Vaccines: What do we think?

CNN published a poll on Monday of this week that contains some interesting statistics. A story announcing the poll began

A new CNN/ORC poll shows nearly 8 of 10 Americans believe parents should be required to vaccinate their healthy children against preventable diseases such as measles, mumps, rubella and polio. If the children are not vaccinated, most agree the child should not be allowed to attend public school or day care . . . 

The basic methodology and results are described here. Overall, 78% of respondents believed parents should be required to vaccinate children against preventable diseases if they are healthy. The age stratified results depict an interesting trend: Older Americans are most supportive of required vaccinations (84% of those 50+ versus 72% of those under 50) and those at the younger end of the spectrum -- and in particular, those of common childbearing ages -- are much less supportive (only 67% of those 18-34 years of age).

Pondering these statistics might lead one to muse that it would have been useful if the poll, rather than asking if parents should be required to vaccinate, had instead asked simply if parents should vaccinate. On Tuesday another poll appeared, this time by Reuters/Ipsos, that asked just that. Information on that poll can be found here. A Reuters news story summarized this poll:

Seventy-eight percent of respondents in the online survey said all children should be vaccinated unless there is a direct health risk to them from vaccination. Only 13 percent opposed vaccinations. . . 

The story went on to note that the "numbers are absolutely overwhelming in favor of vaccinations with a consistent minority in opposition." That's good, but probably not good enough. Herd immunity likely needs to be over 90% in order to eliminate measles. If the poll was representative of the larger US population, then the 78% statistic suggests that we have some work to do.

Of course, polls are not compete studies, and it's hard to know what to make of such results. However, I don't think they're entirely reassuring.

(image source: CDC)

Elimination, not eradication

In discussions of past and present measles activity in the United States, one sometimes reads that measles was once eradicated here.

It wasn't, though in 2000 it was declared eliminated.

Measles elimination is defined as interruption of continuous (i.e., endemic) transmission lasting ≥12 months. Eradication, on the other hand, implies global elimination. Smallpox was declared eradicated in 1980 and we're trying hard to eradicate polio and others at present. Measles has not been eradicated.

Eradication of measles may be possible, though there significant challenges. Sadly, despite the availability of a safe and effective vaccine, the disease continues to maintain a strong foothold in many regions of the globe. This persistence poses a threat to non-immune persons in our mobile world, as we are currently seeing in the US.

If you hear someone confuse elimination for eradication, you might gently correct them. It's important that people understand the threats to their health and wellbeing. 

(image source: CDC)

Your belief does not trump his right to recover

One story connected to the California measles episode in particular speaks to me. It concerns a dad speaking out, in defense of his son's fragile health, against the decisions of many not to vaccinate their children. The man's son is recovering from leukemia and cannot yet be vaccinated against measles. He is justifiably concerned about unvaccinated classmates posing a potentially mortal infection risk to his son and has requested that such children be barred from school.

The question of why some don't vaccinate their children (or themselves) is complex and multifaceted, but it seems to have one thing in common with other major public health issues of recent times: the idea that "it's my right to". In addition to it's my right to not vaccinate my children, we often hear that it's my right to possess assault rifles and it's my right to have raw milk on the market.

Should these be individual rights? From a public health perspective I would argue no, and point out that there's another fundamental question to be answered: Do we want to live in a society where someone's "rights" endanger the health and wellbeing of others? We've answered that question before for other major public health issues: there are mandatory seat belt laws in many states; it's not legal to drive under the influence of alcohol; and it's not legal to smoke in public areas in many parts of the nation. Such laws attempt to limit the ability of an individual to place others at risk. The dad in California has the right -- in fact, the obligation -- to protect his son's health and wellbeing. Could enacting legislation mandating vaccination except in specific medical circumstances be a solution?

I resonated with the man's concern for his son partially because cancer has touched the lives of close friends of mine. Those at risk from infection due to therapy-related immunocompromise and chronic disease are thought to number in the millions in the US. They have rights and deserve to be protected. Legislation on this issue, if possible, won't happen quickly. Pragmatically, I think we need to understand why some people believe that vaccines are dangerous when there's no evidence to support that claim and much evidence demonstrating that measles -- and other vaccine-preventable preventable diseases -- are lethally dangerous. Why are the likes of Jenny McCarthy more credible to some than the US Institute of Medicine? Understanding such issues may provide a basis for a conversation and, ultimately, change.

(image source: CDC)