Rapid assessment of Hib disease burden in Vietnam

Abstract

BackgroundSeveral countries have applied the Haemophilus influenzae type b (Hib) rapid assessment tool (RAT) to estimate the burden of Hib disease where resources for hospital- or population-based surveillance are limited. In Vietnam, we used the Hib RAT to estimate the burden of Hib pneumonia and meningitis prior to Hib vaccine introduction.MethodsLaboratory, hospitalization and mortality data were collected for the period January 2004 through December 2005 from five representative hospitals. Based on the WHO Hib RAT protocol, standardized MS Excel spreadsheets were completed to generate meningitis and pneumonia case and death figures.ResultsWe found 35 to 77 Hib meningitis deaths and 441 to 957 Hib pneumonia deaths among children < 5 years of age annually in Vietnam. Overall, the incidence of Hib meningitis was estimated at 18/100,000 (95% confidence interval, CI, 15.1-21.6). The estimated Hib meningitis incidence in children < 5 years age was higher in Ho Chi Minh City (22.5/100,000 [95% CI, 18.4-27.5]) compared to Hanoi (9.8/100,000 [95% CI, 6.5-14.8]). The Hib RAT suggests that there are a total of 883 to 1,915 cases of Hib meningitis and 4,414 to 9,574 cases of Hib pneumonia per year in Vietnam.ConclusionsIn Hanoi, the estimated incidence of Hib meningitis for children < 5 years of age was similar to that described in previous population-based studies of Hib meningitis conducted from 1999 through 2002. Results from the Hib RAT suggest that there is a substantial, yet unmeasured, disease burden associated with Hib pneumonia in Vietnamese children.

Cost-effectiveness of Haemophilus influenzae type b vaccine in Vietnam

“…In Vietnam, two epidemiologic studies estimated Hib disease burden before vaccine introduction. One study was a population-based surveillance and the other was a hospital-based surveillance [3, 12]. While both used appropriate case definitions and laboratory techniques, they failed to account for both missing cases and meningitis cases without lumbar puncture, so the reported incidence was likely underestimated.…”

“…Hib meningitis incidence was based on a retrospective study using the WHO Rapid Assessment Tool (RAT) [3]. We chose the RAT which reported a higher incidence estimate than that of a study conducted during 2000-2002 [12] as RAT estimates were more updated and representative.…”

“…Incidence of clinical pneumonia was estimated from hospital-based surveillance in Khanh Hoa during 2005- 2006 [13]. Because of the lack of hospital-based CFR data, we calculated CFR for treated pneumonia cases from the same RAT study [3]. …”

“…Hib can cause meningitis, pneumonia and other less frequent diseases, primarily in children less than five years [1, 2]. In Vietnam, the incidence of Hib meningitis was estimated to be 18/100,000 (95% confidence interval, 15.1-21.6) in children less than five years [3]. …”

Early indication for a reduced burden of radiologically confirmed pneumonia in children following the introduction of routine vaccination against Haemophilus influenzae type b in Nha Trang, Vietnam

“…An increasing body of evidence has been emerging that Hib substantially contributes to the burden of disease in Asia [13][14][15][16][17] and that the incidence and mortality associated with Hib in Southeast Asia are in fact similar to levels observed in many other parts of the world, in particular in the Americas [1]. This includes recent findings from Vietnam [18,19].…”