Blog
About

  • Record: found
  • Abstract: found
  • Article: found
Is Open Access

Efficacy of trivalent influenza vaccine against laboratory-confirmed influenza among young children in a randomized trial in Bangladesh

Read this article at

Bookmark
      There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

      Highlights

      •There is limited data on efficacy of yearly influenza vaccination in children aged <2 years.•Influenza vaccination was found to be safe and significantly reduced influenza in young children.•These findings support yearly influenza vaccination of young children.

      Abstract

      BackgroundFew trials have evaluated influenza vaccine efficacy (VE) in young children, a group particularly vulnerable to influenza complications. We aimed to estimate VE against influenza in children aged <2 years in Bangladesh; a subtropical setting, where influenza circulation can be irregular.MethodsChildren aged 6–23 months were enrolled 1:1 in a parallel, double-blind, randomized controlled trial of trivalent inactivated influenza vaccine (IIV3) versus inactivated polio vaccine (IPV); conducted August 2010–March 2014 in Dhaka, Bangladesh. Children received two pediatric doses of vaccine, one month apart, and were followed for one year for febrile and respiratory illness. Field assistants conducted weekly home-based, active surveillance and ill children were referred to the study clinic for clinical evaluation and nasopharyngeal wash specimen collection. Analysis included all children who received a first vaccine dose and compared yearly incidence of reverse transcription polymerase chain reaction (RT-PCR)-confirmed influenza between trial arms. The VE was estimated as 1 − (rate ratio of illness) × 100%, using unadjusted Poisson regression. The trial was registered with ClinicalTrials.gov, number NCT01319955.ResultsAcross four vaccination rounds, 4081 children were enrolled and randomized, contributing 2576 child-years of observation to the IIV3 arm and 2593 child-years to the IPV arm. Influenza incidence was 10 episodes/100 child-years in the IIV3 arm and 15 episodes/100 child-years in the IPV arm. Overall, the VE was 31% (95% confidence interval 18, 42%) against any RT-PCR-confirmed influenza. The VE varied by season, but was similar by influenza type/subtype and participant age and sex.ConclusionsVaccination of young children with IIV3 provided a significant reduction in laboratory-confirmed influenza; however, exploration of additional influenza vaccine strategies, such as adjuvanted vaccines or standard adult vaccine doses, is warranted to find more effective influenza vaccines for young children in low-income countries.

      Related collections

      Most cited references 28

      • Record: found
      • Abstract: found
      • Article: not found

      Global burden of respiratory infections due to seasonal influenza in young children: a systematic review and meta-analysis.

      The global burden of disease attributable to seasonal influenza virus in children is unknown. We aimed to estimate the global incidence of and mortality from lower respiratory infections associated with influenza in children younger than 5 years. We estimated the incidence of influenza episodes, influenza-associated acute lower respiratory infections (ALRI), and influenza-associated severe ALRI in children younger than 5 years, stratified by age, with data from a systematic review of studies published between Jan 1, 1995, and Oct 31, 2010, and 16 unpublished population-based studies. We applied these incidence estimates to global population estimates for 2008 to calculate estimates for that year. We estimated possible bounds for influenza-associated ALRI mortality by combining incidence estimates with case fatality ratios from hospital-based reports and identifying studies with population-based data for influenza seasonality and monthly ALRI mortality. We identified 43 suitable studies, with data for around 8 million children. We estimated that, in 2008, 90 million (95% CI 49-162 million) new cases of influenza (data from nine studies), 20 million (13-32 million) cases of influenza-associated ALRI (13% of all cases of paediatric ALRI; data from six studies), and 1 million (1-2 million) cases of influenza-associated severe ALRI (7% of cases of all severe paediatric ALRI; data from 39 studies) occurred worldwide in children younger than 5 years. We estimated there were 28,000-111,500 deaths in children younger than 5 years attributable to influenza-associated ALRI in 2008, with 99% of these deaths occurring in developing countries. Incidence and mortality varied substantially from year to year in any one setting. Influenza is a common pathogen identified in children with ALRI and results in a substantial burden on health services worldwide. Sufficient data to precisely estimate the role of influenza in childhood mortality from ALRI are not available. WHO; Bill & Melinda Gates Foundation. Copyright © 2011 Elsevier Ltd. All rights reserved.
        Bookmark
        • Record: found
        • Abstract: not found
        • Article: not found

        Vaccines against influenza WHO position paper – November 2012.

        (2012)
          Bookmark
          • Record: found
          • Abstract: found
          • Article: not found

          Effectiveness of seasonal influenza vaccines in the United States during a season with circulation of all three vaccine strains.

          Influenza vaccines may be reformulated annually because of antigenic drift in influenza viruses. However, the relationship between antigenic characteristics of circulating viruses and vaccine effectiveness (VE) is not well understood. We conducted an assessment of the effectiveness of US influenza vaccines during the 2010-2011 season. We performed a case-control study comparing vaccination histories between subjects with acute respiratory illness with positive real-time reverse transcription polymerase chain reaction for influenza and influenza test-negative controls. Subjects with acute respiratory illness of ≤7 days duration were enrolled in hospitals, emergency departments, or outpatient clinics in communities in 4 states. History of immunization with the 2010-2011 vaccine was ascertained from vaccine registries or medical records. Vaccine effectiveness was estimated in logistic regression models adjusted for study community, age, race, insurance status, enrollment site, and presence of a high-risk medical condition. A total of 1040 influenza-positive cases and 3717 influenza-negative controls were included from the influenza season, including 373 cases of influenza A(H1N1), 334 cases of influenza A(H3N2), and 333 cases of influenza B. Overall adjusted VE was 60% (95% confidence interval [CI], 53%-66%). Age-specific VE estimates ranged from 69% (95% CI, 56%-77%) in children aged 6 months-8 years to 38% (95% CI, -16% to 67%) in adults aged ≥65 years. The US 2010-2011 influenza vaccines were moderately effective in preventing medically attended influenza during a season when all 3 vaccine strains were antigenically similar to circulating viruses. Continued monitoring of influenza vaccines in all age groups is important, particularly as new vaccines are introduced.
            Bookmark

            Author and article information

            Affiliations
            [a ]Epidemic Intelligence Service, Centers for Disease Control and Prevention, Atlanta, GA, USA
            [b ]Influenza Division, Centers for Disease Control and Prevention, Atlanta, GA, USA
            [c ]Icddr,b, Dhaka, Bangladesh
            [d ]Stanford Medical School, Stanford, CA, USA
            [e ]Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
            Author notes
            [* ]Corresponding author at: Centers for Disease Control and Prevention, 1600 Clifton Rd. NE, MS A-32, Atlanta, GA 30329.Centers for Disease Control and Prevention1600 Clifton Rd. NEMS A-32AtlantaGA 30329 ydi8@ 123456cdc.gov
            [** ]Co-corresponding author at: Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe St., Baltimore, MD 21205.Johns Hopkins Bloomberg School of Public Health615 N. Wolfe St.BaltimoreMD 21205 wbrooks3@ 123456jhu.edu
            Contributors
            Journal
            Vaccine
            Vaccine
            Vaccine
            Elsevier Science
            0264-410X
            1873-2518
            15 December 2017
            15 December 2017
            : 35
            : 50
            : 6967-6976
            29100706
            5723570
            S0264-410X(17)31482-2
            10.1016/j.vaccine.2017.10.074

            This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).

            Categories
            Article

            Infectious disease & Microbiology

            children, clinical trial, vaccine, influenza

            Comments

            Comment on this article