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Vaccine sharply cuts rate of shingles: study

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3 Star

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Vaccine sharply cuts rate of shingles: study

Our Review Summary

This story outperformed the HealthDay and WebMD stories on one point; in addition to reporting both the relative risk reduction (55 percent) and absolute risk reduction (from 13 to 6 cases per 1,000 people per year), it was the only one to also point out that 71 people would have to be vaccinated in order to prevent one shingles attack. The fact that this story included all three ways of looking at the results (and that the other stories included both the relative and absolute risk reduction results) may be due to the way the study authors clearly and prominently reported these complementary statistics.

But it got unsatisfactory scores for:

 

  • not discussing the limitations of the observational study;
  • not addressing potential harms;
  • not interviewing anyone who would make the point that NOT getting this vaccine is still a valid choice – a shared decision-making message that was absent.

 

Why This Matters

There is a line in this story –  “…the vaccine has not caught on as much as some had hoped” – that raises the question of whose hopes have been dashed?  The makers of the vaccine? Perhaps this vaccine is being slowly disseminated because it is too early to know what harms may arise as more and more patients in the general population receive it. It’s also important for patients to know that not everyone is destined to have zoster. The cumulative lifetime incidence is about 10-20%, with incidence rates increasing with age. The zoster vaccine appears to reduce the risk but doesn’t bring it to zero. The take-home for readers is that there’s a need for shared decision-making on this issue.

Criteria

Does the story adequately discuss the costs of the intervention?

Satisfactory

The story reports that the vaccine can cost $200.

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

Satisfactory

This story reports the apparent reduction in shingles risk among vaccinated participants in three ways:

 

  • half as likely to develop shingles
  • about 6 cases each year among every 1,000 people compared to about 13 cases per 1,000 unvaccinated people
  • vaccinating 71 people prevented one case of shingles.


Although the half-as-likely description got top billing, readers are given the results in complementary ways that help them understand just how common shingles is among the people studied and how much difference vaccination may make.
The study authors highlighted these different ways of looking at the results, thus helping journalists provide a more complete picture to the public.

This story is the only one of the three we reviewed that clearly noted that the study looked at a limited time span and that the researchers can’t say whether the effects of the vaccine persist through later years. That’s an important caveat, since a 60-year-old who had chicken pox as a child is at risk for a shingles attack for the remaining decades of life. If the vaccine cuts the risk of attacks in half, but only for the first few years after vaccination, then the lifetime reduction in risk would be much smaller.

Does the story adequately explain/quantify the harms of the intervention?

Not Satisfactory

The story does not address potential harms. This study did not report adverse events, but the clinical trial that led to approval of the vaccine reported more than a third of participants had redness and pain after getting a shot. Although the original clinical trial (partially funded by the vaccine maker) concluded that adverse events were generally mild, the story still should have addressed this point. 

Does the story seem to grasp the quality of the evidence?

Not Satisfactory

This story highlights the value of studying vaccination effects in actual practice (rather than merely under ideal clinical trial conditions), but it does not do as good as job a job as the WebMD story did in pointing out the limitations of the retrospective observational approach the researchers used. Even though the study authors prominently noted sources of potential bias and their attempts to take those factors into account, the story does not tell readers about those limitations and caveats.

Does the story commit disease-mongering?

Satisfactory

The story accurately describes the population of people eligible to be vaccinated. It notes the vaccine is not recommended for everyone over age 60, but it does not explain why some people are advised not to get this vaccine.

Does the story use independent sources and identify conflicts of interest?

Not Satisfactory

There is a source who is independent of this study; however, Dr. Oxman was the lead researcher of the clinical trial that led to the approval of this vaccine. The description of him as being “involved in a previous study of the vaccine” is inadequate to describe his perspective on this vaccine. This story also fails to tell readers about study funding (from the Kaiser Permanente health plan) or support that the vaccine maker has given to some of the researchers for other research projects.

The comments from Dr. Oxman dealt only with benefits of vaccination. The story would have been better if there had been independent comment on the study itself, both what it adds to what we know and what potential weakness or limits there are in this sort of study. There’s still a strong shared decision-making message that should be the take-home, but that didn’t come across in the story – perhaps because of who was interviewed.

Does the story compare the new approach with existing alternatives?

Not Satisfactory

While there are reports of links between stress and shingles outbreaks, there is no alternative that has been studied to the extent that vaccination has. However, given the high cost of the vaccine (for people without generous insurance coverage) and other practical hurdles to vaccination, and then the relatively small risk of an attack (about 1 percent per year in unvaccinated people), it would have been helpful to see some discussion of the relative priority of shingles vaccination for most older people.

Overall, as noted above, there is still a valid choice NOT to get this vaccine, yet that perspective did not appear in the story as an alternative.

Does the story establish the availability of the treatment/test/product/procedure?

Satisfactory

The story notes that this shingles vaccine was approved in 2006. It also makes reference to stringent requirements for storage and handling, which have been cited (along with cost) as barriers to access.

Does the story establish the true novelty of the approach?

Satisfactory

The story makes clear that this vaccine is the only approved shingles vaccine and that it has been available in the United States since 2006. It also makes clear that this study provides information about how the vaccine performs in the real world, as opposed to the idealized conditions of a clinical trial.

Does the story appear to rely solely or largely on a news release?

Satisfactory

The story does not appear to rely on a news release.

Total Score: 6 of 10 Satisfactory

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