Infants aged <6 months are not eligible for COVID-19 vaccination. Vaccination during pregnancy has been associated with protection against infant COVID-19-related hospitalization. The Overcoming ...COVID-19 Network conducted a case-control study during March 9, 2022-May 31, 2023, to evaluate the effectiveness of maternal receipt of a COVID-19 vaccine dose (vaccine effectiveness VE) during pregnancy against COVID-19-related hospitalization in infants aged <6 months and a subset of infants aged <3 months. VE was calculated as (1 - adjusted odds ratio) x 100% among all infants aged <6 months and <3 months. Case-patients (infants hospitalized for COVID-19 outside of birth hospitalization and who had a positive SARS-CoV-2 test result) and control patients (infants hospitalized for COVID-19-like illness with a negative SARS-CoV-2 test result) were compared. Odds ratios were determined using multivariable logistic regression, comparing the odds of receipt of a maternal COVID-19 vaccine dose (completion of a 2-dose vaccination series or a third or higher dose) during pregnancy with maternal nonvaccination between case- and control patients. VE of maternal vaccination during pregnancy against COVID-19-related hospitalization was 35% (95% CI = 15%-51%) among infants aged <6 months and 54% (95% CI = 32%-68%) among infants aged <3 months. Intensive care unit admissions occurred in 23% of all case-patients, and invasive mechanical ventilation was more common among infants of unvaccinated (9%) compared with vaccinated mothers (1%) (p = 0.02). Maternal vaccination during pregnancy provides some protection against COVID-19-related hospitalizations among infants, particularly those aged <3 months. Expectant mothers should remain current with COVID-19 vaccination to protect themselves and their infants from hospitalization and severe outcomes associated with COVID-19.
Abstract
Background
Although antiviral therapy is recommended for hospitalized patients with suspected or confirmed influenza, clinicians often rely on test results to determine management. Rapid ...influenza diagnostic tests (RIDTs) have suboptimal sensitivity; use of molecular assays may improve care. We evaluated clinical influenza testing and antiviral treatment practices in hospitalized children.
Methods
Children aged <18 years with acute respiratory illness (ARI) were enrolled through active surveillance at 7 hospitals in the New Vaccine Surveillance Network between November 2015 and June 30, 2016; analysis was restricted to the influenza season. Preliminary data were analyzed for children who had clinical influenza diagnostic testing with a rapid influenza diagnostic test or molecular assay on nasopharyngeal or nasal swabs or nasal washes. Children who had received antivirals prior to hospitalization were excluded.
Results
Of 2267 children, 1165 (51%) had clinical diagnostic testing on upper respiratory samples: 276 (24%) by RIDT alone, 780 (67%) by molecular testing alone, and 109 (9%) by both. The use of molecular testing alone varied by site, from 10% to 100% of samples tested. Of 116 (10%) children testing positive for influenza, 60 (52%) were treated; by site, treatment of children positive for influenza ranged from 25% to 83%. Antiviral treatment was given to 16/20 (80%) of those admitted ≤2 days from symptom onset vs. 44/96 (46%) children admitted >2 days after onset. Among 94 children tested by one method who were positive, >80% had samples collected in the emergency department or on day of admission, and 47 started treatment (Figure, A): 16/37 (43%) and 31/57 (54%) were treated when tested by RIDT alone and molecular testing alone, respectively. Of those positive children treated, 7/16 (44%) tested by RIDT vs. 22/31 (71%) by molecular testing started treatment on the day of testing (Figure, B).
Conclusion
Half of hospitalized children with ARI who tested positive for influenza received antiviral treatment. Although there was high variability in testing and treatment by site, in positive patients who were treated the use of molecular testing appeared to be associated with prompt antiviral therapy. Understanding clinician reasons for relatively low treatment overall will require further investigation.
Disclosures
J. Englund, Gilead: Consultant and Investigator, Research support Chimerix: Investigator, Research support Alios: Investigator, Research support Novavax: Investigator, Research support MedImmune: Investigator, Research support GlaxoSmithKline: Investigator, Research support N. B. Halasa, sanofi pasteur: Research Contractor, Research support Astra Zeneca: Research Contractor, Grant recipient
Pediatric COVID-19 vaccination is effective in preventing COVID-19-related hospitalization, but duration of protection of the original monovalent vaccine during SARS-CoV-2 Omicron predominance merits ...evaluation, particularly given low coverage with updated COVID-19 vaccines. During December 19, 2021-October 29, 2023, the Overcoming COVID-19 Network evaluated vaccine effectiveness (VE) of ≥2 original monovalent COVID-19 mRNA vaccine doses against COVID-19-related hospitalization and critical illness among U.S. children and adolescents aged 5-18 years, using a case-control design. Too few children and adolescents received bivalent or updated monovalent vaccines to separately evaluate their effectiveness. Most case-patients (persons with a positive SARS-CoV-2 test result) were unvaccinated, despite the high frequency of reported underlying conditions associated with severe COVID-19. VE of the original monovalent vaccine against COVID-19-related hospitalizations was 52% (95% CI = 33%-66%) when the most recent dose was administered <120 days before hospitalization and 19% (95% CI = 2%-32%) if the interval was 120-364 days. VE of the original monovalent vaccine against COVID-19-related hospitalization was 31% (95% CI = 18%-43%) if the last dose was received any time within the previous year. VE against critical COVID-19-related illness, defined as receipt of noninvasive or invasive mechanical ventilation, vasoactive infusions, extracorporeal membrane oxygenation, and illness resulting in death, was 57% (95% CI = 21%-76%) when the most recent dose was received <120 days before hospitalization, 25% (95% CI = -9% to 49%) if it was received 120-364 days before hospitalization, and 38% (95% CI = 15%-55%) if the last dose was received any time within the previous year. VE was similar after excluding children and adolescents with documented immunocompromising conditions. Because of the low frequency of children who received updated COVID-19 vaccines and waning effectiveness of original monovalent doses, these data support CDC recommendations that all children and adolescents receive updated COVID-19 vaccines to protect against severe COVID-19.
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