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Claim that new flu vaccine delivers 40% relative risk reduction not justified

Superior Protection by Flublok® Influenza Vaccine in Seniors Documented in New England Journal of Medicine

Our Review Summary

The news release, which comes from flu vaccine manufacturer Protein Sciences Corporation, highlights a recent study published in the New England Journal of Medicine on the effectiveness of its vaccine in older adults. The news release does a fair job of describing the study, when the drug will be widely available, and addressing potential harms. However, there are two significant shortcomings: first, the release does not address cost — which is problematic, given that the release comes from the company itself; and second, the release only tells readers about the benefits of the vaccine in terms of relative risk, as opposed to absolute risk. This is an important distinction — which we’ve discussed quite a bit — and we’ll address it at greater length below. Furthermore, the release seems to inflate the reduction in relative risk from 30 percent to 40 percent. Data in the study itself only supports a 30 percent relative risk reduction.


Why This Matters

The CDC estimates that “influenza has resulted in between 9.2 million and 60.8 million illnesses, between 140,000 and 710,000 hospitalizations and between 12,000 and 56,000 deaths annually since 2010.” What’s more, the CDC also notes that: “While influenza seasons can vary in severity, during most seasons people 65 years and older experience the greatest burden of severe influenza disease.” In other words, the flu is a big deal — and especially so for older adults. This news release is focused on a study that examined the effectiveness of a new flu vaccine in adults aged 50 years and older compared to the conventional flu vaccine in adults of the same age. Even an incremental improvement in efficacy of a vaccine so commonly used and central to prevention of illness is important. This is useful information, and could help older adults — and their doctors — make informed decisions about how they choose to protect themselves against the flu. However, in order to make truly informed decisions, older adults (and their doctors) need to truly understand the difference in protection provided by the two types of vaccine — and they also need to know the difference in cost. Informed decisions can’t be made without a clear understanding of costs and benefits, and this release doesn’t quite meet the bar.


Does the news release adequately discuss the costs of the intervention?

Not Satisfactory

Costs aren’t discussed at all. Given that this release comes from the manufacturer, and that the drug was approved by the FDA in October 2016, it’s not clear why this information isn’t available.

Does the news release adequately quantify the benefits of the treatment/test/product/procedure?

Not Satisfactory

This is very problematic. The release tells readers that “People who were given [the new vaccine] Flublok Quadrivalent were over 40% less likely to develop culture-confirmed influenza [compared to those who took conventional, egg-based inactivated vaccine].” If you look at the numbers reported in the NEJM article, you’ll see that 96 of the 4303 people who received the new vaccine (or 2.2 percent) were later diagnosed with the flu. That compares to 138 of 4301 study participants who received the conventional vaccine (or 3.2 percent). So the benefit is a reduction of risk from 3.2 to 2.2 percent. That’s a 1 percentage point difference in terms of absolute risk. So where does that “40% less likely” language come from? Theoretically, it refers to the relative reduction in risk between the experimental vaccine group and the conventional vaccine group. But that doesn’t really work either. Here’s how the study authors describe the relative risk reduction in the NEJM article: “thus, in the modified per-protocol population, the probability of influenza-like illness was 30% lower with [the experimental vaccine] than with [the conventional vaccine].” So, where does that “40% less likely” language come from? We don’t know, and the release doesn’t tell us.

Does the news release adequately explain/quantify the harms of the intervention?


The release includes a section on the safety of the new vaccine that offers substantial relevant information, as well as how to obtain more detailed information if desired.

Does the news release seem to grasp the quality of the evidence?


The release includes a concise, but effective, overview of the study.

Does the news release commit disease-mongering?


No disease mongering here.

Does the news release identify funding sources & disclose conflicts of interest?

Not Satisfactory

The release is clearly from Protein Sciences Corporation and clearly identifies its own chief medical officer when she is quoted in the piece. The release does not explicitly state that the study was funded by Protein Sciences, but hat can be deduced from the text.

But omitting conflicts of interest disclosures in the release is another matter. According to the disclosure in NEJM, journal article authors “Drs. Dunkle, Izikson, and Cox report being employed by and holding stock in Protein Sciences.” That financial connection should have been included in the news release.

Does the news release compare the new approach with existing alternatives?


The release does not list other flu vaccines by name, but does clearly describe the conventional vaccine that was compared to Flublok Quadrivalent in this study. The release also articulates what distinguishes Flublok from conventional vaccines in terms of its manufacturing and components (e.g., Flublok is made without using eggs, etc.).

Does the news release establish the availability of the treatment/test/product/procedure?


The release explicitly states that: “Flublok Quadrivalent was approved by the FDA in October 2016 and will be available nationwide in prefilled syringes for the upcoming flu season.”

Does the news release establish the true novelty of the approach?


As noted above, the release clearly describes how Flublok Quadrivalent differs from other flu vaccines. The release also addresses the novelty of the clinical study in shedding light on the efficacy of Flublok Quadrivalent to a conventional vaccine in older adults.

Does the news release include unjustifiable, sensational language, including in the quotes of researchers?

Not Satisfactory

In addition to the findings that inflated the relative risk reduction from 30 to 40 percent (described under benefits), the chief medical officer’s statement includes the following: “Clearly, Flublok represents a major step forward in combating influenza on a global scale.” Stating the the findings are “a major step forward” and “on a global scale” are broad, unjustified claims. This is an incremental improvement, not a major step forward.

Total Score: 6 of 10 Satisfactory

Comments (2)

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Donald Weinshank

July 3, 2017 at 4:38 pm

We need comparison to conventional egg-based vaccine.The issue is risk analysis of different approaches. Of course, this approach may be of significant help to people who have anyphylactic shock to vaccines made in eggs,


Alison Fujito

March 10, 2018 at 8:52 pm

You might want to look more closely at the safety studies on this flu shot, and on every other vaccine. You might not be aware that vaccines are classified as biologicals, and are thus exempt from the standard of safety testing required of all other pharmaceutical products. They are not required to be safety-tested against a true placebo; typically, adverse event data is compared with either another vaccine (which may have a poor safety record itself), or with the most reactive ingredients in the vaccine, minus the actual antigen, Since the adjuvant’s entire purpose is to elicit a stronger immune response, it hardly qualifies as a placebo, but it’s usually given — sometimes in large amounts — to the “placebo” group.

Data on long-term effects, such as autoimmune and neurological disorders, is rarely, if ever, sought.