Effect of Vaccination on Preventing Influenza-Associated Hospitalizations Among Children During a Severe Season Associated With B/Victoria Viruses, 2019-2020.
Clin Infect Dis
; 73(4): e947-e954, 2021 08 16.
Article
in En
| MEDLINE
| ID: mdl-33502489
ABSTRACT
BACKGROUND:
The 2019-2020 influenza season was characterized by early onset with B/Victoria followed by A(H1N1)pdm09 viruses. Emergence of new B/Victoria viruses raised concerns about possible vaccine mismatch. We estimated vaccine effectiveness (VE) against influenza-associated hospitalizations and emergency department (ED) visits among children in the United States.METHODS:
We assessed VE among children aged 6 months-17 years with acute respiratory illness and ≤10 days of symptoms enrolled at 7 pediatric medical centers in the New Vaccine Surveillance Network. Combined midturbinate/throat swabs were tested for influenza virus using molecular assays. Vaccination history was collected from parental report, state immunization information systems, and/or provider records. We estimated VE from a test-negative design using logistic regression to compare odds of vaccination among children testing positive vs negative for influenza.RESULTS:
Among 2029 inpatients, 335 (17%) were influenza positive 37% with influenza B/Victoria alone and 44% with influenza A(H1N1)pdm09 alone. VE was 62% (95% confidence interval [CI], 52%-71%) for influenza-related hospitalizations, 54% (95% CI, 33%-69%) for B/Victoria viruses, and 64% (95% CI, 49%-75%) for A(H1N1)pdm09. Among 2102 ED patients, 671 (32%) were influenza positive 47% with influenza B/Victoria alone and 42% with influenza A(H1N1)pdm09 alone. VE was 56% (95% CI, 46%-65%) for an influenza-related ED visit, 55% (95% CI, 40%-66%) for B/Victoria viruses, and 53% (95% CI, 37%-65%) for A(H1N1)pdm09.CONCLUSIONS:
Influenza vaccination provided significant protection against laboratory-confirmed influenza-associated hospitalizations and ED visits associated with the 2 predominantly circulating influenza viruses among children, including against the emerging B/Victoria virus subclade.Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Influenza Vaccines
/
Herpesvirus 1, Cercopithecine
/
Influenza, Human
/
Influenza A Virus, H1N1 Subtype
Type of study:
Risk_factors_studies
Limits:
Child
/
Humans
/
Infant
Country/Region as subject:
America do norte
Language:
En
Journal:
Clin Infect Dis
Journal subject:
DOENCAS TRANSMISSIVEIS
Year:
2021
Type:
Article
Affiliation country:
United States