According to a University of Calgary study, a single-shot vaccine that is used for toddlers to protect them against measles doubles their risk of fever-induced seizures, compared with using two separate vaccines.
Febrile seizures usually affect children from 6 months to 5 years old with a high body temperature and a temporary lack of consciousness.
The study looked at 227,774 one-year-old children from Alberta, Canada, who received either the measles, mumps, rubella, and varicella (MMRV) vaccine or the previously separate two vaccines known as MMR+V between the years of 2006 and 2012.
With MMRV, 3.52 additional seizures were found to occur for every 10,000 doses in the 7 to 10 days after vaccination, double the seizures that occur after an MMR+V vaccine.
In 2010, a U.S. study of ProQuad—a drug similar to Priorix-Textra, which is used instead in Canada, found a higher rate of febrile seizures. This study led to an opt-in system where parents have to request the single shot MMRV vaccine.
MMRV was introduced in 2010. In the following two years, 86% of infants studied received that form of vaccine, compared to the 0.2% who received MMR+V.
According to Dr. Shannon MacDonald, a fellow at the University of Calgary’s Faculty of Medicine, a common view is that administering both doses in one arm could be triggering a stronger immune response. She says this is not necessarily a bad thing, as studies have shown a higher level of the vaccine in the blood means a stronger reaction and that it increases the body’s ability to fight the disease.
The following facts were taken from the Centers for Disease Control and Prevention:
The more people who are vaccinated, the more people that are immune to a particular disease and there are fewer opportunities for the disease to spread.
Vaccine-preventable diseases are still present everywhere in the world. More than 350,000 cases of measles were reported from around the world in 2011, with outbreaks in the Pacific, Asia, Africa, and Europe. In the same year, 90% of measles cases in the U.S. were associated with cases imported from another country.