PT  - JOURNAL ARTICLE
AU  - Campbell, Angela P.
AU  - Ogokeh, Constance
AU  - Lively, Joana Y.
AU  - Staat, Mary A.
AU  - Selvarangan, Rangaraj
AU  - Halasa, Natasha B.
AU  - Englund, Janet A.
AU  - Boom, Julie A.
AU  - Weinberg, Geoffrey A.
AU  - Williams, John V.
AU  - McNeal, Monica
AU  - Harrison, Christopher J.
AU  - Stewart, Laura S.
AU  - Klein, Eileen J.
AU  - Sahni, Leila C.
AU  - Szilagyi, Peter G.
AU  - Michaels, Marian G.
AU  - Hickey, Robert W.
AU  - Moffat, Mary E.
AU  - Pahud, Barbara A.
AU  - Schuster, Jennifer E.
AU  - Weddle, Gina M.
AU  - Rha, Brian
AU  - Fry, Alicia M.
AU  - Patel, Manish
TI  - Vaccine Effectiveness Against Pediatric Influenza Hospitalizations and Emergency Visits
AID  - 10.1542/peds.2020-1368
DP  - 2020 Nov 01
TA  - Pediatrics
PG  - e20201368
VI  - 146
IP  - 5
4099  - http://pediatrics.aappublications.org/content/146/5/e20201368.short
4100  - http://pediatrics.aappublications.org/content/146/5/e20201368.full
SO  - Pediatrics2020 Nov 01; 146
AB  - BACKGROUND: Influenza A(H1N1)pdm09 viruses initially predominated during the US 2018–2019 season, with antigenically drifted influenza A(H3N2) viruses peaking later. We estimated vaccine effectiveness (VE) against laboratory-confirmed influenza-associated hospitalizations and emergency department (ED) visits among children in the New Vaccine Surveillance Network.METHODS: We tested children 6 months to 17 years with acute respiratory illness for influenza using molecular assays at 7 pediatric hospitals (ED patients <5 years at 3 sites). Vaccination status sources were parental report, state immunization information systems and/or provider records for inpatients, and parental report alone for ED patients. We estimated VE using a test-negative design, comparing odds of vaccination among children testing positive versus negative for influenza using multivariable logistic regression.RESULTS: Of 1792 inpatients, 226 (13%) were influenza-positive: 47% for influenza A(H3N2), 36% for A(H1N1)pdm09, 9% for A (not subtyped), and 7% for B viruses. Among 1944 ED children, 420 (22%) were influenza-positive: 48% for A(H3N2), 35% for A(H1N1)pdm09, 11% for A (not subtyped), and 5% for B viruses. VE was 41% (95% confidence interval [CI], 20% to 56%) against any influenza-related hospitalizations, 41% (95% CI, 11% to 61%) for A(H3N2), and 47% (95% CI, 16% to 67%) for A(H1N1)pdm09. VE was 51% (95% CI, 38% to 62%) against any influenza-related ED visits, 39% (95% CI, 15% to 56%) against A(H3N2), and 61% (95% CI, 44% to 73%) against A(H1N1)pdm09.CONCLUSIONS: The 2018–2019 influenza vaccine reduced pediatric influenza A-associated hospitalizations and ED visits by 40% to 60%, despite circulation of a drifted A(H3N2) clade.