Denise VanDomselaar’s letter of Wednesday, June 25 tried to make a big deal out of the fact that Alberta Chief Medical Officer Dr. James Talbot’s letter didn’t include the apparently Earth-shattering statistic that "young children who received the vaccines separately had less than 0.2 per 1,000 incidents of febrile seizure.
“For those children who received the MMRV vaccine, the seizure rate went up to 0.352 per 1000."
If we wanted to be sensationalist, we could point out that the difference between 0.0002 (that’s what 0.2 per 1,000 works out to) and 0.000352 (that’s what 0.352 per 1000 works out to) is the equivalent of a 76 per cent increase. Which is totally huge, right?
Well, no … no it’s not that huge. It means that if we gave 10,000 people the MMRV vaccine, we might expect to observe febrile seizures in three of them, or possibly four. Let’s double things to smooth out that decimal: if we gave 20,000 people the MMRV vaccine, we might expect to observe febrile seizures in seven of them.
If we gave another 20,000 people the vaccines separately, we might expect to observe febrile seizures in four of them. This is what we are talking about here: the difference between four and seven people in a group the size of the population of Fort Saskatchewan.
Is there an increase in the number/rate of febrile seizures? Yes.
Is this increase correlated with the use of the MMRV vaccine? Yes.
Is this a reason to stop giving our children the MMRV vaccine? No.
What Ms. VanDomselaar omitted mentioning was the interpretations of the researchers who performed the study, which are as follows: "[d]espite an increased risk of febrile seizures following MMRV (compared with MMR+V), the absolute level of risk was small. Policy-makers need to balance these findings with the potential benefits of administering the combination vaccine or determine whether the choice of vaccine rests with clinicians and/or parents."
What are the potential benefits of administering the combination vaccine? Mostly, it means that there’s less pain involved for children (since they receive fewer shots overall). It’s more convenient for parents, as well. And it allows for vaccines to be deployed more cost-effectively, which is no small consideration in our always cash-strapped health care system.
And if we forego the measles vaccine? Currently, the mortality rate from measles in Canada has been very low … less than 0.1 per 1,000 cases. Before we had a vaccine, as near as I can calculate, the mortality rate was about 0.214 per 1,000 cases, possibly higher. So in our population of 20,000 from before, that would work out to about four deaths. Okay, still pretty low … less than the number who might experience MMRV-related febrile seizures, in fact.
But then, febrile seizures are rarely fatal, and don’t typically recur. Get vaccinated.
Kenneth Kully, St. Albert