A hypotonic-hyporesponsive episode (HHE) is defined as sudden onset of poor muscle tone, reduced consciousness, and pale or bluish skin occurring within 48 hours after vaccination, most commonly pertussis vaccination.[2] An HHE is estimated to occur after 1 in 4,762 to 1 in 1,408 doses of whole cell pertussis vaccine, and after 1 in 14,286 to 1 in 2,778 doses of acellular pertussis vaccine.[3]
| Hypotonic-hyporesponsive episode (HHE) | |
|---|---|
| Symptoms | Hypotonia, hyporesponsiveness, pallor, cyanosis.[1][2] |
| Usual onset | 1 minute to 48 hours post-vaccination.[1] |
| Duration | 1 minute to 14 days (median 10 hours).[1] |
| Causes | Vaccination, most commonly pertussis vaccine.[1] |
| Diagnostic method | Based on symptoms.[1][3] |
| Differential diagnosis | Vasovagal syncope, seizure |
| Prevention | Those who experience an HHE after pertussis vaccination may avoid further pertussis vaccines.[1][4] |
| Treatment | Usually resolves on its own, management involves checking the airway, breathing, and circulation, and hospitalization for observation and to rule out other conditions.[5][1][6] |
| Deaths | None reported |
References edit
- ^ a b c d e f g "Hypotonic, hyporesponsive episode (HHE)" (PDF). 7 January 2006. Retrieved 2018-01-24.
- ^ a b Duvernoy, Tracy S.; Braun, M. Miles (October 2000). "Hypotonic–Hyporesponsive Episodes Reported to the Vaccine Adverse Event Reporting System (VAERS), 1996–1998 | ELECTRONIC ARTICLE". Pediatrics. 106 (4): e52. doi:10.1542/peds.106.4.e52. PMID 11015547. S2CID 12743062. Retrieved 2018-01-22.
- ^ a b Bonhoeffer, Jan. "Hypotonic-hyporesponsive episode (HHE) as an adverse event following immunization in early childhood: Case definition and guidelines for data collection, analysis, and presentation | Jan Bonhoeffer". Vaccine. Retrieved 2018-02-01.
- ^ "Pinkbook | Pertussis | Epidemiology of Vaccine Preventable Diseases". CDC. Retrieved 2018-01-24.
- ^ "Hypotonic-Hyporesponsive Episodes to Immunisation".
- ^ Duvernoy, Tracy S.; Braun, M. Miles (October 2000). "Hypotonic–Hyporesponsive Episodes Reported to the Vaccine Adverse Event Reporting System (VAERS), 1996–1998 | ELECTRONIC ARTICLE". Pediatrics. 106 (4): e52. doi:10.1542/peds.106.4.e52. PMID 11015547. S2CID 12743062. Retrieved 2018-01-24.
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