Do You Really Need a Flu Shot? Don’t Ask NPR!

Introduction

On December 20, 2019, NPR published an article by Tara Haelle purporting to provide information to help people decide whether they should get the influenza vaccine annually. Instead of empowering readers with the knowledge they need to meaningfully exercise their right to informed consent, however, the article presents misleading and outright false information intended to persuade people to comply with the flu shot recommendations of the Centers for Disease Control and Prevention (CDC).

The NPR article was originally titled “Do You Really Need A Flu Shot? Here’s How To Decide” and has since been updated to read “Here’s Why You Really Need A Flu Shot”. Its central message is that everyone should comply with the CDC’s recommendation, which is that everyone aged six months and up, including pregnant women, should get a flu shot every year.

The goal of advocating public vaccine policy, however, is incompatible with the alternative goal of objectively providing people with the knowledge they need to make their own informed choice. The transparent purpose of this NPR article is not to educate but to advocate, including by demonstrably misinforming readers about what science tells us about the safety and effectiveness of influenza vaccines.

In short, as is typical for mainstream media reporting on anything related to vaccines, this NPR article is not journalism but propaganda.

Misrepresenting the Science on the Flu Shot’s Effectiveness

The first core message that Haelle delivers to her readers is that getting a flu shot guarantees a benefit. She tells her readers that it’s “never too late to benefit from a flu shot, even into December and January”.

She cites effectiveness estimates that aren’t particularly impressive. Last flu season, it “hovered around 44 percent overall; it was about 59 percent effective for young children and just 16 in adults over 65.” She then adds, “But even that low number for older adults elides how much death and disability the vaccine prevented.” In older adults, she states, “the flu shot prevents the loss of quality of life that can result from influenza complications”.

She goes on to explain how the influenza virus is “a master of adaptation” and so is “frequently a few steps ahead of scientists”, including those at the World Health Organization (WHO) who make an educated guess each year about which strains of the virus are most likely to be circulating. Each season’s flu shot is different. This year’s quadrivalent vaccine contains “two influenza A strains (an H1N1 strain and an H3N2) and two B strains. The two B strains are the same as last year’s formulation, but this year’s H1N1 and H3N2 vaccine strains are different from last year, based on recommendations from the World Health Organization.”

Tacitly acknowledging that the effectiveness estimates she cites are unimpressive, Haelle asserts that “any protection is better than none”.

However, it is simply not true that getting a flu shot guarantees that you’ll receive a protective benefit, and it is not true that without vaccination your immune system can offer no defense against influenza.

In fact, last season’s flu shot provides a useful illustration of a lack of benefit. As Mike Stobbe reported for the Associated Press (AP) on June 27, 2019, the vaccine was ineffective against the strain of influenza that was circulating most widely toward the end of the flu season. As the AP article’s lead paragraph states, “The flu vaccine turned out to be a big disappointment again.” The “again” is because the flu shot is often highly ineffective due in large part to a mismatch between the strains included in the vaccine and those that are circulating among the population.

The estimate at that time was that the vaccine’s overall effectiveness was down to just 29 percent because the strain of H3N2 circulating was a mismatch to the strain included in the vaccine. As Stobbe reported, the shot “was virtually worthless during a second wave driven by a tougher strain, at just 9%.” The CDC acknowledged that the vaccine offered “no significant protection” against that strain.

In fact, the CDC’s own preliminary estimates indicated that people who’d gotten the flu shot may have actually had an increased risk of infection with the circulating strain of H3N2. The 9 percent effectiveness cited by the AP referred to the estimate for all H3N2 strains from one of the networks the CDC uses for this purpose. Results from a second network showed an effectiveness of 13 percent. Results from a third network, however, showed a vaccine effectiveness against H3N2 strains of negative 43 percent.

The CDC’s interpretation of these conflicting results was that the three networks combined “identified no vaccine protection against predominant H3N2 virus this season”. There was “No significant protection against H3N2 illnesses likely due to emergence of antigenically different A(H3N2) clade 3C.3a”.

Haelle does not provide a source for where she obtained the estimates she presents, but it was evidently the CDC. Presently, the CDC webpage providing information about the effectiveness of the flu shot’s effectiveness for the 2018 – 2019 flu season cites a study published in the Journal of Infectious Diseases on October 30, 2019. But the data from that study does not show an overall vaccine effectiveness of 44 percent, as Haelle claims. That number rather refers to the shot’s effectiveness specifically against the 2009 pandemic H1N1 strain of influenza. The overall vaccine effectiveness was far lower, at just 29 percent.

Haelle makes a similar mistake with her claim that estimated effectiveness among children was 59 percent. Once again, that refers to effectiveness against the included H1N1 strain for children aged six months to eight years. The overall effectiveness for that age group against any strain was lower, at 48 percent.

Likewise, contrary to her claim of 16 percent overall effectiveness for adults over age 65, the actual estimate for that age group was only 12 percent.

Overall effectiveness of the vaccine against the emergent H3N2 strain was just 5 percent.

Moreover, as the study authors pointed out that, while the results did not reach statistical significance, the age-specific estimates against the emergent H3N2 strain were negative for adults aged 18 to 64 years, indicating “higher odds of influenza among vaccinated compared with unvaccinated” patients.

In other words, while possibly due to chance, the data suggest that adults who got the flu shot last season were at an increased risk of infection with the emergent H3N2 strain.

As the study authors remarked, “The evasion of immunity through rapid evolution and accumulation of changes in major surface proteins of the A(H3N2) virus is a challenge for influenza vaccine strain selection and production.” The data suggest that “vaccination did not significantly reduce medically attended influenza illness due to A(H3N2) virus infection.”

Misreporting the numbers and ignoring the data indicating negative effectiveness of the vaccine against the emergent H3N2 strain aren’t the only problems with Haelle’s suggestion that getting a flu shot guarantees at least some benefit.

For starters, there are at least 200 known viruses that cause what are broadly termed “influenza-like illnesses”. Frequently, what doctors diagnose as “the flu” isn’t caused by the influenza virus at all, but by some other virus that the vaccine offers no protection against. (The only way to confirm influenza infection is with laboratory testing, which isn’t usually done.)

While the vaccine is designed to offer some protection against some strains of influenza A and B, all types of these strains represent only about 10 percent of circulating viruses known to cause flu-like symptoms.

Furthermore, according to a CDC study published in the journal Vaccine, only about 8 percent of the US population on average is infected with influenza during any given year.

Far from conferring at least some benefit for everyone, a systematic review of the medical literature published in February 2018 found that “71 healthy adults need to be vaccinated to prevent one of them experiencing influenza”.

To put it another way, most people who get a flu shot are placing themselves at risk of harm from the vaccine despite the unlikelihood that it will confer a benefit. (The only adverse events Haelle acknowledges are “headache, nausea, low fever or similar symptoms” that resemble those caused by the virus itself. She otherwise insists on the safety of the vaccine, which we’ll come to.)

In addition to the vaccine’s “modest” impact, according to that review, “the effects of inactivated vaccines on working days lost or serious complications” remains “uncertain”.

A prior systematic review had found “no evidence that they affect complications, such as pneumonia, or transmission.”

Its authors also warned that the findings of a modest protective effect must be interpreted in light of the inclusion of studies funded by the pharmaceutical industry because, unsurprisingly, studies have shown that industry funding tends to bias results in favor of product under study.

That prior review, published in 2010, also specifically criticized the CDC for deliberately misrepresenting the science in order to support its flu shot recommendations.

Instructively, it is the routine habit of journalists to turn to the CDC for their information about flu shots, which they then relay to readers as though credible despite the fact that the CDC has been shown to misrepresent the science in pursuit of its public policy goals.