Abstract：
It is unclear how the risk of post-covid symptoms evolved during the pandemic, especially before the spread of Severe Acute Respiratory Syndrome Coronavirus 2 variants and the availability of vaccines. We used modified Poisson regressions to compare the risk of six-month post-covid symptoms and their associated risk factors according to the period of first acute covid: during the French first (March-May 2020) or second (September-November 2020) wave. Non-response weights and multiple imputation were used to handle missing data. Among participants aged 15 or more in a national population-based cohort, the risk of post-covid symptoms was 14.6% (95% CI: 13.9%, 15.3%) in March-May 2020, versus 7.0% (95% CI: 6.3%, 7.7%) in September-November 2020 (adjusted RR: 1.36, 95% CI: 1.20, 1.55). For both periods, the risk was higher in the presence of baseline physical condition(s), and it increased with the number of acute symptoms. During the first wave, the risk was also higher for women, in the presence of baseline mental condition(s), and it varied with educational level. In France in 2020, the risk of six-month post-covid symptoms was higher during the first than the second wave. This difference was observed before the spread of variants and the availability of vaccines.
摘要：
目前还不清楚流感大流行期间感染后症状的风险是如何演变的，特别是在严重急性呼吸系统综合症冠状病毒2变种的传播和疫苗的供应之前。我们使用改良的Poisson回归分析，根据第一次急性covid期间：法国第一次（2020年3月至5月）或第二次（2020年9月至11月），比较covid症状后六个月的风险及其相关风险因素。无响应权重和多重归因用于处理缺失数据。在国家基于人口的队列中，年龄在15岁或以上的参与者中，covid后症状的风险为14.6%(95%CI：13.9%，15.3%），2020年3月至5月为7.0%（95%CI：6.3%，7.7%），2020年9月-11月（调整后RR：1.36，95%CI：1.20，1.55）。对于这两个时期，在存在基线身体状况的情况下，风险更高，随着急性症状的增加。在第一波中，女性的风险也更高，在存在基线精神状态的情况下，它随教育水平而变化。在2020年的法国，第一波感染后六个月症状的风险高于第二波。在变体的传播和疫苗的可用性之前观察到这种差异。
