Each year the Financial Post holds its junk science week.  This year, the media outlet is on its "16th annual" event, "dedicated to exposing the scientists, NGOs, activists, politicians, journalists, media outlets, cranks and quacks who manipulate science data to achieve their objectives."  The "standard definition is that junk science occurs when scientific facts are distorted, risk is exaggerated and the science adapted and warped by politics and ideology to serve another agenda."

I generally find junk science week at the FP reasonably informative, highlighting some flaws in areas of scientific study that warrant more critical public discussions.  But occasionally, there are some problems in what is considered "junk science."

Lawrence Solomon has an article in this year's edition on the highly controversial topic of vaccinations, with his thesis that "mass vaccination advocates rely on 'herd immunity' to make their case. But it doesn't exist."  Solomon uses measles as his example case of mass vaccination, and this is where the problems begin.

The measles vaccination program has an undeniable track record of success.  That isn't to say there aren't problems with the measles vaccination program – because there are, albeit often published anecdotally with difficult to verify datasets – but these need to be balanced against the positive benefits of the program during the past 50 years.

Several statements in Solomon's article need further examination, such as this one:

Unlike childhood measles, adult measles is dangerous: 25% of cases require hospitalization.

Childhood measles isn't dangerous?  This is an absurd claim.  In a 2004 paper from The Journal of Infectious Diseases, Walter Orenstein and Robert Perry from the Centers for Disease Control and Prevention and Neal Halsey from the Johns Hopkins Bloomberg School of Public Health provide the following table showing "Complications by age for reported measles cases, United States, 1987-2000."

Yes, the rate of hospitalization for adults acquiring measles is about 25 percent.  But the rate for children under 5 years of age is 26 percent, and the rates for the 5-9 and 10-19 years age classes are 9 percent each.  That's not dangerous?  Of course it is.  Measles is especially dangerous for young children, and it is dangerous for each and every age class.  The data on this is unequivocal, as the following quote from the abstract of Orenstein et al.'s article illustrates:

Forty years after effective vaccines were licensed, measles continues to cause death and severe disease in children worldwide. Complications from measles can occur in almost every organ system. Pneumonia, croup, and encephalitis are common causes of death; encephalitis is the most common cause of long-term sequelae. Measles remains a common cause of blindness in developing countries. Complication rates are higher in those <5 and >20 years old, although croup and otitis media are more common in those <2 years old and encephalitis in older children and adults.

Another problematic statement in Solomon's article:

The dangers extend to infants who, as USA Today points out, are too young to be vaccinated. These entirely helpless members of 'the herd' depend on antibodies inherited from their mothers. Yet previously vaccinated mothers have few antibodies to pass on, depriving their babies of protection. The only tried-and-true way for mothers to safeguard their infants – those most at risk of death from measles – remains nature's way: by ensuring that the mother had previously contracted natural measles.

In fact, herd immunity – so elusive today – fully existed prior to the vaccine's introduction. Virtually 100% of the population then contracted measles, typically as children, giving everyone lifelong immunity – and future mothers the means to protect their offspring. In mass vaccinating us, scientists of the 1960s didn't realize that infecting us with the measles vaccine – a weak version of the natural measles virus – would give us a weak version of the defenses our bodies develop to the real thing.

We need the public to be clear that infants can – and are – vaccinated against the measles. As the Department of Health and Human Services tells us, infants are usually vaccinated against measles at 12 months of age, and during outbreaks or even in the case of traveling abroad, infants as young as six months can be vaccinated.

And I thought Solomon said that childhood measles isn't dangerous.  If childhood measles isn't dangerous, then who cares if children under 6-12 months of age aren't vaccinated, or if they lack antibodies passed on from their mothers who had contracted "natural measles"?  The arguments are contradictory: on the one hand, childhood measles isn't dangerous, and on the other, we should fear infants contracting measles.  Using Solomon's logic, we should be encouraging young children to get the measles – since this grants them subsequent "lifelong immunity."

Of course, this is all ridiculous.  Measles is dangerous in all age groups, and especially those under 5 years of age, and while the mother contracting measles may offer a short-term benefit to her offspring early in their life, this needs to be weighed against the higher measles mortality rates that would occur across all age classes if we didn't vaccinate for the measles and just let all mothers acquire it at some point over their pre-child-bearing years.

The answer to this cost vs. benefit question will be found in the historical trends of measles mortality rates before and after vaccination was introduced in the early 1960s.  And the results are not in doubt.  The following graph shows the measles mortality rate in the United States from 1900 up to the present (the latest year with available data for measles deaths from the CDC is 2007; historical data before 1950 comes from the Vital Statistics Rates in the United States for the 1900-1940 and 1940-1960 periods).

The mortality rate decreased from about 1910 to the 1950s because of improved nutrition, sanitation, and health care for those who acquired measles, but the trend had essentially flatlined in the years before the measles vaccine was introduced.  In the four years after the introduction of the vaccine, the mortality rate dropped by 95 percent, the same level of decline it took 65 years to achieve in the pre-vaccine era.  Since vaccines were implemented, the mortality rate has declined by more than 99.9 percent, and in a number of recent years, the rate has been zero.

If we extend the mortality rate reduction trend from the pre-vaccine era out to the present, it appears that current mortality rates are at least two orders of magnitude lower than they would be had vaccination not taken place.  Thus, the proof is in the pudding.

While having measles does confer subsequent lifelong immunity, this cannot be conceived as a net benefit, since contracting measles leads to a significant risk of death and about a 30 percent risk of serious complications.  Overall, the time trends of measles mortality rates before and after vaccination programs were put in place proves that any minor risks from a lack of maternal immunity transfer to young infants is more than offset by a large margin by the reduction in deaths from preventing large numbers of people of all ages from contracting measles.

And that peak in measles mortality from 1989 to 1991 further highlights the efficacy of vaccination.  As described by Hinman, et al. in another 2004 article from The Journal of Infectious Diseases, "during 1989-1991, a large measles epidemic occurred in the United States and highlighted inadequate vaccination coverage among preschool-aged children. After this outbreak, enhanced efforts to increase vaccination coverage resulted in virtual elimination of indigenous measles transmission."

In the early 1960s, before measles vaccination was implemented, there were – on average – more than 400,000 measles cases in the United States each year, and this rate was approximately stable dating all the way back to the early 1900s.  Since 2000, the number of cases per year has ranged between 37 and 212 and averaged just 82 per year.  That is a reduction in the incidence rate of 99.995%, due entirely to vaccination.

So how do these massive declines in both measles incidence and mortality rates square up against Solomon's claim that "in mass vaccinating us, scientists of the 1960s didn't realize that infecting us with the measles vaccine – a weak version of the natural measles virus – would give us a weak version of the defenses our bodies develop to the real thing"?  They don't.  Measles vaccination has been a stunning public health success, not just in terms of a reduction in mortality, and also a massive reduction in the number of non-fatal negative health impacts from the measles.

Solomon argues that "the Public Health Service considered measles generally benign in the pre-vaccine era."  Not likely.  Orenstein, et al. write the following about the non-benign nature of measles immediately before vaccination began in the mid-1960s:

From 1956 to 1960, an average of 450 measles-related deaths were reported each year (~1 death/1000 reported cases), compared with an average of 5300 measles-related deaths during 1912-1916 (26 deaths/1000 reported cases). Nevertheless, in the late 1950s, serious complications due to measles remained frequent and costly. As a result of measles virus infections, an average of 150,000 patients had respiratory complications and 4000 patients had encephalitis each year; the latter was associated with a high risk of neurological sequelae and death. These complications and others resulted in an estimated 48,000 persons with measles being hospitalized every year.

With 450 deaths, 48,000 hospitalizations, 150,000 respiratory complications, and 4,000 cases of encephalitis each year due to measles just prior to vaccine implementation, could the Public Health Service really have considered measles "generally benign in the pre-vaccine era"?  Undoubtedly not.  In the late 1950s, 48,000 Americans were being hospitalized each year from the measles.  Today, on average, less than 100 Americans get the measles each year – and obviously a much smaller number are hospitalized from it.  The health cost reductions from that alone are immense.

Solomon concludes his piece by stating unequivocally that measles is a "generally harmless and beneficial disease."  It strains credulity that anyone in the 21^st century can look back at the historical harm caused by measles and refer to it as a "generally harmless and beneficial disease" in a major media outlet.  There are no net beneficial aspects of measles, and with its high rates of complications and even still significant fatality rates among those who contract the virus, it is far from "generally harmless."

Within this context, there are valid concerns regarding some potential negative impacts from vaccination, but these problems must always be contextualized within the large harm reduction offered by mass vaccination programs.  It is junk science, and dangerous public health policy, to consider only current claimed (often unverified) side-effects without explicitly balancing these issues against the clear historical and current benefits.  Being skeptical of science is healthy, but it can go too far when the skepticism includes an ignorance of the facts.