MMWR Morb Mortal Wkly Rep. 2021 Apr 2;70(13):495-500. doi: 10.15585/mmwr.mm7013e3.
Messenger RNA (mRNA) BNT162b2 (Pfizer-BioNTech) and mRNA-1273 (Moderna) COVID-19 vaccines have been shown to be effective in preventing symptomatic COVID-19 in randomized placebo-controlled Phase III trials (1,2); however, the benefits of these vaccines for preventing asymptomatic and symptomatic SARS-CoV-2 (the virus that causes COVID-19) infection, particularly when administered in real-world conditions, is less well understood. Using prospective cohorts of health care personnel, first responders, and other essential and frontline workers* in eight U.S. locations during December 14, 2020-March 13, 2021, CDC routinely tested for SARS-CoV-2 infections every week regardless of symptom status and at the onset of symptoms consistent with COVID-19-associated illness. Among 3,950 participants with no previous laboratory documentation of SARS-CoV-2 infection, 2,479 (62.8%) received both recommended mRNA doses and 477 (12.1%) received only one dose of mRNA vaccine. Among unvaccinated participants, 1.38 SARS-CoV-2 infections were confirmed by reverse transcription-polymerase chain reaction (RT-PCR) per 1,000 person-days. In contrast, among fully immunized (≥14 days after second dose) persons, 0.04 infections per 1,000 person-days were reported, and among partially immunized (≥14 days after first dose and before second dose) persons, 0.19 infections per 1,000 person-days were reported. Estimated mRNA vaccine effectiveness for prevention of infection, adjusted for study site, was 90% for full immunization and 80% for partial immunization. These findings indicate that authorized mRNA COVID-19 vaccines are effective for preventing SARS-CoV-2 infection, regardless of symptom status, among working-age adults in real-world conditions. COVID-19 vaccination is recommended for all eligible persons.
信使 RNA（mRNA）BNT162b2（辉瑞-生物科技）和 mRNA-1273（莫德纳）COVID-19 疫苗已在随机安慰剂对照 III 期试验中证明可有效预防有症状的 COVID-19（1,2）；然而，这些疫苗在预防无症状和有症状的 SARS-CoV-2（引起 COVID-19 的病毒）感染方面的益处，特别是在现实条件下，了解得较少。在美国 8 个地点的医疗保健人员、急救人员和其他必要和一线工作人员*的前瞻性队列中，CDC 于 2020 年 12 月 14 日至 2021 年 3 月 13 日期间，每周无论症状状态如何，以及出现符合 COVID-19 相关疾病的症状时，都定期进行 SARS-CoV-2 感染检测。在 3950 名无 SARS-CoV-2 感染实验室记录的参与者中，2479 名（62.8%）接受了推荐剂量的 mRNA 疫苗，477 名（12.1%）仅接受了一剂 mRNA 疫苗。在未接种疫苗的参与者中，每 1000 人天通过逆转录-聚合酶链反应（RT-PCR）确认了 1.38 例 SARS-CoV-2 感染。相比之下，在完全免疫（第二剂后≥14 天）人群中，每 1000 人天报告 0.04 例感染，在部分免疫（第一剂后≥14 天和第二剂前）人群中，每 1000 人天报告 0.19 例感染。调整研究地点后，mRNA 疫苗预防感染的估计有效性为完全免疫接种 90%，部分免疫接种 80%。这些发现表明，在现实条件下，授权的 mRNA COVID-19 疫苗对工作年龄成年人的 SARS-CoV-2 感染有效，无论症状状态如何。建议所有符合条件的人接种 COVID-19 疫苗。
