We report the case of a child presenting with nonfebrile seizures 6 and 13 days after the first vaccination with a measles, mumps, rubella, and varicella (MMRV) combination vaccine. Measles virus RNA was detected in the patient’s serum, throat, and urine.
An 11-month-old boy was presented to the pediatric unit after experiencing three seizures in the morning of the same day.
There was no history of seizures before or any other known medical conditions. Six days before the seizure, the first vaccination with the regular measles, mumps, rubella, and varicella (MMRV) vaccine (Priorix-Tetra; GlaxoSmithKline) was performed. In the meantime, there were no signs of infection or fever.
A cranial magnetic resonance scan revealed no pathological findings.
After an unremarkable hospital course, a fourth seizure episode occurred on the 13th day after the vaccination, while the child was still in the hospital.
[T]he child was discharged on the 9th day of hospitalization.
In a blood sample taken 3 months after the vaccination, high antibody values against mumps, measles, and rubella viruses were found, but no antibodies against varicella- zoster virus could be detected.
Most vaccines used today are based on the Schwarz vaccine strain.
Besides a local reaction at the site of injection, fever, and rash, the most common neurologic adverse events are febrile seizures, commonly 7 to 10 days after vaccination. Febrile seizures in general have a favorable outcome and are not associated with neurologic sequelae.
While a higher risk for febrile seizures was observed with the MMRV combination vaccine than with the MMR vaccine, nonfebrile seizures in association with MMRV or MMR vaccination have not been described so far.
Therefore, a search was performed in the database of the German Federal Institute for Vaccines and Biomedicines… and two further cases were revealed.
In the first case, a 9-year-old male experienced convulsions leading to hospitalization 14 days after he had received the second dose of MMRV (MMRVaxPro; Sanofi Pasteur MSD).
[T]he patient was discharged after 2 days of hospitalization.
The second case was an 11-month-old female who presented with a tonic-clonic seizure, allergic reaction, and exanthema 1 day after having received an unspecified dose of MMRV…
Further seizures without fever in the same child occurred on two more occasions, two and three days after having received vaccinations… against diphtheria, tetanus, pertussis, Haemophilus influenzae type b, hepatitis B, poliomyelitis (Infanrix hexa; GlaxoSmithKline), and Streptococcus pneumoniae (Synflorix; Glaxo- SmithKline)…
So far, it is not possible based on these cases to assess a causal relationship between nonfebrile seizures and vaccination.
Even though live attenuated measles vaccines have been used for more than 40 years, data are scarce on the extent to which vaccine virus replicates in or is shed by vaccinees. Isolation of infectious vaccine virus from the blood and pharynx of vaccinated children by propagation on canine renal cell culture was successfully performed in early studies with the Edmonston strain, from experimentally vaccinated Cynomolgus monkeys after vaccination with the Schwarz vaccine strain…
For the Schwarz vaccine strain, there are two case reports about healthy children that describe demonstration of vaccine virus in the throat of a 3-year-old boy and detection of vaccine virus RNA in the throat and urine of a 14-month-old child. The first child presented with fever, pharyngitis, and adenopathy 8 days after vaccination. MeV was isolated in cell culture from a throat swab taken 4 days after fever onset. The 14-month-old child in the second case report presented with facial erythema without fever 5 days after vaccination, followed by fever and rash 8 days after vaccination.
Schwarz vaccine strain RNA is present in blood at least at day 6 postvaccination and is detectable in throat and urine at days 7 to 15 postvaccination.