Estimation of influenza and respiratory syncytial virus hospitalizations using sentinel surveillance data-La Paz, Bolivia. 2012-2017.

OBJECTIVE: The objective was to estimate the number of hospitalizations associated with influenza and RSV using data from severe acute respiratory infection (SARI) sentinel surveillance from El Alto-La Paz. Bolivia. METHODS: All persons who met the case definition for SARI at one sentinel hospital had a clinical sample collected and analyzed by rRT-PCR for influenza and by indirect immunofluorescence for RSV. The SARI-influenza and SARI-RSV case counts were stratified by six age groups. The proportion of cases captured in the sentinel hospital in relation to the non-sentinel hospitals of area was multiplied by the age-specific census population, to build the denominators. The annual incidence and a 95% confidence interval (CI) were estimated. RESULTS: During 2012-2017, n = 2606 SARI cases were reported (average incidence 120/100 000 inhabitants [95% CI: 116-124]); the average incidence of influenza-associated SARI hospitalization was 15.3/100 000 (95% CI: 14.1-16.7), and the average incidence of RSV-associated SARI hospitalization was 9/100 000 inhabitants (95% CI: 8.1-10.1). The highest incidence of influenza was among those less than one year of age (average 174.7/100 000 [range: 89.1-299.5]), followed by those one to four years of age (average 51.8/100 000 [range: 19.8-115.4]) and then those 65 years of age and older (average 47.7/100 000 [range: 18.8-117]). For RSV, the highest incidence was highest among those less than one year of age (231/100 000 [range: 119.9-322.9]). CONCLUSION: Influenza and RSV represent major causes of hospitalization in La Paz, Bolivia-with the highest burden among children under one year of age. Our estimates support current prevention strategies in this age group.