Vaccine opponents have facts, too

Vaccine opponents have facts, too, they just don’t seem to base their decisions on them.

I’ve written about my time as an anti-vax mom on my other blog. I probably wasn’t the typical vaccine opponent because, while I gleaned some entertainment from the conspiracy theories, I wasn’t much of a conspiracy theorist myself. In my view, most of the anti-vaccine rhetoric hinges on either cynicism about the government or outright conspiratorial thinking.

However, I was fascinated by vaccine science– or what I knew about it as a (at the time) sophomore pursuing a biology degree. The thing is, I knew a lot of other intelligent, creative parents (mostly mothers) who were also interested in the science, the “peer-reviewed papers” that vaccine advocates so often demand, and still chose not to vaccinate their children. It isn’t always a lack of facts, or a total disregard for them that leads to vaccine rejection. More often, it seems, it’s just decision-making based on different priorities. For me, the decision was made partially on misinformation, partially on real information, and mostly on culture, emotion and superstition.

I recently wrote:

I was intrigued by the [anti-vaccine] information I was reading, especially the speculations that there wasn’t sufficient science on disease ecology and the assertion that we were somehow cheating nature in a way that would come back to bite us.

Today, this topic– microbial ecology– still captures my attention, which explains my most recent post on this blog. This is where I praise the vaccine opponents for bringing some real, and fascinating evidence into the discussion instead of the absolute woo that’s all too common. That is, the effects of the PCV vaccine on microbe colonization in the nose and throat. Even when they bring solid evidence to the table,. the knee-jerk rejection of vaccines, and mixing good science with pseudoscience and fear, is more than obnoxious. So while I’m giving credit where it’s due, I have to insist that the anti-vaccine position is still dangerously warped.

There is a lot of evidence that vaccines have prevented infections, both mild and very serious. There is evidence that individual vaccines have reduced hospitalizations from the targeted illnesses and secondary infections. An emerging topic in research is the concern that bacterial conjugate vaccines, like PCV, is the possibility that vaccines will lead to the dominance of new species of microbes that colonize the nose and throat, and new types of infections will emerge that may make the overall impact of vaccines like these quite weak. So far, this hasn’t been observed as a significant problem, although some reported cases of ear infections caused by non-vaccine strain pneumococcal bacteria and staph that made the news, implicating vaccines as a possible cause for the shift.

In the PCV references in my last post,  I pointed out that the authors in one study specifically looked for and detected no increase in disease caused by non-vaccine strains. Not only were S. pneumoniae ear infections reduced (77%), but that contributed to an overall decline in ear infections (60%) meaning that there was no apparent, clinical illness caused by niche replacement. This study was in Israel, and from the abstract alone it was unclear which other factors were controlled for, including exposure to secondhand smoke.

There are different ways of monitoring the impact of the pneumococcal conjugate vaccines. One is by monitoring the incidence of invasive disease– like meningitis, sepsis and pneumonia. Another way is to monitor the incidence of minor illness like ear infections, either in total or specifically from strains included in the vaccine. Finally, one can monitor nasal swabs to get an idea for how the vaccine impacts colonization by the bacteria strains, but not necessarily infection.

H. influenzae (Hi) vs. S. pneumoniae (Sp), as well as S. aureus (Sa) and Sp, compete in ways that may lead to one of these other pathogens to emerge and cause illness in the absence of Sp. There has been much study on this subject, and a few plausible mechanisms determined from in-vitro studies– specifically the production of hydrogen peroxide by Sp contributing to a decrease in Hib. Yet, from nasal swabs of inoculated mice, it appeared that Hi outcompeted Sp. Hard to draw a conclusion from that. Since we can vaccinate for Hib (an invasive-disease causing strain of Hi) and 13 strains of Sp, the issues of these two competing seems kind of a moot point since cases of invasive disease from both have declined (Hib disease by 99% according to CDC surveillance).

For Sp vs. Sa,  this 2004 paper showing an inverse relationship between these organisms has been cited at least 90 times, meaning there has been a good deal of follow-up research on this topic. This 2014 paper did a follow up study, and found:

Among subjects colonized with pneumococci, the number also carrying either H. influenzae or S. aureus fell during the study and at 14 days post-inoculation, the proportion carrying S. aureus was significantly lower among those who were colonized with S. pneumoniae (p=0.008) compared to non-colonized subjects.These data on bacterial associations are the first to be reported surrounding experimental human pneumococcal colonization and show that co-colonizing effects are likely subtle rather than absolute.

In 2005, children with HIV were more likely to be carriers of S. aureus than HIV-negative children. Among children with HIV, those colonized with S. pneumoniae were not more or less likely to carry S. aureus than those who were not colonized– so S. aureus infection was independent of S. pneumoniae infection.

And in 2009, parental colonization with S. aureus was found to be an important factor in whether or not children carry the bacteria.

PCV appears to have had a significant and dramatic effect on the incidence of pneumococcal meningitis, but because of its recent introduction, it’s less clear at the moment whether or not this will have an overall impact of reducing cases of invasive meningitis, given the possibility of serotype replacement or niche replacement by another bacterial pathogen. Hib conjugate vaccine, on the other hand, has been around long enough to show a reduced incidence of Hib meningitis without a corresponding increase in bacteria meningitis from other pathogens. Of greater concern, complicated pneumonia increased over time, as a subset of pneumonia cases despite the introduction of PCV7 (prior to PCV13). This increase occurred even with a drop in cases with a bacterial cause, and a dramatic drop in pneumococcal cases. The increase in cases caused by staph appeared to be linked to a surge in MRSA prevalence. Immunization status was unavailable in the study linked above. However, the WHO assessed the growing rates of empyema in Australia and found:

…the absolute increase in the incidence of hospitalizations for empyema and for viral pneumonia (3 and 70 hospitalizations more per 106 person–years, respectively) was much smaller than the absolute decrease in the incidence of hospitalization for bacterial pneumonia (623 hospitalizations fewer per 106 person–years).

The hardcore anti-vaxers apparently trumpeted the incorrect story of “pneumonia caused by pneumococcal vaccine!” I hadn’t heard of any of this until now, probably because at the time this news came out I was a terrified young mother and just seeing words like “empyema” on my computer screen would make me an anxious mess. So, I missed it. However, as a consequence of my own tendency toward panic, I do understand why vaccine-hesitant parents who read package inserts and see scary words like “thrombocytopenia” and “encephalopathy,” would be further frightened by reports that muddy the waters and make it seem like maybe newer vaccines aren’t worth it.

As interesting as this is to geeky laypersons and some fierce vaccine critics, it is of little concern to the average parent. Every study I have seen covering this topic has indicated a need for further study and more careful methods to sort it out, but none have suggested that it’s an issue worthy of frantic urgency. It certainly doesn’t warrant ditching the vaccine program in part or in whole in the name of microbiome integrity. Anyway, the Active Bacterial Core Surveillance program reaches over 42 million people in the US and monitors bacterial infections, including treatment resistant organisms. This is one of several tools in place to pick up possible shifts in infection rates. So we have time to wait for further studies while still taking advantage of the apparent benefits of PCV 13, even though the full picture is incomplete.

I mentioned that anti-vaxers have facts, too, because these niggling topics rarely come up in those pro-vax forums made up of lay advocates rather than professionals in the field. The most dismissive pro-vax individuals miss the opportunity to learn from their opponents. Vaccine critics like to think that a lack of discussion of issues like this among pro-vax warriors online is indicative of willful ignorance or blind defense of vaccines. Thus the oft-mocked “do your research!” What they’re referring to is consumer research. The anti-vaccine crowd does not produce quality, peer-reviewed research that supports their position, though they may occasionally find some and cling to it. The reality is that none of us can study and discuss every topic in depth in the way we all might like. Then, the controversy is so heated in social media that there’s little chance for a thorough, informative discussion most days of the week.

That, my friends, is why I have this blog. Here I pretend to be part of a discussion, even though there may be no one listening.

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