Impact of Home Environment Interventions on the Risk of Influenza-Associated ARI in Andean Children: Observations from a Prospective Household-Based Cohort Study

Abstract

BackgroundThe Respiratory Infections in Andean Peruvian Children (RESPIRA-PERU) study enrolled children who participated in a community-cluster randomized trial of improved stoves, solar water disinfection, and kitchen sinks (IHIP trial) and children from additional Andean households. We quantified the burden of influenza-associated acute respiratory illness (ARI) in this household-based cohort.MethodsFrom May 2009 to September 2011, we conducted active weekly ARI surveillance in 892 children age <3 years, of whom 272 (30.5%) had participated in the IHIP trial. We collected nasal swabs during ARI, tested for influenza and other respiratory viruses by RT-PCR, and determined influenza incidence and risk factors using mixed-effects regression models.ResultsThe overall incidence of influenza-associated ARI was 36.6/100 child-years; incidence of influenza A, B, and C was 20.5, 8.7, and 5.2/100 child-years, respectively. Influenza C was associated with fewer days of subjective fever (median 1 vs. 2) and malaise (median 0 vs. 2) compared to influenza A. Non-influenza ARI also resulted in fewer days of fever and malaise, and fewer healthcare visits than influenza A-associated ARI. Influenza incidence varied by calendar year (80% occurred in the 2010 season) and IHIP trial participation. Among households that participated in the IHIP trial, influenza-associated ARI incidence was significantly lower in intervention than in control households (RR 0.40, 95% CI: 0.20–0.82).ConclusionsInfluenza burden is high among Andean children. ARI associated with influenza A and B had longer symptom duration and higher healthcare utilization than influenza C-associated ARI or non-influenza ARI. Environmental community interventions may reduce influenza morbidity.

Spatial and Temporal Spread of Acute Viral Respiratory Infections in Young Children Living in High-altitude Rural Communities

“…Similarly, we did not include altitude in our estimations. Previous studies conducted in the same population have reported higher rates of influenza infection occurring between 2,322– 2,641 meters above sea level compared with higher altitudes 9 . Similarly, higher rates of RSV were noted between 2,626– 2,865 meters above sea level compared with higher altitudes 30 .…”

“…Few studies have characterized the burden of viral ARI among children living in high altitude settings, such as the Peruvian Andes. Our previous studies conducted in this region 6,8,9 reported an overall ARI incidence rate of 62 [95% CI: 59–65] per 100 child-years 8 . The incidence rate of influenza ARI was 37 per 100 child-years, which is as high or higher than rates from other low and middle income counties 9 , such as Bangladesh and Vietnam 7,10 .…”

“…In certain high altitude regions, inclement weather may drive people indoors for longer periods of time 11 , increasing the length of the time individuals are exposed to indoor pollution 9 and/or social contacts with patients with ARI 12,13 . We have previously reported that in rural highland communities of the Peruvian Andes, social contacts that could facilitate the transmission of infections were very frequent and physical contacts appeared to be higher than in some other developing counties 14 .…”

Emerging Respiratory Viruses in Children

“…24 Recent studies using molecular detection have suggested that influenza C is more frequent in children than previously recognized. 24,26,[28][29][30][31] Clinical Symptoms…”

“…31 Influenza C has been associated with fewer febrile days and less health care utilization than influenza A or B, suggesting a milder pathogen. 29 Like other influenza types, influenza C has been associated with encephalopathy. 32…”