MMRV increases the risk of febrile seizures 7-10 days post vaccination by 2, as compared to separate vaccines (MMR and varicella).
MMRV increases the risk of febrile seizures by 7.6 times, MMR+V by 4 times, and MMR separately by 3.7 times. (USA)
MMRV increases the risk of febrile seizures by 6.5 times, and MMR+V by 3.3 times. (Canada)Risk of febrile convulsions after MMRV vaccination in comparison to MMR or MMR+V vaccination. 2014, Schink, Vaccine
The same was found in Germany, where a different vaccine was used (Priorix-Tetra). MMRV is associated with a four times increase in the risk of febrile seizures as compared to MMR, and 3.5 increase as compared to MMR+V.Vaccines for measles, mumps and rubella in children. 2012, Demicheli, Cochrane Database Syst Rev
Cochrane's systematic review of MMR efficiency and safety. The vaccine efficacy is 95% against measles and 88% against mumps.
The vaccine increases the risk of aseptic meningitis by a factor of 14-22 (Urabe and Leningrad-Zagreb strains), the risk of febrile convulsions by a factor of 4-5.7, the risk of thrombocytopenic purpura by a factor of 2.4-6.3.
The authors conclude that clinical and post-clinical safety studies of MMR are largely inadequate and that it is not possible to separate the role of the vaccine in preventing disease from the side effects it causes.
They recommend improving the format and reporting of clinical and post-clinical trials, and standardizing the side effects definitions. It is also required to test the longevity of MMR protective effect.
A study of the side effects of MMR in Iran (43,000 vaccinated children). 1.8% of the vaccinated contracted mumps as a result of the vaccination. Two suffered encephalopathy and two more had anaphylactic shock. That is, the risk of encephalopathy and anaphylactic shock is about 1 in 20,000, rather than "one in a million", as usually claimed.
The risk of convulsions (not febrile) was 1 in 2,000 vaccinations in infants. The risk of febrile seizures was 1 in 1750.
The risk of febrile seizures in infants under 12 months of age who received DTP vaccination was 9.3 times higher on the day of vaccination than in children who weren't recently vaccinated.
The risk of febrile seizures in those who received MMR vaccination was 2.8 times higher during period of 8-14 days after the vaccination.
In another study, the risk of febrile seizures after MMR was 6 times higher. Similar studies: , ,