Hypotonic-hyporesponsive episodes after administration of hexavalent DTP-based combination vaccine: A description of 12 cases

Abstract

Hypotonic-hyporesponsive (HHE) episodes are known and recognized phenomena, which typically occur within 48 hours of immunisation..Our aim is to describe 12 cases of HHE brought to the Center of Pediatric Sleep Medicine, with attention to the clinical features of the episode and their follow-up. Medical charts of infants visited between 2005-2015 were reviewed. Twelve infants showed a HHE using HHE using Brighton Collaboration Criteria. All infants received a Hexavalent diphtheria -tetanus -pertussis acellular component -hepatitis B-,inactivated poliovirus-Haemophilus influenzae type-b conjugate vaccine. Five out of 12 were brought to Emergency Department, where 2 were symptomatic (one was hyporeactive, the other had fever). No infant died during the episode, or the follow-up, nor developed neurological disease after subsequent vaccinations. HHE are confirmed as benign events, even after administration of hexavalent vaccination, devoid of negative neuropsychomotor outcome.

Post-marketing surveillance of adverse events following measles, mumps, rubella and varicella (MMRV) vaccine: retrospecive study in apulia region (ITALY), 2009-2017

“…Applying the Causality Assessment algorithm, the cause/effect relationship between vaccination and adverse events is inconsistent, because hypotonic-hyporesponsive episodes are very rare AEFIs that can occur within 48 h after the vaccine administration. 39 …”

Postmarketing surveillance of adverse events following meningococcal B vaccination: data from Apulia Region, 2014–19

“…In 7/31 serious AEFI classified as consistent with immunization a hypotonic-hyporesponsive episode was notified: our findings are in line with the previously published literature regarding the benignity of the episodes, as they mostly resolved briefly and all the infants returned to the prevaccination status with no alteration in neuropsychomotor development. 46 An emerging issue must be studied in future research: the experience of an AEFI as determinants of missing vaccination schedule. In our report, we documented that 19/28 people with an history of serious AEFIs missed the competition of vaccination cycle and this phenomenon could be very important for Public Health.…”

“…In 7/31 serious AEFI classified as consistent with immunization a hypotonic-hyporesponsive episode was notified: our findings are in line with the previously published literature regarding the benignity of the episodes, as they mostly resolved briefly and all the infants returned to the prevaccination status with no alteration in neuropsychomotor development. 46 …”

Economic assessment of incorporating the Hexavalent vaccine as part of the National Immunization Program of Peru

“…All vaccines assessed are administered within the rst year of life;(2) therefore, the time horizon for the present analysis was 1 year. This will capture the majority of local and systemic adverse reactions, which usually appear within hours to days of vaccine administration (2,(26)(27)(28).…”