2.57). Prior comorbidities were more common in individuals with long versus short illness. In individuals with long illness, baseline symptomatic (versus asymptomatic) individuals were more likely to be female, younger, and have prior comorbidities; and baseline and post-acute symptoms, and symptom burden, correlated strongly.

Individuals experiencing symptoms before COVID-19 had longer illness duration and increased odds of long illness. However, many individuals with long illness were well before SARS-CoV-2 infection.

有些人在 2019 年急性冠状病毒病 (COVID-19) 后会长期患病。我们评估了感染前症状是否影响急性新冠病毒病程。

对社区管理的严重急性呼吸综合征冠状病毒 2 (SARS-CoV-2) 感染的成年人 (n=23 452) 进行生存分析，通过 ZOE COVID 症状研究应用程序前瞻性地自我记录数据，从 8 周起至少每周一次COVID-19 发病前至 12 周后，以是否存在基线症状为条件（COVID-19 前 4-8 周）。对 1350 名长期患病（≥8 周，其中 906 名（67.1%）患病≥12 周）的个体进行了病例对照研究，1:1 匹配（年龄、性别、体重指数、检测周数、之前感染、疫苗接种、吸烟、多重剥夺指数），1350 名短期患病者（<4 周）。比较了两组之间的基线症状以及新冠肺炎后的症状。

报告基线症状的个体与新冠病毒相关的症状持续时间较长（中位数为 15 天，而没有基线症状的个体为 10 天），基线疲劳持续时间几乎加倍。三分之二（1350 名长期患病者中的 910 名（67.4%））事先没有症状。然而，440 人 (32.6%) 有基线症状，而1350 名个体中有 255 人 (18.9%) 患有短期疾病（p<0 id=9>与短期疾病）。在长期患病个体中，基线有症状（与无症状）个体的比例更高可能是女性，更年轻，并且有既往合并症；并且基线和急性后症状以及症状负担密切相关。

在 COVID-19 之前出现症状的个体病程较长，且长期患病的几率较高。然而，许多长期患病的人早在感染 SARS-CoV-2 之前就已患病。