ABSTRACT
Background: Rotavirus is the main cause of severe gastroenteritis (GE) in children. Two vaccines currently available have proven efficacy against the predominant genotypes. Rotavirus genotypes vary both geographically and/or temporally. Genotype surveillance is important to monitor trends associated or not with vaccine use. Aim: To update information on rotavirus genotypes circulating in two main cities of Chile. Methodology: Between May 2009-March 2010, children < 5y of age receiving medical care for GE in two large hospitals were recruited; none of these children had received rotavirus vaccine previously. Epidemiological information was recorded in an ad-hoc form and stool samples were collected for rotavirus detection by a commercial ELISA. Genotyping was performed by semi-nested RT-PCR. Results: A total of 296/967 samples (31%) were positive for rotavirus, with a peak in November/ December mostly in children 7-24 months old (67%). G9P[8] was the predominant genotype (76%), followed for G1P[8] (6%) and G2P[4] (6%) in both cities. Conclusions: Rotavirus caused one third of GE requiring emergency room care and/or hospitalization, mostly in children within an age range susceptible to benefit from rotavirus vaccines. G9P[8], a genotype against which rotavirus vaccines have demonstrated high efficacy, was by far the most frequent rotavirus variant. Continued surveillance in Chile is crucial for providing background information on disease burden and strain diversity before the introduction of rotavirus vaccines.
Antecedentes: Rotavirus es la principal causa de gastroenteritis (GE) grave en niños. Actualmente se dispone de dos vacunas con eficacia demostrada contra los genotipos predominantes en el mundo. Los genotipos de rotavirus varían en el tiempo y de una región a otra. Es importante mantener la vigilancia de los genotipos circulantes para monitorizar las tendencias asociadas o no al uso de vacunas. Objetivo: Actualizar la información sobre genotipos de rotavirus circulantes en dos ciudades importantes de Chile (Santiago y Valparaíso). Metodología: Entre mayo 2009 y marzo 2010 se reclutaron niños bajo 5 años de edad con GE atendidos en dos hospitales; ninguno de ellos con historia previa de vacunación anti-rotavirus. Se registró información epidemiológica y se tomó muestra de deposición para detección de rotavirus mediante ELISA comercial. Se realizó genotipificación mediante RPC-TR semi-anidada. Resultados: Se detectó rotavirus en 296/967 muestras analizadas (31%), con un pico de frecuencia en noviembre/diciembre y afectando predominantemente al grupo de 7-24 meses de edad (67%). G9P[8] fue el genotipo predominante (76%), seguido por G1P[8] (6%) y G2P[4] (6%) en ambas ciudades. Conclusiones: Rotavirus causó un tercio de las GE en este grupo, afectando especialmente al grupo de edad que podría beneficiarse con la vacunación anti-rotavirus. G9P[8], una de las variantes contra las cuales las vacunas antirotavirus han demostrado alta eficacia, fue por lejos el genotipo más frecuente. Es necesario continuar la vigilancia en Chile de modo de conocer el impacto de la enfermedad y diversidad de variantes antes de la incorporación de una vacuna anti-rotavirus.
Subject(s)
Child, Preschool , Female , Humans , Infant , Male , Gastroenteritis/virology , Rotavirus Infections/virology , Rotavirus/genetics , Chile/epidemiology , Enzyme-Linked Immunosorbent Assay , Feces/virology , Genotype , Gastroenteritis/epidemiology , Hospitals, Public , Polymerase Chain Reaction , Reverse Transcriptase Polymerase Chain Reaction , RNA, Viral/genetics , Rotavirus Infections/epidemiology , SeasonsABSTRACT
Background: Rotavirus infections account every year in Chile, for approximately 53,000 emergency consultations and 8,000hospital admissions among children under three years of age. Aim: To estimate incidence rates of severe rotavirus gastroenteritis in children <3 years of age, living in the V and VIII Regions and to identify the predominant viral serotypes. Material and methods: A prospective hospital-based surveillance for severe gastroenteritis was implemented in public and private hospitals of Viña del Mar and Valparaiso (Region V) and of Chiguayante, Concepción, Penco, San Pedro de la Paz, Talcahuano and Tomé (Region VIII). All children <3 years of age residing in the districts, who consulted for severe gastroenteritis requiring oral or intravenous rehydration (equivalent to WHO plan B or C), or who were admitted to the hospital, were enrolled. Demographic and clinical information and a stool sample were obtained. Rotavirus was detected by ELISA and positive samples were serotyped by ELISA or real time PCR. Results: Between January 23 and June 30, 2003, a total of 760 children were recruited. Among these, 343 (45 percent) were admitted to the hospital. Stool samples were collected from 433 children. Among these, 214 were positive for rotavirus (49.4 percent). Overall, monthly disease incidence rates were 124/100,000 in V Region, and 114/100,000 in VIIIRegion. The predominant serotype was G4. Conclusions: Rotavirus was responsible for nearly half of the severe gastroenteritis episodes among children <3 years, during a predominantly G4 serotype season. Every year, approximately one every 70 children <3 years will have a severe rotavirus gastroenteritis episode.
Subject(s)
Child, Preschool , Female , Humans , Infant , Infant, Newborn , Male , Gastroenteritis/virology , Rotavirus , Rotavirus Infections/epidemiology , Age Distribution , Chile/epidemiology , Enzyme-Linked Immunosorbent Assay , Epidemiologic Methods , Gastroenteritis/epidemiology , Rotavirus/classification , Serotyping , Severity of Illness Index , Sex DistributionABSTRACT
Background:Cost effectiveness studies are essential to assess the real value of interventions with preventive or therapeutic objectives. Aim: To assess the theoretical cost-effectiveness of a vaccine against rotavirus in Chilean children of less than five years of age. Material and methods: An economic model was developed based on information on disease incidence, health care costs associated with treatment and the effectiveness and costs of vaccination. Net disease and vaccination costs were estimated from the health system perspective and were compared with life years and disability-adjusted life-years (DALYs) gained using a 3% discount rate. Local administrative and accounting hospital data and vaccine efficacy data were used to estimate healthcare costs and cost-effectiveness of vaccination. Results: A rotavirus vaccination program would prevent 10 deaths due to rotavirus gastroenteritis, 6,245 related hospitalizations and 41,962 outpatient visits during the first five years of life, per vaccinated cohort. For every 1,000 children born, the healthcare service spends US$15,077 on treatment of gastroenteritis. From the healthcare perspective, vaccination would yield a cost-effectiveness ratio of US$11,261 per DALY when the price of the vaccine is US$24 per course. Conclusions: Rotavirus vaccine can effectively reduce the disease burden and healthcare costs of rotavirus gastroenteritis and can be a cost-effective investment compared to other options.