Is the Washington Post Accurate?

It appears that Twitter has preserved a snippet that is not present in the original article referenced in Dr. Pan's tweet. The summary claims that "lax state laws have contributed to reduced vaccination rates throughout the Pacific Northwest." However, the article notes that:

> The Pacific Northwest is home to some of the nation’s most outspoken and organized anti-vaccination activists. This movement has led to a significant drop in child immunizations in Washington, as well as in neighboring Oregon and Idaho, resulting in some of the lowest rates in the country. For instance, as many as 10.5 percent of kindergartners in Idaho are unvaccinated for measles, which is nearly double the national median.

Is this article truthful? It seems to present an "alternative fact." Let’s analyze the data further.

Vaccination Trends in Washington State

In my initial article, I provided an overview of immunization rates at both the HHS region and state levels. Now, I want to focus more closely on Washington State’s vaccination statistics. Recently, there has been increased volatility in these rates, though it's difficult to determine whether this volatility is unusual. When individuals reference a brief timeframe to argue for a "decline" in vaccination rates, it is akin to observing a few cold winters and declaring that "the Earth is cooling!" A thorough analysis should consider how current data points fit into the broader dataset.

This graph illustrates the fluctuations observed in recent years. While the 2012 anomaly may hold significance, it does not sufficiently explain the timing of the outbreak, especially since overall vaccination rates are averaged over several years, smoothing out year-to-year variations.

The Need for More Data

To draw further conclusions, we require significantly more data. Variations may exist at the county level or even smaller units. If this is the case, changes in distribution might not be captured in my analyses. However, if these small communities exist within a larger population, it seems unlikely they would significantly influence large-scale outbreaks.

An unexpected outcome has arisen from these recent outbreaks. According to Ars Technica, the surge in cases and subsequent public concern has led to a notable increase in vaccinations. Consequently, we should expect to see rising vaccination rates in forthcoming datasets, alongside a reduction in isolated cases.

Even if the source of the recent outbreaks lies outside of anti-vaccine sentiment, we should still observe a decrease in cases, as the vaccine effectively prevents symptoms. This outcome may complicate data interpretation, requiring adjustments for changes in vaccination rates to accurately assess whether the pathogen is becoming more virulent.

Analyzing Asymptomatic Infections

Given the recent outbreak and the rapid shifts in vaccination rates among certain groups, now is an opportune moment to investigate asymptomatic infections. As I pointed out in my paper on whooping cough, these infections are not well understood or studied. Although there are distinctions between whooping cough and measles, we should expect that infection rates in a random sample of the population would be significantly lower among vaccinated individuals compared to those unvaccinated. The degree of this difference could provide valuable insights into the current vaccine's effectiveness against measles.

To illustrate potential findings, I recently encountered a study regarding measles vaccination in Taiwan, which was presented as evidence for our current understanding of vaccination. However, it appeared that, based on random sampling rather than case surveys, the basic reproduction rate was not driven below one, indicating a failure to achieve herd immunity. I am currently verifying this with the authors to determine if this estimate reflects a scenario of 100% vaccination.

The contrast between the apparent "eradication" of measles in the United States and the medical community's consensus that a 95% vaccination rate should achieve herd immunity suggests that asymptomatic infection may indeed be an issue. Therefore, a comprehensive analysis across the United States is essential.

Anti-Vax Sentiment: A Closer Look

Does it make sense that anti-vaccine sentiment would lead to decreased second and third doses but not the initial doses of the MMR vaccine? One of the counterarguments to my initial analysis of measles vaccination patterns in the U.S. is that the data does not differentiate between the number of doses received. It merely indicates whether a child has received one or more doses. I initially assumed that, while my data captured the proportion of children who received at least one dose of the MMR vaccine, we could infer changes in vaccine hesitancy from this measure.

What supports this assumption? Occam’s razor and the absence of alternative explanations for why an anti-vaxxer would administer one dose of the vaccine while withholding subsequent doses, particularly when the latter doses are administered after the typical age for autism diagnosis.

That the vaccination rates for second and third doses are generally lower than those for the first dose does not undermine this argument. The assertion is that the recent outbreaks stem from a decline in vaccination rates due to anti-vaccine sentiment. Thus, while it may not be logical for the rates of all doses to align, proportional changes in these rates are reasonable. In other words, if a decrease in vaccination rates is attributed to anti-vaccine sentiment, we should observe a similar percentage decline in second and third dose coverage.

Graphical Limitations

Another point I raised in my discussions is this: repeatedly, it’s argued that although vaccination rates have remained stable on a larger geographic scale, there are localized pockets of low vaccination rates. This assertion suggests that these pockets are tightly knit at the community level. However, to substantiate this claim, we would need community-level data demonstrating a shift in vaccination behaviors.

There’s an additional complication. If we consider tightly connected communities with low vaccination rates, composed of familial and neighborhood units, we can depict the population graph as a coarser representation where each of these communities is represented as a single vertex.

The effectiveness of this simplification hinges on whether these pockets are transient or stable. If they are transient, frequently disbanding, then the simplification becomes invalid. However, the argument posits that these communities are not transient, allowing us to apply this simplification.

By treating each community as a vertex, we can assess the vaccination rate within this broader framework, as I have done, and again we find a lack of change in vaccination rates on that scale.

County Data Availability

One rebuttal is that we do possess county-level data. While we have data for certain years across some counties, to accurately analyze vaccination trends within a single state, we require comprehensive data from every county over multiple years. Observing a drop in vaccination rates in one county does not inform us whether this decline coincides with increases elsewhere. A thorough analysis must encompass all counties within a specified region over an extended period; otherwise, we risk relying on anecdotal evidence.

The Dynamics of Anti-Vax Clusters

Another issue arises from the assertion that the anti-vaccine community is a closely-knit group where individuals with similar beliefs reside near one another. If this is indeed the case, then the measles virus should naturally extinguish itself within these populations.

In a highly interconnected community, a pathogen that provides lasting immunity after infection—like measles—would swiftly circulate throughout the population, leaving only newborns susceptible. At that point, the proportion of immune individuals would approach 100%, achieving herd immunity. In essence, these communities should become almost universally immune to the pathogen following an initial outbreak.

Non-Medical Exemptions

Another concern is the reliance on non-medical exemptions (NMEs) to gauge vaccination rates. Is this assumption valid? For example, a tweet suggested that stringent vaccine laws in West Virginia shield the state from recent outbreaks, unlike Pennsylvania and Ohio with their more lenient regulations. However, West Virginia has consistently reported lower vaccination rates than Pennsylvania, while Ohio's rates have fluctuated but often exceed those of West Virginia.

Thus, it is unreasonable to depend solely on lax laws or NMEs to accurately assess vaccination behaviors.

The Burden of Proof

Finally, I want to emphasize that I do not need to substantiate my arguments. I am providing extensive data on the subject out of goodwill, but the burden of proof lies with those making claims. The medical community has attributed recent outbreaks to changes in vaccination behaviors. Aside from the challenges of proving causation, the medical community must first validate that vaccination rates have indeed altered. If the assertion is that changes have occurred at the county level, it is incumbent upon the medical community to compile county-level data and conduct a proper analysis. Until this is accomplished, we are justified in questioning the assertion of causation. We do not have to accept the claim that "changes in A have caused changes in B" if the party asserting this has not even confirmed that A has changed.