Vaccine Effectiveness Against Life-Threatening Influenza Illness in US Children.
Clin Infect Dis
; 75(2): 230-238, 2022 08 25.
Article
in En
| MEDLINE
| ID: mdl-35024795
BACKGROUND: Predominance of 2 antigenically drifted influenza viruses during the 2019-2020 season offered an opportunity to assess vaccine effectiveness against life-threatening pediatric influenza disease from vaccine-mismatched viruses in the United States. METHODS: We enrolled children aged <18 years admitted to the intensive care unit with acute respiratory infection across 17 hospitals. Respiratory specimens were tested using reverse-transcription polymerase chain reaction for influenza viruses and sequenced. Using a test-negative design, we estimated vaccine effectiveness comparing odds of vaccination in test-positive case patients vs test-negative controls, stratifying by age, virus type, and severity. Life-threating influenza included death or invasive mechanical ventilation, vasopressors, cardiopulmonary resuscitation, dialysis, or extracorporeal membrane oxygenation. RESULTS: We enrolled 159 critically ill influenza case-patients (70% ≤8 years; 51% A/H1N1pdm09 and 25% B-Victoria viruses) and 132 controls (69% were aged ≤8 years). Among 56 sequenced A/H1N1pdm09 viruses, 29 (52%) were vaccine-mismatched (A/H1N1pdm09/5A+156K) and 23 (41%) were vaccine-matched (A/H1N1pdm09/5A+187A,189E). Among sequenced B-lineage viruses, majority (30 of 31) were vaccine-mismatched. Effectiveness against critical influenza was 63% (95% confidence interval [CI], 38% to 78%) and similar by age. Effectiveness was 75% (95% CI, 49% to 88%) against life-threatening influenza vs 57% (95% CI, 24% to 76%) against non-life-threating influenza. Effectiveness was 78% (95% CI, 41% to 92%) against matched A(H1N1)pdm09 viruses, 47% (95% CI, -21% to 77%) against mismatched A(H1N1)pdm09 viruses, and 75% (95% CI, 37% to 90%) against mismatched B-Victoria viruses. CONCLUSIONS: During a season when vaccine-mismatched influenza viruses predominated, vaccination was associated with a reduced risk of critical and life-threatening influenza illness in children.
Key words
Full text:
1
Collection:
01-internacional
Health context:
1_ASSA2030
/
2_ODS3
/
6_ODS3_enfermedades_notrasmisibles
/
7_ODS3_muertes_prevenibles_nacidos_ninos
Database:
MEDLINE
Main subject:
Influenza Vaccines
/
Influenza, Human
/
Influenza A Virus, H1N1 Subtype
Type of study:
Observational_studies
/
Risk_factors_studies
Limits:
Child
/
Humans
Country/Region as subject:
America do norte
Language:
En
Journal:
Clin Infect Dis
Year:
2022
Document type:
Article