MMWR Morb Mortal Wkly Rep. 2022 Feb 25;71(8):299-305. doi: 10.15585/mmwr.mm7108a4.
During December 2021, the United States experienced a surge in COVID-19 cases, coinciding with predominance of the SARS-CoV-2 B.1.1.529 (Omicron) variant (1). During this surge, the National Football League (NFL) and NFL Players Association (NFLPA) adjusted their protocols for test-to-release from COVID-19 isolation on December 16, 2021, based on analytic assessments of their 2021 test-to-release data. Fully vaccinated* persons with COVID-19 were permitted to return to work once they were asymptomatic or fever-free and experiencing improving symptoms for ≥24 hours, and after two negative or high cycle-threshold (Ct) results (Ct≥35) from either of two reverse transcription-polymerase chain reaction (RT-PCR) tests (2). This report describes data from NFL's SARS-CoV-2 testing program (3) and time to first negative or Ct≥35 result based on serial COVID-19 patient testing during isolation. Among this occupational cohort of 173 fully vaccinated adults with confirmed COVID-19 during December 14-19, 2021, a period of Omicron variant predominance, 46% received negative test results or had a subsequent RT-PCR test result with a Ct≥35 by day 6 postdiagnosis (i.e., concluding 5 days of isolation) and 84% before day 10. The proportion of persons with positive test results decreased with time, with approximately one half receiving positive RT-PCR test results after postdiagnosis day 5. Although this test result does not necessarily mean these persons are infectious (RT-PCR tests might continue to return positive results long after an initial positive result) (4), these findings indicate that persons with COVID-19 should continue taking precautions, including correct and consistent mask use, for a full 10 days after symptom onset or initial positive test result if they are asymptomatic.
2021 年 12 月期间,美国 COVID-19 病例激增,与 SARS-CoV-2 B.1.1.529(奥密克戎)变异株的流行相吻合(1)。在这一波疫情中,美国国家橄榄球联盟(NFL)和 NFL 球员协会(NFLPA)根据他们 2021 年的测试后释放数据的分析评估,于 2021 年 12 月 16 日调整了 COVID-19 隔离期的检测后释放协议(2)。完全接种疫苗*的 COVID-19 患者一旦无症状或退烧且症状持续改善超过 24 小时,并且两次从两次逆转录-聚合酶链反应(RT-PCR)检测(2)中获得阴性或高循环阈值(Ct)结果(Ct≥35)后,即可返回工作岗位。本报告描述了 NFL 的 SARS-CoV-2 检测计划(3)和基于隔离期间 COVID-19 患者检测的首次阴性或 Ct≥35 结果的时间。在 2021 年 12 月 14 日至 19 日期间,在奥密克戎变异株流行期间,173 名完全接种疫苗的成年人中,有 173 名成年人被确诊患有 COVID-19,其中 46%在诊断后第 6 天(即隔离期结束前 5 天)获得阴性检测结果或随后的 RT-PCR 检测结果为 Ct≥35,84%在第 10 天前获得阴性检测结果。随着时间的推移,阳性检测结果的比例下降,大约一半的人在诊断后第 5 天收到阳性 RT-PCR 检测结果。尽管该检测结果并不一定意味着这些人具有传染性(RT-PCR 检测可能在最初阳性结果后很长时间内继续返回阳性结果)(4),但这些发现表明,如果 COVID-19 患者无症状,他们应在症状出现或首次检测阳性后继续采取预防措施,包括正确和一致地佩戴口罩,共 10 天。