MercolaWatch:Dangerous reasoning about the chickenpox vaccine

In an April article, "Despite Doctor's Order, School Bans Girl for Not Getting Chickenpox Vaccine", Mercola is at it again with strange logic which seems to directly contradict the available facts. It seems that like many who are anti-vaccine, the idea of risk vs reward is lost on Joe Mercola. He would rather have a near-universal viral infection with frequent hospitalization and, sometimes, death than a low risk vaccine which has proven itself in the almost 10 years since it was introduced.

The article starts off with the story of a young girl who's parents opted to not get her the chickenpox vaccine (the numerous other vaccines she would presumably have been required to have aren't mentioned) because her baby sister might have inherited an unspecific immunodeficiency issue from her mother. Apparently this is based on the policy of her pediatrician to "not administer to children in families with infants as they could contract vaccine strain infections". So possibly the infant's condition was not even relevant.

But the logic here seems to be exactly backwards. According to the CDC, "varicella incidence among infants, a group not eligible for varicella vaccination, declined by 90% from 1995 to 2008". It would seem that getting the vaccine is the best thing the older sister (who is out and about among the other kids, risking exposure) could do for the younger one. But the Mercola article, nor his source, provide enough details on the specifics of the girl's case.

Mercola then proceeds to question the need for the vaccine in the first place.

He admits that before 1995, there were an average of 100 deaths per year (50 of the children) resulting from Chickenpox (varicella). In his words, "hardly a dire, life-threatening childhood disease". Tell that to parents of the 50+ children who died each year. Let's compare those deaths with the VAERS (Vaccine Adverse Events Reporting System) data that Mercola cites of 14 deaths near the time of vaccination over a period of three years. Note that is source for this is a study (Wise 2000) that actually finds the varicella vaccine to be safe after analyzing the VAERS data. That is less than 5/year, or 20x less than the 100/year pre-vaccine availability. And that's granting that there is good reason to think the 14 deaths were actually caused by the vaccine, which does not seem to be a well-supported hypothesis.

The study has a full case report of 5 of the 14 and nearly all 5 had either a history of medical complications or had a pre-existing case of varicella. As the study authors note

Where autopsy and other follow-up data were available, investigations of reported deaths often disclosed clear causes unrelated to vaccination, including malignancies, wild-type VZV, respiratory syncytial virus, and echovirus.

Keep in mind, this is from the study that Mercola himself used as a reference!

Mercola cites the 14 deaths (and 6500 or so "adverse events") in VAERS as if their presence means the deaths where necessarily caused by the vaccine. I've discussed VAERS before and the brief summary is that it is a voluntary reporting of reactions that occur shortly following vaccination. Occasionally "signals" are detected of actual risks in some populations, but the vast majority of events are actually unrelated to the vaccines (i.e. they are mere coincidences). But the data is there to be better safe than sorry. Non-specialists like me, or anybody in the anti-vaccine crowd, really should not be looking directly at the VAERS data and hope to extract meaningful data from it.

But for the sake of argument, let's grant that the numbers are accurate. Let's say that there were actually 6500 events. According to the study, 4% or about 250 were considered "serious". The study covered 3 years, so an average of about 80 serious events a year. Let's assume all serious cases resulted in hospitalization. Compare this with the 12,000 or so people hospitalized per year prior to the vaccine (according to the CDC link above). Post-vaccine, there are 1000 or so per year. The 80/year "linked" to the vaccine would be < 10% of the serious cases caused by the disease itself.

Again, according to the CDC (emphasis mine):

Chickenpox (varicella) used to be very common in the United States before the chickenpox vaccine became available in 1995. In the early 1990s, an average of 4 million people got chickenpox, 10,500 to 13,000 were hospitalized (range, 8,000 to 18,000), and 100 to 150 died each year. Most of the severe complications and deaths from chickenpox occurred in people who were previously healthy.

They go on to state that there has been a 98.5% decline in deaths of children and adolescents, and a 63% decline in death of HIV-infected children.

It is frankly mind boggling that its not clear that the benefits vastly outweigh the risks.

REFERENCES

Wise, Robert P., Marcel E. Salive, M. Miles Braun, Gina Terracciano Mootrey, Jane F. Seward, Lisa G. Rider, and Philip R. Krause. "Postlicensure safety surveillance for varicella vaccine." JAMA: the journal of the American Medical Association 284, no. 10 (2000): 1271-1279.

CDC. "Monitoring the Impact of Varicella Vaccination". Updated August 30, 2012. Visited May 2013.