Identifying signatures of the impact of rotavirus vaccines on hospitalizations using sentinel surveillance data from Latin American countries.

BACKGROUND: Passive surveillance data are often the only available source of data that can be used to evaluate the population-level impact of vaccination, but such data often suffer from important limitations such as changes in surveillance efforts. This study provides an example of how to identify important signatures of rotavirus vaccine impact, including evaluating the overall effectiveness and changes in rotavirus seasonal dynamics. METHODS: We used data from a standardized sentinel rotavirus surveillance network in six Latin American countries (Bolivia, El Salvador, Guatemala, Honduras, Paraguay, and Venezuela) from 2004 to 2017. A random-effects model was used to evaluate changes in the proportion of rotavirus-associated hospitalizations following vaccine introduction. Harmonic regression models were used to estimate vaccine impact on the number of rotavirus hospitalizations, controlling for trends in rotavirus-negative cases. Changes to rotavirus seasonality were evaluated using center of gravity analysis, wavelet analysis, and harmonic regression. RESULTS: All countries observed declines in the proportion of rotavirus-positive acute diarrhea samples with a mean reduction of 16% (95% confidence interval: 10-22%). We estimate that each 10% increase in vaccine coverage was associated with declines in the number of rotavirus-positive cases, ranging from 4.3% (1.3-7.2%) in Honduras to 21.4% (16.8-25.9%) in Venezuela. The strength of the seasonal peak in rotavirus incidence became smaller after vaccine introduction in Guatemala, Honduras, and Venezuela. Seasonal peaks also shifted later in the surveillance year, especially in higher-mortality countries. CONCLUSIONS: The combination of methods we applied have different strengths that allow us to identify common signatures of rotavirus vaccine impact.

Carga de influenza en la comunidad de Barrio Obrero. Paraguay / Burden of Influenza in the community of Barrio Obrero. Paraguay

La influenza (FLU) causa morbilidad grave y mortalidad. El objetivo del estudio fue evaluar la incidencia, la etiología y el uso de recursos para la gripe en un barrio de bajos ingresos de Asunción, Paraguay mediante un estudio de cohorte prospectiva de base poblacional con muestreo aleatorio estratificado de viviendas de julio a Octubre de 2013. El monitoreo de los hogares para la identificación de los casos de enfermedad tipo influenza (ETI) fue telefónico. En aquellos pacientes con ETI, se tomaron hisopados nasofaríngeos para RT-PCR e IFI. Se establecieron los factores de riesgo para ETI por la prueba de chi cuadrado considerándose significativa p<0,05; además se calculó RR con IC95%. De 8.279 viviendas, 401 familias (2.065 personas) fueron monitoreadas; se identificaron 141 casos de ETI que representa una incidencia de 6,8% (IC95%: 5,5-7,6%); el 56% de los casos buscaron atención médica, en su mayoría (80%) en servicios públicos. Se testaron 84% de los hisopados nasofaríngeos, siendo positivo en el 22% para virus respiratorios; 86% FLU (63% FLU A, 37% FLU B). Se encontró asociación (p< 0,001) entre enfermar de ETI y tener edad menor de 5 años (RR: 2,43 (1,68-3,49). Este es el primer estudio que da información sobre la carga de Influenza en Paraguay. El monitoreo telefónico resultó ser una buena estrategia para monitoreo de los hogares para la identificación de los casos de ETI. El virus de la Influenza fue el patógeno más común identificado, con una alta demanda de asistencia médica, lo que resulta una carga sustancial para los servicios de salud.

Influenza (FLU) causes severe morbidity and mortality. This study aimed to evaluate the incidence, etiology and use of resources for influenza in a low-income neighborhood in Asunción, Paraguay through a prospective population base cohort with stratified random sampling of houses from July to October 2013. Monitoring of cases of influenza-like illness (ILI) was by telephone. In ETI cases, nasopharyngeal swabs were collected for RT-PCR and IFI. Risk factors for ETI were established using chi square test at p≤0.05; RR with CI 95% was also calculated. Of 8,279 homes, 401 families (2,065 people) were monitored; 141 ILI cases were identified, yielding an incidence of 6.8% (95% CI 5.5-7.6), 56% of cases sought medical attention, mostly (80%) in public health services. Among the ILIs, 84% of nasopharyngeal swabs were tested, 22% positive for respiratory viruses; 86% FLU (63% FLU A, 37% FLU B). An association (p<0.001) between ILI disease and aged less than 5 years (RR: 2.43 (1.68-3.49) was found. This is the first study that gives information on Influenza burden in Paraguay. Telephone monitoring was a good strategy for house monitoring in order to identify cases of ILI. Influenza virus was the most common pathogen identified, with a high demand for medical assistance, which results in a substantial burden for health services.