MMWR Morb Mortal Wkly Rep. 2021 Nov 5;70(44):1539-1544. doi: 10.15585/mmwr.mm7044e1.
Previous infection with SARS-CoV-2 (the virus that causes COVID-19) or COVID-19 vaccination can provide immunity and protection from subsequent SARS-CoV-2 infection and illness. CDC used data from the VISION Network* to examine hospitalizations in adults with COVID-19-like illness and compared the odds of receiving a positive SARS-CoV-2 test result, and thus having laboratory-confirmed COVID-19, between unvaccinated patients with a previous SARS-CoV-2 infection occurring 90-179 days before COVID-19-like illness hospitalization, and patients who were fully vaccinated with an mRNA COVID-19 vaccine 90-179 days before hospitalization with no previous documented SARS-CoV-2 infection. Hospitalized adults aged ≥18 years with COVID-19-like illness were included if they had received testing at least twice: once associated with a COVID-19-like illness hospitalization during January-September 2021 and at least once earlier (since February 1, 2020, and ≥14 days before that hospitalization). Among COVID-19-like illness hospitalizations in persons whose previous infection or vaccination occurred 90-179 days earlier, the odds of laboratory-confirmed COVID-19 (adjusted for sociodemographic and health characteristics) among unvaccinated, previously infected adults were higher than the odds among fully vaccinated recipients of an mRNA COVID-19 vaccine with no previous documented infection (adjusted odds ratio [aOR] = 5.49; 95% confidence interval [CI] = 2.75-10.99). These findings suggest that among hospitalized adults with COVID-19-like illness whose previous infection or vaccination occurred 90-179 days earlier, vaccine-induced immunity was more protective than infection-induced immunity against laboratory-confirmed COVID-19. All eligible persons should be vaccinated against COVID-19 as soon as possible, including unvaccinated persons previously infected with SARS-CoV-2.
先前感染过 SARS-CoV-2（导致 COVID-19 的病毒）或接种过 COVID-19 疫苗可提供免疫力，并防止随后感染 SARS-CoV-2 及患病。CDC 使用 VISION 网络*的数据，检查患有 COVID-19 样疾病的成年人的住院情况，并比较了无先前 SARS-CoV-2 感染史且在 COVID-19 样疾病住院前 90-179 天发生 SARS-CoV-2 感染的未接种患者与在住院前 90-179 天接受过 mRNA COVID-19 疫苗完全接种且无先前记录 SARS-CoV-2 感染的患者获得 SARS-CoV-2 检测阳性结果的几率，即实验室确诊 COVID-19 的几率。如果符合以下条件，则将年龄≥18 岁的患有 COVID-19 样疾病的住院成年人纳入研究：至少接受过两次检测：一次与 COVID-19 样疾病住院相关，发生在 2021 年 1 月至 9 月期间，另一次更早（自 2020 年 2 月 1 日起，且在该住院之前至少 14 天）。在先前感染或接种疫苗发生在 90-179 天前的 COVID-19 样疾病住院患者中，无先前记录感染史的完全接种 mRNA COVID-19 疫苗的接种者与未接种疫苗、先前感染 SARS-CoV-2 的成年人相比，实验室确诊 COVID-19 的几率（调整社会人口学和健康特征后）更高（调整后的优势比[aOR] = 5.49；95%置信区间[CI] = 2.75-10.99）。这些发现表明，在 COVID-19 样疾病住院的成年人中，先前感染或接种疫苗发生在 90-179 天前，与感染诱导的免疫力相比，疫苗诱导的免疫力对实验室确诊 COVID-19 更具保护作用。所有符合条件的人都应尽快接种 COVID-19 疫苗，包括先前感染过 SARS-CoV-2 的未接种人群。
