Dengue epidemiology in selected endemic countries: factors influencing expansion factors as estimates of underreporting

Abstract

Abstractobjective Dengue fever is globally considered underestimated. This study provides expansion factors (EFs) for dengue endemic selected countries and highlights critical issues in the use of EFs. results Cohort studies differed in case definition, laboratory test used and surveillance methods. The information on SEARO, PAHO and WPRO websites differed in terms of dengue epidemiological variables, population denominators and completeness. The highest incidence was reported by PAHO countries followed by WPRO and SEARO countries. EFs may vary for the different variables and denominators used for calculation. EFs were the highest in SEARO countries and lowest in PAHO countries. A trend for lower local EFs was observed.conclusions The use of EFs for quantifying dengue underreporting may be problematic due to lack of uniformity in reporting dengue both active and passive surveillance data. Quality dengue surveillance data are urgently needed for a better estimate of dengue disease burden and to measure the impact of preventive intervention.

Dengue virus serological prevalence and seroconversion rates in children and adults in Medellin, Colombia: implications for vaccine introduction

“…It could also indicate that in the study population, individuals were exposed to dengue at an older age rather than during the earlier years of life. This could also be attributed to the fact that the study was conducted after one of the biggest outbreaks to have occurred in Colombia (2010), probably increasing the odds of exposure to DENV of susceptible adults before the beginning of this study, increasing the overall seroprevalence and depleting susceptible people 14, 15, 16, 27, 28. This aspect is important at the time of dengue vaccine introduction 18, 19, 28, 29, 30.…”

“…Epidemic waves have been occurring every 3–4 years, with shorter inter-epidemic periods, and the incidence rate is up to 220 cases per 100 000 inhabitants per year 12, 13, 14, 15. Although there is an existing surveillance system in Colombia to collect and provide information about symptomatic cases, there is limited information on inapparent infection or mild cases of dengue in people who do not seek medical care 12, 15, 16…”

Disease Burden of Dengue in the Philippines: Adjusting for Underreporting by Comparing Active and Passive Dengue Surveillance in Punta Princesa, Cebu City

“…Using data from a dengue vaccine prospective cohort of children (2–14 years of age) in two study centers, Nealon and others71 compared incidence densities from active surveillance with incidence rates from the national passive surveillance system and obtained an EF of 11.5 (95% CL: 9.1–14.3). Toan and others40 estimated EFs for the Philippines as 15 and 14 episodes of dengue for each reported episode in 2007 and 2010, respectively, by comparing incidence rates from prospective community-based studies with estimated incidence at the country level. Their estimates were based on a follow-up study of young children (aged 2–15 months) in San Pablo, Laguna, in 2007–2008,72 and on a community-based enhanced surveillance program of children (2–14 years or age) in various cities in 2010–201173.…”

“…Misdiagnosis, particularly in countries with high incidence of other febrile illnesses,33–36 and underdiagnosis due to limited sensitivity and cost constraints of diagnostics tests may also contribute to underreporting 37,38. Additional sources of uncertainty in estimates of dengue incidence have been discussed elsewhere,39 and several studies have estimated average reporting rates of dengue episodes 3,40,41. Most studies have been limited to cohorts of children and/or adolescents 40.…”

“…Additional sources of uncertainty in estimates of dengue incidence have been discussed elsewhere,39 and several studies have estimated average reporting rates of dengue episodes 3,40,41. Most studies have been limited to cohorts of children and/or adolescents 40. Evidence from Puerto Rico and Brazil, both of which have a well-funded surveillance system, suggests that even fatal DENV infections may be underreported 42,43.…”