Pediatrics: Live Attenuated and Inactivated Influenza Vaccine Effectiveness

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[h=1]Live Attenuated and Inactivated Influenza Vaccine Effectiveness[/h] Jessie R. Chung, Brendan Flannery, Christopher S. Ambrose, Rodolfo E. B?gu?, Herve Caspard, Laurie DeMarcus, Ashley L. Fowlkes, Geeta Kersellius, Andrea Steffens, Alicia M. Fry, for the Influenza Clinical Investigation for Children Study Team, the Influenza Incidence Surveillance Project, the US Influenza Vaccine Effectiveness Network


[h=2]Abstract[/h] BACKGROUND: Researchers in observational studies of vaccine effectiveness (VE) in which they compared quadrivalent live attenuated vaccine (LAIV4) and inactivated influenza vaccine (IIV) among children and adolescents have shown inconsistent results, and the studies have been limited by small samples.

METHODS: We combined data from 5 US studies from 2013?2014 through 2015?2016 to compare the VE of LAIV4 and IIV against medically attended, laboratory-confirmed influenza among patients aged 2 to 17 years by influenza season, subtype, age group, and prior vaccination status. The VE of IIV or LAIV4 was calculated as 100% ? (1 − odds ratio), comparing the odds of vaccination among patients who were influenza-positive to patients who were influenza-negative from adjusted logistic regression models. Relative effectiveness was defined as the odds of influenza comparingLAIV4 and IIV recipients.

RESULTS: Of 17 173 patients aged 2 to 17 years, 4579 received IIV, 1979 received LAIV4, and 10 615 were unvaccinated. Against influenza A/H1N1pdm09, VE was 67% (95% confidence interval [CI]: 62% to 72%) for IIV and 20% (95% CI: −6% to 39%) for LAIV4. Results were similar when stratified by vaccination in the previous season. LAIV4 recipients had significantly higher odds of influenza A/H1N1pdm09 compared with IIV recipients (odds ratio 2.66; 95% CI: 2.06 to 3.44). LAIV4 and IIV had similar effectiveness against influenza A/H3N2 and B. Our overall findings were consistent when stratified by influenza season and age group.

CONCLUSIONS: From this pooled individual patient?level data analysis, we found reduced effectiveness of LAIV4 against influenza A/H1N1pdm09 compared with IIV, which is consistent with published results from the individual studies included.

• Accepted September 27, 2018.

• Copyright ? 2019 by the American Academy of Pediatrics

http://pediatrics.aappublications.org/content/early/2019/01/03/peds.2018-2094

 

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Pediatrics
January 2019
Commentary


[h=1]Live Attenuated Influenza Vaccine: Will the Phoenix Rise Again?[/h] Pedro A. Piedra





The live attenuated influenza vaccine (LAIV) (FluMist) has undergone a roller coaster journey since its licensure in 2003 for eligible individuals 5 to 49 years of age and subsequent expansion to children 2 to 4 years of age in 2007. LAIV was the first new influenza vaccine approved in the United States since the introduction of the inactivated influenza vaccine (IIV) developed in the 1940s. Authors of studies performed before the influenza A/H1N1 2009 pandemic (A/H1N1pdm09) suggested that LAIV was more efficacious than IIV in pediatric populations.[SUP]1[/SUP] The Advisory Committee on Immunization Practices (ACIP) from the Centers for Disease Control and Prevention recommended preferential use of the LAIV for eligible children 2 to 8 years of age in the 2014?2015 season, removed the preferential recommendation in the 2015?2016 season, and provided interim recommendation against its use during the 2016?2017 and 2017?2018 seasons because of observational studies suggesting effectiveness that would be lower than expected against the A/H1N1pdm09.[SUP]2[/SUP][SUP]?[/SUP][SUP]5[/SUP]
The study by Chung et al,[SUP]6[/SUP] ?Live Attenuated and Inactivated Influenza Vaccine Effectiveness? in this issue of Pediatrics is a meta-analysis from 5 observational programs conducted from 2013?2014 through 2015?2016 comparing vaccine effectiveness between live ?


http://pediatrics.aappublications.org/content/early/2019/01/03/peds.2018-3290