From the Division of Pediatric Infectious Diseases, Department of Pediatrics, Vanderbilt University Medical Center, Nashville (N.B.H.); the Covid-19 Response Team, Centers for Disease Control and Prevention (S.M.O., A.M.P., S.M.G., K.N.P., A.P.C., M.M.P.), the Center for Childhood Infections and Vaccines of Children's Healthcare of Atlanta and the Department of Pediatrics, Emory University School of Medicine (S.K.), and the Division of Critical Care Medicine, Department of Pediatrics, Emory University School of Medicine, Children's Healthcare of Atlanta (K.M.T.) - all in Atlanta; the Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati (M.A.S.), the Division of Pediatric Critical Care Medicine, Nationwide Children's Hospital, Columbus (K.E.B.), and the Division of Critical Care Medicine, Department of Pediatrics, Akron Children's Hospital, Akron (R.A.N.) - all in Ohio; the Department of Anesthesiology, Critical Care, and Pain Medicine, Boston Children's Hospital (M.M.N., A.G.R.), and the Departments of Anaesthesia and Pediatrics, Harvard Medical School (A.G.R.) - both in Boston; the Division of Infectious Diseases, Children's Hospital Los Angeles, and the Departments of Pediatrics and Molecular Microbiology and Immunology, University of Southern California, Los Angeles, Los Angeles (P.S.P.), the Division of Pediatric Hospital Medicine, UC San Diego-Rady Children's Hospital, San Diego (M.A.C.), the Department of Pediatrics, Divisions of Critical Care Medicine and Allergy, Immunology, and Bone Marrow Transplant, University of California, San Francisco, San Francisco (M.S.Z.), and the Division of Critical Care Medicine, UCSF Benioff Children's Hospital, Oakland (N.Z.C.) - all in California; the Department of Pediatrics, Baylor College of Medicine, Immunization Project, Texas Children's Hospital, Houston (J.A.B., L.C.S.); the Division of Critical Care Medicine, Department of Anesthesiology and Critical Care, Children's Hospital of Philadelphia, Philadelphia (K.C.); the Department of Pediatrics, Division of Infectious Diseases, University of Mississippi Medical Center, Jackson (C.V.H.); the Department of Pediatrics, Section of Critical Care Medicine, University of Colorado School of Medicine, and Children's Hospital Colorado, Aurora (A.B.M.); the Division of Critical Care Medicine, Department of Pediatrics, Northwestern University Feinberg School of Medicine, Ann and Robert H. Lurie Children's Hospital of Chicago, Chicago (B.M.C., K.N.M.); the Division of Pediatric Critical Care Medicine, Children's Hospital of Michigan, Central Michigan University, Detroit (S.M.H.), and the Division of Pediatric Critical Care Medicine, Department of Pediatrics, Mott Children's Hospital and University of Michigan, Ann Arbor (H.R.F.); the Section of Pediatric Critical Care, Department of Pediatrics, Arkansas Children's Hospital, Little Rock (K.I.); the Division of Pediatric Critical Care Medicine (E.H.M.), and the Department of Pediatrics (L.S.), Medical University of South Carolina, Charleston; the Department of Pediatrics, University of North Carolina at Chapel Hill Children's Hospital, Chapel Hill (S.P.S., T.C.W.); the Division of Pediatric Critical Care, Department of Pediatrics, Cooperman Barnabas Medical Center, Livingston, NJ (S.J.G.); the Division of Pediatric Infectious Diseases, Department of Pediatrics, Children's Mercy Kansas City, Kansas City, Missouri (J.E.S.); the Ryan White Center for Pediatric Infectious Disease and Global Health, Department of Pediatrics, Indiana University School of Medicine, Indianapolis (S.S.B.); the Department of Pediatrics, Division of Critical Care Medicine, University of Texas Southwestern, Children's Medical Center, Dallas (M.M.); the Division of Pediatric Critical Care, University of Minnesota Masonic Children's Hospital, Minneapolis (J.R.H.), and the Divisions of Pediatric Infectious Diseases and Pediatric Critical Care Medicine, Department of Pediatric and Adolescent Medicine, Mayo Clinic, Rochester (E.R.L.) - both in Minnesota; the Division of Pediatric Critical Care, Department of Pediatrics, University of Utah, Salt Lake City (H.C.); the Department of Pediatrics, Division of Cardiology, Louisiana State University Health Sciences Center and Children's Hospital of New Orleans, New Orleans (T.T.B.); the Division of Pediatric Critical Care, Department of Pediatrics, Children's Hospital and Medical Center, Omaha, NE (M.L.C.); and the Division of Pediatric Critical Care Medicine, Department of Pediatrics, University of Alabama at Birmingham, Birmingham (M.K.).
N Engl J Med. 2022 Jul 14;387(2):109-119. doi: 10.1056/NEJMoa2204399. Epub 2022 Jun 22.
Infants younger than 6 months of age are at high risk for complications of coronavirus disease 2019 (Covid-19) and are not eligible for vaccination. Transplacental transfer of antibodies against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) after maternal Covid-19 vaccination may confer protection against Covid-19 in infants.
We used a case-control test-negative design to assess the effectiveness of maternal vaccination during pregnancy against hospitalization for Covid-19 among infants younger than 6 months of age. Between July 1, 2021, and March 8, 2022, we enrolled infants hospitalized for Covid-19 (case infants) and infants hospitalized without Covid-19 (control infants) at 30 hospitals in 22 states. We estimated vaccine effectiveness by comparing the odds of full maternal vaccination (two doses of mRNA vaccine) among case infants and control infants during circulation of the B.1.617.2 (delta) variant (July 1, 2021, to December 18, 2021) and the B.1.1.259 (omicron) variant (December 19, 2021, to March 8, 2022).
A total of 537 case infants (181 of whom had been admitted to a hospital during the delta period and 356 during the omicron period; median age, 2 months) and 512 control infants were enrolled and included in the analyses; 16% of the case infants and 29% of the control infants had been born to mothers who had been fully vaccinated against Covid-19 during pregnancy. Among the case infants, 113 (21%) received intensive care (64 [12%] received mechanical ventilation or vasoactive infusions). Two case infants died from Covid-19; neither infant's mother had been vaccinated during pregnancy. The effectiveness of maternal vaccination against hospitalization for Covid-19 among infants was 52% (95% confidence interval [CI], 33 to 65) overall, 80% (95% CI, 60 to 90) during the delta period, and 38% (95% CI, 8 to 58) during the omicron period. Effectiveness was 69% (95% CI, 50 to 80) when maternal vaccination occurred after 20 weeks of pregnancy and 38% (95% CI, 3 to 60) during the first 20 weeks of pregnancy.
Maternal vaccination with two doses of mRNA vaccine was associated with a reduced risk of hospitalization for Covid-19, including for critical illness, among infants younger than 6 months of age. (Funded by the Centers for Disease Control and Prevention.).
6 月龄以下婴儿感染 2019 年冠状病毒病（COVID-19）并出现并发症的风险较高，且不符合疫苗接种条件。母体 COVID-19 疫苗接种后针对严重急性呼吸综合征冠状病毒 2（SARS-CoV-2）的抗体经胎盘转移，可能为婴儿提供针对 COVID-19 的保护。
我们使用病例对照检验阴性设计，评估母亲妊娠期间接种疫苗对 6 月龄以下婴儿因 COVID-19 住院的效果。在 2021 年 7 月 1 日至 2022 年 3 月 8 日期间，我们在 22 个州的 30 家医院中招募了因 COVID-19 住院的婴儿（病例婴儿）和未因 COVID-19 住院的婴儿（对照婴儿）。我们通过比较 B.1.617.2（德尔塔）变异株流行期间（2021 年 7 月 1 日至 2021 年 12 月 18 日）和 B.1.1.259（奥密克戎）变异株流行期间（2021 年 12 月 19 日至 2022 年 3 月 8 日）病例婴儿和对照婴儿中完全接受母体疫苗接种（两剂 mRNA 疫苗）的比例来估计疫苗的有效性。
共纳入 537 例病例婴儿（其中 181 例在德尔塔期住院，356 例在奥密克戎期住院；中位年龄为 2 个月）和 512 例对照婴儿，并纳入分析；16%的病例婴儿和 29%的对照婴儿的母亲在妊娠期间接受过 COVID-19 疫苗的完全接种。在病例婴儿中，有 113 例（21%）接受了重症监护（64 例[12%]接受机械通气或血管活性输注）。2 例病例婴儿死于 COVID-19；这两名婴儿的母亲均未在妊娠期间接种疫苗。总体而言，母体疫苗接种对 COVID-19 住院的有效性为 52%（95%置信区间[CI]，33 至 65），在德尔塔期为 80%（95%CI，60 至 90），在奥密克戎期为 38%（95%CI，8 至 58）。妊娠 20 周后接种疫苗的有效性为 69%（95%CI，50 至 80），妊娠前 20 周接种疫苗的有效性为 38%（95%CI，3 至 60）。
母体接受两剂 mRNA 疫苗接种与 6 月龄以下婴儿 COVID-19 住院风险降低相关，包括重症疾病住院风险降低。（由美国疾病控制与预防中心资助）。
