INTRODUCTION

Chickenpox is one of the most common vaccine-preventable diseases. In 1998, the World Health Organization recommended incorporating the vaccine into national vaccination programs. In Argentina, it was implemented in 2015. The objective of the study was to analyze the varicella time series in Tucuman during 2005-2019 and to evaluate the impact of the chickenpox vaccine on its incidence in Tucuman after its implementation.

METHODS

An ecological observational study was performed using secondary data sources. Chickenpox cases were those reported by the National Health Surveillance System. A description of the time series of reported chickenpox cases for Tucuman was made, and generalized additive models (GAM) were constructed using a negative binomial distribution. The impact of the vaccine was assessed by considering the period 2005-2014, a GAM model was constructed, and the most probable behavior was predicted for the following years (2015-2019). The impact was evaluated by comparing predicted and observed rates with their confidence intervals.

RESULTS

Tucuman reported 82,810 cases during 2005-2019. The annual rate varied between 1.66 per 1000 inhabitants (2019) and 6.04 per 1000 inhabitants (2007). The series showed seasonality and in recent years a decreasing trend. A significant decrease in the incidence rate was observed after vaccine implementation.

DISCUSSION

This work showed the impact of implementing public policies such as vaccines.

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