Guillermo G Barrenechea1, Leonardo S Bastos2. 1. Departamento Bioquímico-Laboratorio de Salud Pública, Mendoza 128 4° Piso, San Miguel de Tucumán, Tucumán CP: 4107, Argentina; Dirección de Investigación en Salud, Virgen de la Merced 189 1° Piso, San Miguel de Tucumán, Tucumán CP: 4107, Argentina. Electronic address: barrenecheagg@gmail.com. 2. Scientific Computing Program, Oswaldo Cruz Foundation, Av. Brasil, 4365, Manguinhos, Rio de Janeiro CEP: 21040-900, Brazil; Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK.
Abstract
INTRODUCTION: Varicella, also known as chickenpox is one of the most common immunizable diseases. In 1998, the World Health Organization (WHO) recommended to incorporate this vaccine in the national immunization programs, which Argentina did in 2015. OBJECTIVES: To describe the behavior of the varicella time series for the 2005-2017 period, and to evaluate the impact of the vaccine in Argentina. METHODOLOGY: An ecological observational study was performed, using the varicella cases reported in the National Health Monitoring System, and the data of the National census as secondary data sources. A model based time series analysis of the notified varicella cases in Argentina was performed, using a Negative Binomial Mixed Model. For the verification of the vaccine impact, the 2005-2014 period was selected, and a prognosis for the following years was performed. Impact was evaluated by comparing the rates and confidence intervals between the predicted and observed values. RESULTS: Argentina reported 1,775,587 varicella cases for the 2005-2017 period. The series exhibited seasonality, and, a decreasing trend in the number of cases was observed in 2016 and 2017. A reduction of the incidence rate after the implementation of the vaccine was observed. The transmission risk decreased in the country after vaccine implementation. CONCLUSIONS: This study is the first concrete evidence of the varicella incidence decline after the implementation of a single dose application program in Argentina.
INTRODUCTION: Varicella, also known as chickenpox is one of the most common immunizable diseases. In 1998, the World Health Organization (WHO) recommended to incorporate this vaccine in the national immunization programs, which Argentina did in 2015. OBJECTIVES: To describe the behavior of the varicella time series for the 2005-2017 period, and to evaluate the impact of the vaccine in Argentina. METHODOLOGY: An ecological observational study was performed, using the varicella cases reported in the National Health Monitoring System, and the data of the National census as secondary data sources. A model based time series analysis of the notified varicella cases in Argentina was performed, using a Negative Binomial Mixed Model. For the verification of the vaccine impact, the 2005-2014 period was selected, and a prognosis for the following years was performed. Impact was evaluated by comparing the rates and confidence intervals between the predicted and observed values. RESULTS: Argentina reported 1,775,587 varicella cases for the 2005-2017 period. The series exhibited seasonality, and, a decreasing trend in the number of cases was observed in 2016 and 2017. A reduction of the incidence rate after the implementation of the vaccine was observed. The transmission risk decreased in the country after vaccine implementation. CONCLUSIONS: This study is the first concrete evidence of the varicella incidence decline after the implementation of a single dose application program in Argentina.
Authors: Norberto Giglio; Pieralessandro Lasalvia; Manjiri Pawaskar; Cintia I Parellada; Yaneth Gil Rojas; Paula Micone; Virginia V Babic; Silvina E Neyro Journal: Vaccines (Basel) Date: 2022-07-20