Looking at the impact of the rotavirus vaccine on afebrile seizures

July 5, 2018

A new report reveals that hospitalizations for afebrile seizures, as well as for gastroenteritis, have dropped since the introduction of a rotavirus vaccine in 2006.

The report, published in the Journal of Infectious Diseases, studied the incidence of hospitalizations for generalized tonic-clonic afebrile seizures associated with rotavirus.1 Hospitalizations for acute gastroenteritis have decreased since the introduction of the rotavirus vaccine, but researchers specifically sought to determine whether hospitalizations for associated seizures decreased, as well.

“In addition to the reduction in diarrhea hospitalization that occurred after rotavirus vaccine introduction, there has also been a decrease in seizure hospitalizations which highlights an important but unexpected additional benefit of the rotavirus vaccination program, says Jacqueline Tate, PhD, a rotavirus expert with the Centers for Disease Control and Prevention (CDC) and co-author of the report. “Pediatricians should continue to vaccinate eligible children against rotavirus.”

The research team used hospital records for children aged younger than 5 years to perform the study, comparing prevaccination and postvaccination discharge data. A total of 962,899 records from seizure hospitalizations were reviewed, and the research team found a decrease of 1% to 8% in seizure hospitalizations after the introduction of the rotavirus vaccine. Most of the hospitalizations noted in the report-55%-occurred in boys, and 22% in newborns. Another 14% of hospitalizations were in children aged 24 to 35 months, according to the data.

Rotavirus is a highly communicable disease spread via the fecal-oral route, and it is a common cause of acute gastroenteritis in children. The virus can cause nearly universal infection in children by age 5 years, and, prior to the development of a vaccine, was responsible for 20 to 60 deaths in the United States each year and 500,000 deaths from diarrhea worldwide, according to the CDC.

Good hygiene can help deter the spread of rotavirus. However, vaccination is highly effective, preventing severe illness in 90% of children vaccinated and all illness in 70% of vaccinated children.

The vaccine, approved for use in 2006, is typically given in the first months of life-in 3 doses at ages 2, 4, and 6 months for RotaTeq (Merck; Whitehouse Station, New Jersey), and in 2 doses at ages 2 and 4 months for Rotarix (Glaxosmithkline; Research Triangle Park, North Carolina), according to the CDC. Both vaccines are given orally and the full series ideally is completed by age 8 months.

Symptoms of infection can range from minor to severe, and often include watery diarrhea, fever, and vomiting. Children aged 3 months to 35 months are most at risk of catching rotavirus, according to the CDC, and illness can be complicated by severe dehydration. In some cases, afebrile seizures, resulting from an enterotoxin produced by the virus, have been noted.

“Although rotavirus infection has been associated with seizures, the impact of rotavirus vaccination on the risk of seizures in children had not been extensively studied following rotavirus vaccine introduction,” Tate says. “The reduction in seizure hospitalizations following rotavirus vaccine introduction in the United States was an unexpected but important additional benefit of the vaccination program and supports continued routine rotavirus vaccination.”

In a commentary on the study published by the American Academy of Pediatrics, Bud Wiederman, MD, MA, champions the findings of the study, but cautions against drawing large-scale conclusions for clinical practice.2

“The authors performed an excellent analysis and discussion. They found a drop in seizure-associated hospitalizations after rotavirus vaccination was introduced, compared to the period before: from 388/100,000 in the years 2000-2006 to 382/100,000 from 2008-2013 in children between the ages of 0 and 59 months, a result that reached statistical significance,” Wiederman notes in the commentary. “The drop was primarily in ages more affected by rotavirus infections, occurred during the rotavirus season, and was more evident as vaccine coverage increased over the years, all lending support to their findings.”

However, Wiederman cautions clinicians about promoting the rotavirus vaccine for seizure prevention.

“Should pediatric healthcare providers be ‘selling’ rotavirus vaccine as protecting children from seizures? Let's assume the study findings are true. In that case and using the rates above, the seizure rate in the first 5 years of life dropped from 0.388% to 0.382%,” Wiederman notes. “We can easily develop a number needed to treat from that view-to prevent 1 additional seizure case in this population, we would need to immunize 100/(0.388-0.382), or about 16,700 children. That's not a great return on investment.”

Wiederman concludes that although the rotavirus vaccine is effective in reducing incidence of infection and associated seizures, it shouldn’t be marketed by clinicians as a preventive measure in pediatric seizures.

References:

1. Pringle KD, Burke RM, Steiner CA, Parashar UD, Tate JE. Trends in rate of seizure-associated hospitalizations among children <5 years old before and after rotavirus vaccine introduction in the United States, 2000-2013. J Infect Dis. 2018;217(4):581-588.

2. Wiederman B. Does rotavirus vaccine decrease seizures in children? American Academy of Pediatrics Journals blog. Available at: http://www.aappublications.org/news/2018/05/15/does-rotavirus-vaccine-decrease-seizures-in-children-grand-rounds-5-15-18. Published May 15, 2018. Accessed June 26, 2018.