Inpatient admission for febrile seizure and subsequent outcomes do not differ in children with vaccine-associated versus non-vaccine associated febrile seizures

Revaccination outcomes of children with vaccine proximate seizures

BACKGROUND

Seizures, whether febrile or afebrile, occurring within 14 days following vaccination can be considered as vaccine proximate seizures (VPSs). While the attributable risk and clinical severity of first febrile VPS is well known, the risk and clinical outcomes of VPS recurrence is less well defined.

METHODS

We conducted a retrospective review of revaccination management and outcomes in children who experienced a VPS as their first seizure seen in Australian Specialist Immunisation Clinics between 2013 and 2017. Vaccination outcomes were compared between children who had a VPS as their only seizure (VPS only) and children who had further non-vaccine proximate seizures following their initial VPS (VPS+) prior to review at the clinic.

RESULTS

We identified 119 children with a VPS as their first seizure, of which 61 (51%) went on to have other seizures (VPS+). Children with VPS+ were more likely to present at a younger age (6.2 vs 12.5 months, P = 0.03), with afebrile seizures (42.6% vs 15.5%, P = 0.002) compared to VPS only children. VPS recurrence on revaccination was uncommon in both groups, but more common in VPS+ children (12.5% vs 2.4%, P = 0.07). Having an epilepsy diagnosis, specifically Dravet syndrome, was associated with VPS recurrence (P < 0.001). Of the four children with Dravet syndrome who had VPS recurrence, all had status epilepticus following revaccination.

CONCLUSION

In children who presented with a single VPS as their only seizure, VPS recurrence on revaccination was uncommon. Children who had multiple non-vaccine proximate seizures following their initial VPS (VPS+) were more likely to present with afebrile VPS, at a younger age and have a VPS recurrence with vaccination. In these children, particularly those aged < 12 months, assessment and investigation for diagnosis of Dravet syndrome should be considered and additional precautions for revaccination undertaken as they are at highest risk of VPS recurrence.

Postvaccination Febrile Seizure Severity and Outcome

BACKGROUND

Febrile seizures (FSs) are a common pediatric condition caused by a sudden rise in temperature, affecting 3% to 5% of children aged ≤6 years. Although vaccination can cause FSs, little is known on whether FSs occurring in the time soon after vaccination (vaccine-proximate febrile seizures [VP-FSs] differ clinically from non-vaccine-proximate febrile seizures [NVP-FSs]). We compared the clinical profile and outcomes of VP-FS to NVP-FS.

METHODS

Prospective cohort study of children aged ≤6 years presenting with their first FS at 1 of 5 Australian pediatric hospitals between May 2013 and June 2014. Clinical features, management, and outcomes were compared between VP-FS and NVP-FS.

RESULTS

Of 1022 first FS cases (median age 19.8 months; interquartile range 13.6-27.6), 67 (6%) were VP-FSs. When comparing VP-FS to NVP-FS, there was no increased risk of prolonged (>1 day) hospitalization (odds ratio [OR] 1.61; 95% confidence interval [95% CI] 0.84-3.10), ICU admission (OR 0.72; 95% CI 0.10-5.48), seizure duration >15 minutes (OR 1.47; 95% CI 0.73-2.98), repeat FS within 24 hours (OR 0.80; 95% CI 0.34-1.89), or requirement for antiepileptic treatment on discharge (OR 1.81; 95% CI 0.41-8.02). VP-FS patients with a laboratory-confirmed infection (12%) were more likely to have a prolonged admission compared with those without.

CONCLUSIONS

VP-FS accounted for a small proportion of all FS hospital presentations. There was no difference in outcomes of VP-FS compared with NVP-FS. This is reassuring data for clinicians and parents of children who experience FS after vaccination and can help guide decisions on revaccination.

Febrile Seizures and Febrile Seizure Syndromes: An Updated Overview of Old and Current Knowledge

Febrile seizures are the most common paroxysmal episode during childhood, affecting up to one in 10 children. They are a major cause of emergency facility visits and a source of family distress and anxiety. Their etiology and pathophysiological pathways are being understood better over time; however, there is still more to learn. Genetic predisposition is thought to be a major contributor. Febrile seizures have been historically classified as benign; however, many emerging febrile seizure syndromes behave differently. The way in which human knowledge has evolved over the years in regard to febrile seizures has not been dealt with in depth in the current literature, up to our current knowledge. This review serves as a documentary of how scientists have explored febrile seizures, elaborating on the journey of knowledge as far as etiology, clinical features, approach, and treatment strategies are concerned. Although this review cannot cover all clinical aspects related to febrile seizures at the textbook level, we believe it can function as a quick summary of the past and current sources of knowledge for all varieties of febrile seizure types and syndromes.