Snoozing yet? It's dry and it's what I'm typically complaining about on Twi.tter when I bemoan the fact that I'm writing yet another report. A lot of engineering judgement along with data goes into the final number, and dots on a chart are the result of groups of engineers and geologists gathering for several days to
Full disclosure of my inherent bias: I vaccinate my kids on the recommended schedule, and all mine and S's vaccination boosters are up to date.
Anyway, as we were stuck in a traffic jam of ridiculous proportions, I took the time to read through an FD.A vaccine insert and my brain started to flex its risk analysis muscle as percentages and number of cases per 1,000 jumped out at me on the reported studies included in said insert. I began to wonder:
From the package insert: Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a vaccine cannot be directly compared to rates in the clinical trials of another vaccine and may not reflect the rates observed in clinical practice. Vaccine-related adverse reactions reported during clinical trials were assessed by the study investigators to be possibly, probably, or definitely vaccine-related and are summarized below.
Where people tend to focus on vaccine safety is in the fractions of percent of extreme reactions. To get to those reactions, we have to look at the post-marketing reports of adverse reactions, which are not the same as a controlled clinical trial where various variables are normalized to isolate the actual effect of the vaccine. These are the reported adverse reactions post-marketing:
- various infections including measles and varicella
- blood and lymphatic disorders
- immune system disorders (anaphylaxis, allergic reactions)
- psychiatric disorders (agitation, apathy, nervousness)
- nervous system disorders like afebrile convulsions or seizures, Bell's palsy, Guillain-Barre, encephalitis, to name a few
- Eye disorders
- Ear pain
- Vascular disorders
- Respiratory disorders like bronchial spasm, pulmonary congestion, rhinitis, sinusitis
- Gastrointestinal disorders
- Skin disorders
- Musculoskeletal like arthritis, pain of hip leg or neck, swelling
- Reproductive system and breast disorders - epididymitis (whatever that is)
- General disorders and site conditions - the usual shots suck and hurt kind of reactions.
- Encephalitis and encephalopathy: these occur at approximately 1 per 3,000,000 doses. That's 3x10-7.
- Death: This has been reported, but a causal relationship has not been established in healthy individuals. In other words, it's so rare, that they can't even come up with a 1 in x-million doses kind of number. They do have recommendations against getting vaccinated if the immune system is compromised in specific ways so as to avoid death.
- Chronic joint symptons (rubella vaccine) specifically: In children 0-3% and short durations. The older you are, and if you are an unlucky woman, then it can be an issue for longer periods of time and (12 to 26% of adult women)
- SSPE (subacute sclerosing panencephalitis) in children 1 case per 1,000,000. That's 1x10-7.
- Aseptic meningitis has been reported to the Vaccine Adverse Event Reporting System. No causal relationship has been shown between the particular mumps vaccine used and this reaction. (there is a causal relationship between other strains of mumps vaccine and this reaction)
- Thrombocytopenia (low blood platelet count) has been reported - tends to get worse in individuals who already have it, and if someone gets it because of the vaccine, then they may develop it more readily with follow-up doses. This is a case by case evaluation of an individuals reaction. No data is provided on how often it occurs, which leads me to believe that there isn't enough statistically relevant data to come up with a number.
- Herpes zoster (shingles) related to VARI.VAX : does not appear to exceed that of previously determined occurrence in a study of healthy children who had been exposed to wild-type varicella.
- from 5-12 days after the vaccine the incidence of seizure was 0.7/1000 (7x10-4)
- from 0-30 days after the vaccine, the incidence of seizer was 1.41/1000 (1.4x10-4)
What Jumps out at Me
Now the really interesting thing to me in comparing these two package inserts (what I could find in online research) is that the adverse reactions cited in the studies and follow-ups on the vaccine are so small in number and for the most part are reactions that one can recover from. If your child is allergic to penicillin, it's less sure that they can recover from anaphylaxis. There are enough of these reactions that the FDA considers it prudent to all-cap an entire paragraph in the insert that this reaction can and does occur.
The statistic I found for penicillin allergy is 1/10 of individuals are or remain allergic . That's a hell of a lot more than 1/3,000,000 cases of encephalitis due to a vaccine.
What About Everyday Risk Tolerance?
I work in the water resources business (specifically dam safety) and every project is tied to a risk analysis. The guidelines developed for risk analysis are based on typical societal tolerances for risk. In my industry it's typical to use a threshold of 1/10,000 as the threshold for individual risk (annual probability of a dam suffering a failure). That number isn't pulled out of the air exactly, but it can seem like it. It's based on historical data such as this chart from 2005. I realize this is old data, but had it readily available, plus it's not likely that it's changed a whole lot from then to now.
Compare our average level of risk of death every day from any cause to the level of risk of contracting a severe adverse reaction from a vaccination. I'll compare risk of death picked off the chart in about the 1-2 year range. Turns out, it's pretty rough being a baby as the risk of death is roughly 1/200. The risk of contracting encephalitis (as an example) from the M.MR vaccine is 1/3,000,000.
I realize that not all reactions are recorded in the voluntary database, and that yes, there absolutely are outliers.