Exploring the risk factors for vaccine-associated and non-vaccine associated febrile seizures in a large pediatric cohort

Effects of coronavirus disease 2019 vaccination on seizures in patients with epilepsy

BACKGROUND

Given that seizures may be triggered by vaccination, this study aimed to evaluate the risk and correlative factors of seizures in patients with epilepsy (PWE) after being vaccinated against coronavirus disease 2019 (COVID-19).

METHODS

This study retrospectively enrolled PWE who were vaccinated against COVID-19 in the epilepsy centers of 11 hospitals in China. We divided the PWE into two groups as follows: (1) patients who developed seizures within 14 days of vaccination were assigned to the SAV (with seizures after vaccination) group; (2) patients who were seizure-free within 14 days of vaccination were assigned to the SFAV (seizure-free after vaccination) group. To identify potential risk factors for seizure reccurence, the binary logistic regression analysis was performed. Besides, 67 PWE who had not been vaccinated were also included for elucidating the effects of vaccination on seizures recurrence, and binary logistic regression analysis was performed to determine whether vaccination would affect the recurrence rate of PWE who had drug reduction or withdrawal.

RESULTS

The study included a total of 407 patients; of which, 48 (11.8%) developed seizures within 14 days after vaccination (SAV group), whereas 359 (88.2%) remained seizure-free (SFAV group). The binary logistic regression analysis revealed that duration of seizure freedom ( P  < 0.001) and withdrawal from anti-seizure medications (ASMs) or reduction in their dosage during the peri-vaccination period were significantly associated with the recurrence of seizures (odds ratio = 7.384, 95% confidence interval = 1.732-31.488, P  = 0.007). In addition, 32 of 33 patients (97.0%) who were seizure-free for more than three months before vaccination and had a normal electroencephalogram before vaccination did not have any seizures within 14 days of vaccination. A total of 92 (22.6%) patients experienced non-epileptic adverse reactions after vaccination. Binary logistic regression analysis results showed that vaccine did not significantly affect the recurrence rate of PWE who had the behavior of ASMs dose reduction or withdrawal ( P  = 0.143).

CONCLUSIONS

PWE need protection from the COVID-19 vaccine. PWE who are seizure-free for >3 months before vaccination should be vaccinated. Whether the remaining PWE should be vaccinated depends on the local prevalence of COVID-19. Finally, PWE should avoid discontinuing ASMs or reducing their dosage during the peri-vaccination period.

Effect of inactivated COVID-19 vaccines on seizure frequency in patients with epilepsy: A multicenter, prospective study

Objectives

Several COVID-19 vaccines list "uncontrolled epilepsy" as a contraindication for vaccination. This consequently restricts vaccination against COVID-19 in patients with epilepsy (PWE). However, there is no strong evidence that COVID-19 vaccination can exacerbate conditions in PWE. This study aims to determine the impact of COVID-19 vaccination on PWE.

Methods

PWE were prospectively recruited from 25 epilepsy centers. We recorded the seizure frequency at three time periods (one month before the first vaccination and one month after the first and second vaccinations). A generalized linear mixed-effects model (GLMM) was used for analysis, and the adjusted incidence rate ratio (AIRR) with 95% CI was presented and interpreted accordingly.

Results

Overall, 859 PWE were included in the analysis. Thirty-one (3.6%) and 35 (4.1%) patients were found to have increased seizure frequency after the two doses, respectively. Age had an interaction with time. The seizure frequency in adults decreased by 81% after the first dose (AIRR=0.19, 95% CI:0.11-0.34) and 85% after the second dose (AIRR=0.16, 95% CI:0.08-0.30). In juveniles (<18), it was 25% (AIRR=0.75, 95% CI:0.42-1.34) and 51% (AIRR=0.49, 95% CI:0.25-0.95), respectively. Interval between the last seizure before vaccination and the first dose of vaccination (ILSFV) had a significant effect on seizure frequency after vaccination. Seizure frequency in PWE with hereditary epilepsy after vaccination was significantly higher than that in PWE with unknown etiology (AIRR=1.95, 95% CI: 1.17-3.24). Two hundred and seventeen (25.3%) patients experienced non-epileptic but not serious adverse reactions.

Discussion

The inactivated COVID-19 vaccine does not significantly increase seizure frequency in PWE. The limitations of vaccination in PWE should focus on aspects other than control status. Juvenile PWE should be of greater concern after vaccination because they have lower safety. Finally, PWE should not reduce the dosage of anti-seizure medication during the peri-vaccination period.

Vaccinomics: a cross-sectional survey of public values

Objective: We characterize public values regarding vaccinomics, which aims to improve vaccine safety and effectiveness using genomics.Methods: Panel survey (2020) of ≥18-year-olds with embedded animation introduced vaccinomics. Sociodemographic, health, and vaccination-related items were adapted from validated scales. Novel items measured trust in public health authorities, vaccinomics-related values, and preferences for federal funding: vaccinomics compared with vaccine issues and chronic diseases. Beginning and end of survey confidence in vaccine safety was measured to assess potential changes. Data were weighted to the U.S. Census. Vaccinomics-related concerns were stratified by sociodemographic characteristics, vaccine hesitancy status (composite outcome), reported serious vaccine reactions, and trust in public health authorities (PHA). Log binomial regression models estimated associations between these variables and agency to make vaccine-related decisions.Results: Most (70.7%, N = 1,925) respondents expected vaccinomics would increase their vaccine confidence compared to now. Agreement was highest among those without serious vaccine reaction experience (unexperienced: 74.2% versus experienced: 62.3%), with high trust in PHA (high: 83.3% versus low: 57.4%), and low vaccine hesitancy among parents of teenagers (low: 78.8% versus high: 62.5%) and adults without minor children (low: 79.8% versus high: 60.6%; all p < .01). Belief that vaccination was an individual's choice was associated with reported serious reactions (adjusted Prevalence Ratio (aPR): 1.16; 95% CI: 1.07, 1.25) and low trust (aPR: 0.91; 0.84, 0.98). Beginning versus end of survey vaccine safety perceptions were similar.Conclusion: Federal funding, communications, and policies should assure the public that vaccinomics will not remove their decision-making power and engender trust in PHA.

Vaccination in acute immune-mediated/inflammatory disorders of the central nervous system

This review article covers the vaccination related issues in autoimmune disorders of central nervous system (CNS) including narcolepsy, anti-NMDAR encephalitis, Rasmussen encephalitis and febrile infection related epilepsy syndrome (FIRES). Beyond these conditions the immune mediated epilepsies related with autoimmune CNS disorders are discussed and indications and contraindications of vaccinations in these cases are also considered.

Ethical and policy implications of vaccinomics in the United States: community members' perspectives

Objectives: We aimed to elucidate public values regarding the use of genomics to improve vaccine development and use (vaccinomics).

Methods: Adults ≥18 years-old were recruited through social media and community organizations, and randomly assigned to one of four nested discussion groups in Boulder, CO and Baltimore, MD. Participants rated their confidence in vaccine safety and effectiveness prior to and after discussing vaccinomics. Before departing, they prioritized funding for vaccinomics versus federal priorities (vaccine safety and efficacy, new vaccines, and free vaccines) and chronic diseases (cancer, heart disease, and diabetes). Grounded Theory-influenced methods were used to identify themes.

Results: Participants broadly supported vaccinomics. Emergent themes: concerns about reduced privacy/confidentiality, increased genetically based stigma/discrimination, and reduced agency to make vaccine-related decisions through genetically based prioritization. Participants supported vaccinomics’ potential for increased personalization. Some participants favored prioritizing others over themselves during a vaccine shortage, while others did not. Some participants worried health insurance companies would discriminate against them based on information discovered through vaccinomics. Participants feared inequitable implementation of vaccinomics would contribute to discrimination and marginalization of vulnerable populations. Discussing vaccinomics did not impact perceptions of vaccine safety and effectiveness. Federal funding for vaccinomics was broadly supported.

Conclusion: Participants supported vaccinomics’ potential for increased personalization, noting policy safeguards to facilitate equitable implementation and protect privacy were needed. Despite some concerns, participants hoped vaccinomics would improve vaccine safety and effectiveness. Policies regarding vaccinomics’ implementation must address public concerns about the privacy and confidentiality of genetic information and potential inequities in access to vaccinomics’ benefits.

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.

Parental risk factors for fever in their children 7-10 days after the first dose of measles-containing vaccines

We evaluated whether parental clinical conditions were associated with fever after a first dose of measles-containing vaccine (MCV) in the child in a cohort study including 244,125 children born in Kaiser Permanente Northern California between 2009 and 2016 who received MCV between ages 1 and 2 years. Each child was linked with his/her mother and father when possible. Parental clinical conditions present before and after their child’s birth were identified. We defined fever in the children as clinic and emergency department visits with a fever code 7–10 days after a first dose of MCV (“MCV-associated fever”). We evaluated parental clinical conditions associated with MCV-associated fever using multivariate logistic regression analyses. After adjusting for multiple factors, including healthcare utilization, maternal fever [odds ratio (OR) = 1.19, 95% confidence interval (CI) 1.06–1.32], fever after MCV (OR = 5.90, 95% CI 1.35–25.78), respiratory infections (OR = 1.20, 95% CI 1.10–1.31), migraine (OR = 1.14, 95% CI 1.05–1.24), syncope (OR 1.14, 95% CI 1.01–1.27), and essential thrombocythemia (OR = 1.93, 95% CI 1.15–3.25) were significantly associated with MCV-associated fever. Paternal respiratory infections (OR = 1.15, 95% CI 1.05–1.27), fever associated with respiratory infections (OR = 1.47, 95% CI 1.23–1.76), and vitiligo (OR = 1.63, 95% CI 1.06–2.53) were significantly associated with MCV-associated fever. Parental clinical conditions, specifically fever alone and fever associated with respiratory infection, are associated with fever in their child 7–10 days after MCV.

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.

Similar relative risks of seizures following measles containing vaccination in children born preterm compared to full-term without previous seizures or seizure-related disorders

BACKGROUND

Febrile seizures are associated with the first dose of measles-containing vaccines and the risk increases with chronologic age during the second year of life. We used the Vaccine Safety Datalink (VSD) to determine if the relative increase in risk of seizures following receipt of measles-containing vaccine differs by gestational age at birth.

METHODS

Children were eligible if they received their first dose of measles-containing vaccine at age 12 through 23 months from January 2003 through September 2015. Children were excluded if they had a history of seizure or conditions strongly related to seizure prior to 12 months of age. Seizures were identified by diagnostic codes in the inpatient or emergency department settings. Using risk-interval analysis, we estimated the incidence rate ratio (IRR) for seizures in the 7 through 10 days (risk period) vs 15 through 42 days (control period) following receipt of measles-containing vaccines in children born preterm (<37 weeks gestation age) and those born full-term (≥37 weeks).

RESULTS

There were 532,375 children (45,343 preterm and 487,032 full-term) who received their first dose of measles-containing vaccine at age 12 through 23 months. The IRRs of febrile seizures 7 through 10 days compared with 15 through 42 days after receipt of measles-containing vaccine were 3.9 (95% CI: 2.5-6.0) in preterm children and 3.2 (2.7-3.7) in full-term children; the ratio of IRRs: was 1.2 (0.76-1.9), p = 0.41. IRRs were also similar across gestational age groups, by vaccine type received (measles-mumps-rubella [MMR] or measles-mumps-rubella-varicella [MMRV]) and age at vaccination (12-15 or 16-23 months).

CONCLUSION

Vaccination with a measles-containing vaccine in the second year of life is associated with a similar relative risk of a first seizure in children born preterm as in those who were born full-term.

Risk factors and familial clustering for fever 7-10days after the first dose of measles vaccines

BACKGROUND

Seven to ten days after a first dose of a measles-containing vaccine (MCV; i.e., MMR or MMRV), children have elevated fever risk which can be associated with febrile seizures. This study investigated individual and familial factors associated with fever 7-10days after MCV.

METHODS

Retrospective cohort study among children who were <36months of age at receipt of MCV in six sites of the Vaccine Safety Datalink from 1/1/2000 to 12/31/2012. We evaluated medically-attended clinic or emergency department visits with a code for fever 7-10days after any MCV ("MCV- associated"). We evaluated factors associated with MCV-associated fever using χ² and multivariable logistic regression analyses.

RESULTS

Among 946,806 children vaccinated with MCV, we identified 7480 (0.8%) MCV-associated fever visits. Compared with children without fever after MCV, children with MCV-associated fever were more likely to have received MMRV than MMR (OR 1.3 95% CI 1.2, 1.5), have had medically attended fever both following previous vaccines (OR 1.3 95% CI 1.1, 1.6) and at any other previous time (OR 1.7 95% CI 1.6, 1.8), have had at least 1 prior seizure (OR 2.2 95% CI 1.7, 2.7), and have had >3 medical visits within the 6months before MCV (OR 1.7 95% CI 1.6, 1.8). In families with multiple MCV-immunized children, after adjusting for healthcare seeking behavior care for fever, those whose siblings had MCV-associated fever were more likely to also have MCV-associated fever (OR 3.5 95% CI 2.5, 4.8).

DISCUSSION

Children who received MMRV vaccine or who had prior medically-attended fevers and seizures during the first year of life had increased risk of fever after a first dose of measles vaccine. After adjusting for familial propensity to seek care, MCV-associated fever still clustered within families, suggesting a possible genetic basis for susceptibility to developing fever due to measles vaccines.

The weight of MMRV-related febrile convulsions among other clinical factors contributing to febrile convulsions in children

BACKGROUND

It was previously demonstrated that MMRV vaccine causes a higher rate of febrile convulsions (FC) compared to the MMR vaccine. Additional risk factors for FC include age, familial tendency, day care attendance, viral diseases, complications at birth and developmental delay.

OBJECTIVE

We evaluated the relative and attributable risk of FC for vaccinees' age, ethnicity, low birth weight, preterm birth and MMRV vaccination in 10-24 months old children.

METHODS

Data on medical history and vaccination were extracted from data warehouses of Clalit Health Services and Israel's Ministry of Health and linked on an individual record level for 90,294 MMR- and 8344 MMRV-vaccinees. A retrospective study design was used to reveal the risk factors associated with FC in study participants.

RESULTS

During the second week after immunization, an elevated relative risk of FC was demonstrated in MMRV-recipients (adjusted RR=2.16 (95%CI: 1.01; 4.64)). However, the cumulative incidence of FC during the entire 40-day observation period did not differ between the MMR and MMRV vaccinees. The MMRV-specific attributable risk of FC was not statistically significant at any point of observation period and was exceedingly low compared to other risk factors, equaling 5.3 FC cases per 10,000 vaccinees (95%CI: -1.4; 12.2).

DISCUSSION

Our findings demonstrate that MMRV-associated FC in 10-24 months old contributes very marginally to the overall rate of FC in this population.

CONCLUSION

Given the low number of MMRV-specific FC cases, their transient nature and the benefit of vaccination, the overall benefit-risk of the vaccine can be considered favourable. Nonetheless, the option of separate immunization with MMR+V should be offered to parents, in order to maintain sufficient vaccine uptake in the population.