Design and initiation of a study to assess the direct and indirect effects of influenza vaccine given to children in rural India

Abstract

The burden of disease due to influenza is not well characterized for children in developing countries and the effectiveness of available influenza vaccines in lower resource settings has not been established. We initiated a prospective, longitudinal, phase IV, household-randomized, controlled, observer-blinded three year study (2009)(2010)(2011) in a rural community of India to measure the total and indirect household protective effects of immunizing children ages 6 months through 10 years with seasonal inactivated trivalent influenza vaccine (TIV) or a control vaccine (n = 3697). Active weekly surveillance was conducted year round with home visits for identification of febrile acute respiratory illness (FARI) conducted for all vaccine recipients and household members (n = 18,220). Nasal and throat swabs were collected from each FARI episode for influenza detection by real-time reverse transcription polymerase chain reaction. The primary outcome was reduction in laboratory confirmed influenza infections in the influenza vaccine versus control vaccine group, with secondary outcome assessing indirect effects among the entire study population. This report describes the study site, cluster study design, choice of study and control vaccines, and the initial enrollment in the study.

Incidence of symptomatic A(H1N1)pdm09 influenza during the pandemic and post-pandemic periods in a rural Indian community

“…Second, the overall influenza rates reported here may have been influenced by the fact that almost one-half of the children had received influenza vaccine from November 2009 to January 2010. 8 While the 2009 seasonal vaccine did not contain pandemic virus, recent studies have shown that prior infection with influenza A (H1N1), 12,13 or immunization with seasonal live attenuated influenza vaccine, may confer some cross-protection against the A/(H1N1)pdm09 virus. 14,15 Thus, we believe that the current study likely represents a minimal estimate of IRs for pandemic influenza.…”

“…It is plausible that the true incidence of A(H1N1)pdm09 may even be greater than the IR we reported for the pandemic period, since the initial pandemic influenza peak was observed during August 2009 in this region but was not captured because the study reported here had not yet begun. 8 …”

“…8 The vaccine trial is an ongoing prospective, longitudinal, phase IV, household-randomized, controlled, observer-blinded 3-year study (2009–2011) designed to measure the direct and indirect protective effects of immunizing children aged 6 months through 10 years with seasonal inactivated trivalent influenza vaccine (TIV) or a control vaccine (http://www.ClinicalTrials.gov, NCT00934245). 8 The 2009 northern hemisphere influenza vaccine administered in December 2009 through January 2010 included strains: A/Brisbane/59/2007 (H1N1), A/Brisbane/10/2007 (H3N2), and B/Brisbane/60/2008. Pandemic virus was not a component of this vaccine.…”

“…Population-based weekly active surveillance implemented soon after the emergence of pandemic influenza in a rural community in India 8 provided an opportunity to determine the overall incidence of A(H1N1)pdm09 during the first influenza pandemic of the 21 st century. This information on magnitude, age distribution, and seasonality of A(H1N1)pdm09 will be useful for modeling disease burden, advocacy, and health system planning.…”

Cost effectiveness of influenza vaccination for specific populations in Iran

“…For the healthcare workers group, we calculated a pooled estimate of vaccine efficacy amongst 10 studies [8][9][10][11][12][13][14][15][16][17] for healthy adults aged 18-49 and results of the meta-analysis showed that pooled estimate of vaccine efficacy was equal to 66% (CI: 60-72) and there was heterogeneity between the results of the studies (Q = 13.69, P = 0.250). Regarding the school-age children, 2 studies [18,19] were included and pooled estimate of the vaccine efficacy was 64% (CI: 51-76).…”