Characterization of hypotonia-hyporesponsiveness after pentavalent vaccine and neurodevelopmental screening in children under 6 years of age, 2013 - 2018, Uruguay

Abstract

Background: Hypotonic-hyporesponsive episodes (HHE) is one frequently reported neurologic adverse effect supposedly attributable to vaccination and immunization.  Its long-term impact on neurodevelopment is not completely known. Aim: To characterize the post-pentavalent vaccine HHE events reported to the Uruguayan Ministry of Health (M of H) between 2014 and 2018. To perform neurodevelopment screening of those who were under 6 years of age at the time of evaluation. Methods: Descriptive study of the reports made to the National Farmacosurveillance System of the M of H. Neurodevelopment screening was performed using the National Guidelines for Developmental Surveillance. Results: 30 cases were studied. Most cases occurred after the first doses, were of short duration and during the first hours after vaccination, with spontaneous recovery. Median time between the event and this evaluation was 2 years and 2 months. Screening tests were normal in 15. Delay in the language area was detected in one case. Conclusions: HHE events had similar characteristics to those described in the literature, with no severe short-term complications. Despite the limitations of the present study, no delays nor deviations were found in the development of the children who were evaluated.