Prospective observational cohort study with serial viral culture, rapid antigen detection test (RADT) and reverse transcription polymerase chain reaction (RT-PCR) on nasopharyngeal specimens of healthcare workers with COVID-19. The primary outcome was viral culture positivity as indicative of infectivity. Predictors of loss of infectivity were determined using multivariate regression model. The performance of the US Centers for Disease Control and Prevention (CDC) criteria (fever resolution, symptom improvement, and negative RADT) to predict loss of infectivity was also investigated.
In total, 121 participants (91 female [79.3%]; average age, 40 years) were enrolled. Most (n = 107, 88.4%) had received ≥3 severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccine doses, and 20 (16.5%) had COVID-19 previously. Viral culture positivity decreased from 71.9% (87/121) on day 5 of infection to 18.2% (22/121) on day 10. Participants with recurrent COVID-19 had a lower likelihood of infectivity than those with primary COVID-19 at each follow-up (day 5 odds ratio [OR], 0.14; P < .001]; day 7 OR, 0.04; P = .003]) and were all non-infective by day 10 (P = .02). Independent predictors of infectivity included prior COVID-19 (adjusted OR [aOR] on day 5, 0.005; P = .003), an RT-PCR cycle threshold [Ct] value <23 (aOR on day 5, 22.75; P < .001) but not symptom improvement or RADT result.The CDC criteria would identify 36% (24/67) of all non-infectious individuals on day 7. However, 17% (5/29) of those meeting all the criteria had a positive viral culture.
Infectivity of recurrent COVID-19 is shorter than primary infections. Loss of infectivity algorithms could be optimized.
方法:采用连续病毒培养的前瞻性观察性队列研究,COVID-19医护人员鼻咽标本的快速抗原检测(RADT)和RT-PCR。主要结果是病毒培养阳性作为感染性的指示。使用多元回归模型确定感染性丧失的预测因子。美国CDC标准的表现(发烧分辨率,还研究了症状改善和RADT阴性)以预测感染性丧失。
结果:121名参与者(91名女性[79.3%];平均年龄,40年)注册。大多数(n=107,88.4%)接受了≥3次SARS-CoV-2疫苗剂量,20人(16.5%)以前患有COVID-19。病毒培养阳性从感染第5天的71.9%(87/121)下降到第10天的18.2%(22/121)。在每次随访中,复发COVID-19的参与者感染的可能性低于原发性COVID-19的参与者(第5天OR,0.14;p<0.001];第7天或,0.04;p=0.003]),并且在第10天都是非感染性的(p=0.02)。感染性的独立预测因子包括先前的COVID-19(第5天调整的OR[aOR],0.005;p=0.003),RT-PCRCt值<23(第5天的aOR,22.75;p<0.001),但不是症状改善或RADT结果。CDC标准将在第7天鉴定所有非传染性个体的36%(24/67)。然而,满足所有标准的人中有17%(5/29)具有阳性病毒培养物。
结论:复发性COVID-19的传染性短于原发感染。感染性丧失算法可以被优化。