Once vaccines became available in 2021, many people with epilepsy were unsure whether to get vaccinated. Some had concerns similar to those in the general population, but people with epilepsy also were concerned about seizure risk and effects on anti-seizure medications.
Does COVID-19 infection increase new-onset seizures or epilepsy incidence in the population?
There is no evidence that it does.
It’s complicated, if not impossible, to show whether COVID-19 infections are associated with an increase in epilepsy incidence or prevalence, said Bernhard Steinhoff, who spoke at the European Epilepsy Congress in Geneva in July 2022. “From a methodological point of view, we can’t really answer this,” he said. “There are so many potential variables.”
Studies also would need to differentiate acute symptomatic seizures from new-onset epilepsy, he noted. And without more research on biological mechanisms, it’s not possible to say whether COVID-19 infections are leading to cases of epilepsy that wouldn’t have existed otherwise.
Was the COVID-19 pandemic associated with increases in seizure frequency?
Yes – but they were not due to infections or vaccinations.
The research literature does show that some people experienced increases in seizure frequency during the pandemic, but the increases were related to health system and social issues, including interruptions in medication availability, decreased access to care, and increased stress.
A recent systemic review found that 18.5% of people with epilepsy experienced increases in seizure frequency during the pandemic. And a study from Uganda found that during lockdown, 23.5% of surveyed people with epilepsy said their seizure frequency had increased. In this study, 49% believed that people with epilepsy were more likely to be infected with COVID-19 than other people, misinformation that may have caused them to avoid seeking follow-up care during the pandemic.
Whether COVID-19 infection itself increases seizure frequency in people with epilepsy is mostly unknown, though many studies have attempted to address the question. “We have wonderful papers and large groups of patients, but there is such a mix of patients [and epilepsy types],” Steinhoff said. “Or you have studies that use patients from a selective, homogenous group, but those are small studies.”
Steinhoff and colleagues conducted a recent study using a year’s worth of data from outpatients at Kork Epilepsy Center in Germany. They identified 51 people with epilepsy who had PCR-confirmed COVID-19 infection. Of those, 7.8% experienced increases in seizure frequency.
Are people with epilepsy at increased risk for more serious cases of COVID-19 infection?
If they are, it is likely due to comorbidities or other factors – not epilepsy itself.
“I would guess that the course of COVID-19 infection and mortality rate might be different in people with epilepsy from the general population,” said Steinhoff. “It’s almost impossible to see in the data, but I believe some people with epilepsy do have higher risks with infection, but that is due to their comorbidities rather than to the epilepsy.”
J. Helen Cross, ILAE president, agreed. “There are many people in which a comorbidity is a risk factor” for severe infection or mortality, she said. “This could be cancer, immune suppression, hypertension, obesity. People with epilepsy cover the whole age range and they often have other comorbidities, so to tease out whether epilepsy per se is a risk factor is very difficult.”
A recent systematic review and meta-analysis evaluated outcomes in people with epilepsy compared to people without epilepsy. Epilepsy was associated with a higher risk of severe COVID-19 outcomes (OR 1.69; 95% CI 1.11-2.59) and a higher mortality risk (OR 1.71; 95% CI: 1.14-2.56). However, the data were inadequate to assess the impact of comorbidities. The impacts of epilepsy type, seizure type, treatment type, and extent of seizure control also could not be determined. The authors noted that most of the studies in the review had major limitations.
Preventing COVID-19 infection in people with epilepsy may reduce the risk of mortality. A recent study in the UK that used medical records from nearly 7 million people found that after vaccination, epilepsy was not a risk factor for increased mortality due to COVID-19-infection.
Vaccine effectiveness: The COVID Symptom Study
Research that has surveyed people with epilepsy has found several concerns regarding vaccination. Most are epilepsy related, but a certain percentage of people with epilepsy—as with people in the general population—have concerns about vaccine effectiveness.
The COVID Symptom Study (UK) used data on about 1 million people who were vaccinated with at least one dose. People reported their COVID-19 vaccinations, as well as any subsequent COVID-19 infection, through a mobile app. The study used several control groups. It did not focus on people with epilepsy, and it isn’t known how many of the participants may have had epilepsy.
Of those receiving the first vaccine, 0.5% reported a COVID-19 infection after being vaccinated but before receiving the second vaccine dose.
Of people receiving two vaccines, 0.2% later tested positive for COVID-19.
The study found:
Does COVID-19 vaccination increase seizure risk in people with epilepsy?
Studies have not shown significant increases in seizure frequency after vaccination.
At the European Epilepsy Congress, Steinhoff reviewed four studies focused on seizure risk and COVID-19 vaccination in people with epilepsy. The studies showed no significant risks for seizure increases after vaccination:
A 2021 study from Germany included 54 people with epilepsy who had the first dose of one of the mRNA vaccines (Astra Zeneca, Moderna, or Pfizer/Biontech). One person had a seizure the day after the vaccination, and one person experienced a new seizure type the day after the vaccination. If both events are considered vaccine-related, the vaccine-related seizure event rate was 3.7%.
A 2022 study from Turkey included 178 people with epilepsy, most of whom were fully vaccinated with the Pfizer/Biontech vaccine. The data showed no statistically significant risk of seizure increases between vaccinations or after each vaccination. Most of this group had generalized epilepsies, and the small percentage (2.2%) of people who had seizure increases also experienced fever.
A study in Kuwait involved 111 people with epilepsy; 82 were vaccinated and 29 were not. Of those vaccinated, 6.1% reported a seizure increase after a vaccine. The relative risks for seizure increases were very small: 1.027 for the first Pfizer/Biontech vaccine; 1.019 for the second Pfizer/Biontech vaccine, and 1.026 for the first Astra Zeneca vaccine.
A study from China, published in 2021, found no differences in vaccine-related adverse events in people with epilepsy, compared with a control group and a group of people with other chronic neuropsychiatric conditions (anxiety, depression, headache, peripheral neuropathy, sleep disorders, and several others). A seizure increase was seen in 3.9% of vaccinated people with epilepsy.
Only 42% of people with epilepsy in the China study had received at least one vaccine, compared with 93% of controls and 84% of people with other neuropsychiatric conditions.
Compared with people with other neuropsychiatric conditions, people with epilepsy were significantly more concerned about potential adverse events (53.5% vs 23.5%), and they were also concerned about interactions between the vaccination and their medication.
“Those are the same concerns our patients have here in Germany,” said Steinhoff. “That’s why we did our study.”
Seizure risks: Infection versus vaccination
Steinhoff and colleagues compared 51 people with epilepsy who had a PCR-proven COVID-19 infection and no vaccinations to 561 people with epilepsy who were fully vaccinated and never knowingly infected with COVID-19. Their work (in press in Clinical Epileptology) showed that the rate of seizure increase associated with infection (7.8%) was significantly higher than the rate of seizure increase associated with vaccination (1.4%).
“Infected patients had significantly more seizure increases than vaccinated patients,” said Steinhoff. “But even in the infected group, the increase was not too dramatic.”
Because the patient groups were not subdivided by epilepsy type, seizure type, or comorbidities, the study was not powered to determine whether COVID-19 infection led to a significant increase in seizure frequency. Its purpose was to compare changes in seizure frequency between two clearly defined groups: people who had been infected and never vaccinated, and people who had been vaccinated and never infected.
The results are “very good news” for people with epilepsy who are concerned about COVID-19 vaccination, said Steinhoff.
Communication to encourage COVID-19 vaccination
“There is good safety and tolerability of the vaccines and no increased seizure risk with vaccinations,” he said. “I give advice to get vaccinated to all of our patients, especially [higher-risk groups such as] patients with comorbidities or intellectual disabilities, as well as patients who are institutionalized.”
Addressing patient concerns about vaccination is important, said Steinhoff. Some people worry that COVID-19 vaccines could interact with anti-seizure medications.
“Epileptologists talk about [drug-drug interactions] all the time,” said Steinhoff. “People are so aware of the topic; they internalize it. If that is a patient concern, you speak about it with them.”
Cross agreed. “As clinicians, we keep talking about how people need to be aware of what medications they are on because of interactions,” she said. “The vaccine isn’t metabolized in the liver and it’s not going to interfere, but the lay person may interpret it as, ‘Something is going into my body and so I need to be worried about this.’ So we need to provide accurate information.”
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ILAE is a global organization of health care professionals and scientists working toward a world where no person’s life is limited by epilepsy.