This story reports on a study done in laboratory mice that showed a vaccine decreased the build-up of two proteins, amyloid and tau, that are associated with Alzheimer’s.
The story mentions this was a mouse study and acknowledges it isn’t the only potential avenue under study to arrest those harmful substances.
However, it gives an overly optimistic spin, using the word “promising” and playing up a speculative comment in a UT Southwestern Medical Center news release that dementia cases “could drop by half” if there’s a vaccine that delays the onset of Alzheimer’s by five years.
The story also doesn’t caution that success in animals often doesn’t translate to benefits in humans, and that other treatments targeting these proteins have not panned out. Also missing: discussions of costs and potential harms and comments from independent sources.
As the U.S. population ages, dementia is becoming more common. Millions of families are coping with a person who has a diagnosis of Alzheimer’s.
Available treatments do not prevent or cure Alzheimer’s and at best slow down the progression of symptoms for short periods. Considerable effort has focused on new treatments that seek to break down or prevent the deposition of abnormal proteins that appear to increase as memory loss progresses.
So far these new treatments have not been shown to help. Initially they were tried in individuals with advanced disease but now are being used in patients with mild symptoms as a way to prevent progression. Even here, trials have not shown positive results that are clinically meaningful.
A vaccine to “prevent” Alzheimer’s is appealing in that it works even earlier in the process, maybe even before symptoms appear. However, it isn’t clear that a vaccine will actually improve clinical outcomes.
The fact that this small study in mice led to several optimistic headlines — not just USA Today’s — reflects how desperate we are for progress. Regardless, news stories should not make a remedy sound closer and more certain than it is.
There’s no discussion of costs.
It might be difficult to estimate the cost of a vaccine that hasn’t yet been tested in humans. However, the story could have pointed out that at least some researchers have begun to consider the financial impact of treatments that are in development to slow or delay Alzheimer’s.
For example, British study released in March estimated that a hypothetical vaccine given to everyone over 50 that delayed the onset of Alzheimer’s by five years would yield a savings of about $9,000 in health, social care, and unpaid care costs over a person’s life. It estimated that the justified cost of such a vaccine, if it had to be given every two years, would be $1,175 per dose. However, those figures would drop to a lifetime savings of $2,200 and a justified cost of $293 per dose if the vaccine delayed onset of disease by just one year.
The story gives no data to describe the differences in the buildup of amyloid in the brains of mice given the vaccine versus those not given it.
A news release stated: “The latest study – consisting of four cohorts of between 15 and 24 mice each – shows the vaccine prompted a 40 percent reduction in beta-amyloid and up to a 50 percent reduction in tau, with no adverse immune response.”
Also, the story doesn’t explain whether there’s any data behind these speculative comments about potential human benefits from a researcher:
“If the onset of the disease could be delayed by even five years, that would be enormous for the patients and their families. … The number of dementia cases could drop by half.”
The story states that the vaccine is “safe in mice” and alludes to the fact that it hasn’t been proven safe in humans. It also mentions “harmful side effects, such as brain inflammation” with a previous Alzheimer’s vaccine attempt.
For that, we’ll give the story credit. But we think it could have better served readers by explicitly cautioning that safety in mice doesn’t translate to safety in humans.
This is a significant weakness.
The story did report that the study was in mice, but didn’t given much information beyond that about how the study was conducted. The vaccine was given to mice at risk for developing an amyloid deposit, while a similar control group didn’t get the vaccine. At 20 months, the amounts of amyloid buildup in the brains of the two groups were compared.
It does not point out that many vaccines and drug therapies have been successful in mice and later were proven unsuccessful in people.
The story also misses a key point: treatments that seek to limit build-up of harmful protein — which the story refers to as “promising” — have thus far not shown much benefit in humans. The story should have cautioned that it’s unclear a vaccine can actually prevent dementia, even if it safely limits protein growth.
No disease-mongering here.
The story has no independent sources. The authors asserted no conflicts in the published paper.
The story says the vaccine is among “several promising treatments” aimed at reducing the buildup of proteins associated with Alzheimer’s. It could have also mentioned that another Alzheimer’s vaccine is undergoing clinical trials.
It could have also mentioned current available medicines that have a very modest, short-term effect. Drugs called cholinesterase inhibitors have been approved by the FDA to lessen symptoms from Alzheimer’s, but none is curative.
The story makes clear that the vaccine is not available and has not even begun clinical research in human patients. However, it would have been appropriate to give a sense of the time frame. Even if trials started in humans and the vaccine was shown to be safe and effective, it would be years before this became widely available.
It’s clear that a vaccine would be a new approach to Alzheimer’s.
This story barely goes beyond the contents of a UT Southwestern news release, which contains more guarded and accurate language than the story.