Statistical Bamboozlement with Shingles Vaccines

The portrayal and effectiveness of the Shingrix shingles vaccine, focusing on its marketed efficacy and the reality of its benefits and costs. The main point of discussion revolves around the interpretation of statistics presented by health organizations and media outlets, particularly the 90% effectiveness claim often seen in marketing.

1. Efficacy Claims:

The Shingrix vaccine is marketed as being 90% effective in preventing shingles, a claim derived from relative risk reduction from clinical trials.

However, this figure can be misleading as it does not accurately reflect individual risk. In fact, while the percentage reduction is significant, it is based on low baseline incidence rates of shingles, resulting in only a small actual benefit.

2. Understanding Relative Risk:

In trials, shingles occurred at a rate of 3.4% in the placebo group and 0.3% in the Shingrix group. The reduction from 3.4% to 0.3% was labeled as a “90% drop”, conveying a sense of major impact.

The real difference amounts to just a 3.1% lower incidence, indicating that to prevent one case of shingles, you would need to vaccinate about 32 people.

3. Misleading Statistics:

The numeric representation often leads to a misinterpretation. Many may understand “90% effective” as implying very high individual protection, whereas it is more accurately a statement of relative efficacy.

The longer-term risk of getting shingles is relatively low: approximately 0.3% to 1% annually for those over 50.

4. Costs of Vaccination:

The cost of the Shingrix vaccine is substantial. It can total around $400 for the two doses without insurance. This cost translates to approximately $12,800 to prevent one case of shingles and $132,800 to prevent one case of postherpetic neuralgia, a painful complication.

With 125.5 million Americans over 50, vaccinating this population could incur a cost exceeding $1.6 trillion, raising questions about the economics of widespread vaccination for a disease that most will not experience.

5. Side Effects:

Vaccinations can also lead to adverse effects. Between 11 to 25 vaccinated individuals may experience significant side effects from the vaccine, outweighing the benefits for many.

There is also a slight, albeit rare, risk of developing Guillain-Barré syndrome, adding further risk to the vaccination conversation.

6. Media Representation:

Media outlets, like the New York Times, sometimes promote vaccine benefits without critical analysis, leading to inflated perceptions of vaccines' effectiveness while downplaying potential harms.

7. Public Perception of Risk:

Many individuals may overlook probability when considering vaccination advantages, often swayed by personal anecdotes rather than statistical realities. This can lead to different health decisions that may not be based on personal risk or benefit.

The discussion around the Shingrix vaccine highlights significant discrepancies between marketed efficacy and actual statistical realities. While the vaccine offers some protection, the absolute risk reduction might not justify the costs and potential side effects for many individuals over 50. This analysis reinforces the importance of critical consumption of health information and transparency regarding public health messaging. Vaccination decisions should consider individual risk factors, overall costs, and potential benefits against the backdrop of statistical realities. 

https://brownstone.org/articles/statistical-bamboozlement-with-shingles-vaccines/