Bordetella pertussis (Bp) disease: Before (2003-2011) and after (2013-2016) maternal immunization strategy in a...

Whooping cough continues to be a major cause of morbidity and mortality in infants younger than 1 year. In 2012, Argentina introduced Tdap in pregnancy to prevent infant mortality. The aim of this study is to describe the impact of maternal immunization on the hospitalization and mortality rates of confirmed Bordetella pertussis (Bp) cases by comparing pre- and post-Tdap vaccine recommendation periods.

All PCR-confirmed Bp cases from "R. Gutierrez" Children's Hospital identified between December 2003 and December 2016 were included in. Analysis was performed comparing hospitalization rates (per 10,000 discharges) between pre-vaccination (PreV) 2003-2011 and post-vaccination (PostV) 2013-2016 time periods, excluding the intervention year (2012).

During the study time frame, there were 1046 suspected Bp cases, of which 337 (32.2%) were confirmed. Three-hundred eight cases were analyzed (excluding year 2012): 237 in PreV and 71 in PostV. In comparison with PreV, PostV cases were older (3 vs 9 months; p < 0.001), and required less hospitalization (86.9% vs 67.6%; p < 0.001). Bp hospitalization rate (HR) decreased (22.3 vs 11.6; p < 0.001). The mortality rate in PreV 5.9% (14 cases); there were not deaths during PostV (p = 0.036).

Confirmed cases were among infants younger than 1 year In PostV, Bp cases were older and there was a significant decrease in the hospitalization rate. There were no fatal cases in our center after the pregnancy Tdap recommendation was implemented.