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.

Astrovirus detection in sporadic cases of diarrhea among hospitalized and non-hospitalized children in Rio De Janeiro, Brazil, from 1998 to 2004.

We analyzed 379 stool samples collected from January 1998 through December 2004, from hospitalized and non-hospitalized children with diarrhea in Rio de Janeiro, Brazil. These samples had prior negative results for other enteric viruses and bacterial pathogens. The specimens were analyzed for HAstV detection by RT-PCR. HAstV genotypes were determined by sequence analysis of the RT-PCR products. Twenty (5.3%) out of 379 samples were positive for astrovirus. Astrovirus was equally common among inpatients and outpatients and among different age groups. Of 20 HAstV-infected children, 13 (65%) were either hospitalized or received medical care in the emergence department, which suggests that they had a more severe illness. Only 7 (35%) of the 20 HAstV-infected children attended walk-in clinics, which suggests that they had mild disease. Other then diarrhea, fever was the most common symptom among the HAstV-positive patients, followed by vomit and bloody diarrhea. HAstV-1 was the predominant strain although genotypes 2 and 4 were also found. There was no obvious difference among HAstV strains detected from inpatients or outpatients or among different age groups. The study documented that astrovirus is an agent of acute diarrhea in children who are inpatients or outpatients in Rio de Janeiro, Brazil although it seems to be less common as a single cause of childhood diarrhea then rotavirus.

Human bocavirus infection in children with gastroenteritis, Brazil.

Human bocavirus (HBoV) was detected in 14 (2%) of 705 fecal specimens from Brazilian children with gastroenteritis. Coinfection with rotavirus, adenovirus, or norovirus was found in 3 (21.4%) HBoV-positive specimens. None of the HBoV-positive patients had respiratory symptoms.

Norovirus detection and genotyping for children with gastroenteritis, Brazil.

During 1998-2005, we analyzed stool samples from 289 children in Rio de Janeiro to detect and genotype no-rovirus strains. Previous tests showed all samples to be negative for rotavirus and adenovirus. Of 42 (14.5%) no-rovirus-positive specimens, 20 (47.6%) were identified as genogroup GI and 22 (52.3%) as GII.