Junkfood Science: Children are not ferrets and other fallacies of logic

January 15, 2009

Children are not ferrets and other fallacies of logic

If you are a ferret, sticking your nose into a jar of Vicks VapoRub might make your nose run a little and irritate your sinuses.

At least that’s what we can safely conclude from a recent study on 15 ferrets. The ferrets were anesthetized and intubated. Some Vicks VapoRub had been put on the end of their endotracheal tube. Their mucociliary function was measured and found to be decreased 35% over controls and the mucous secretions increased 14% in the healthy ferrets and 8% in the ones who had their tracheas artificially inflamed. The ointment did not lead to any increase in lung congestion.

This study was conducted by pediatricians at Wake Forest University School of Medicine in Winston-Salem, North Carolina. It was published, not in a veterinary journal, but in Chest, the journal of the American College of Chest Physicians.

While few people have ferrets and children are not ferrets, why is this study being mentioned at all? It has been used to support hundreds of news stories this week scaring parents that VapoRub is dangerous and could hurt their kids. (Yes, there was a press release.) At MSNBC, for instance, readers don’t learn until eleven paragraphs into the story that “the new study” behind the “warning issued for parents” was done on ferrets.

VapoRub is one of the oldest home remedies and has been rubbed on the chests of children with colds by their moms and grandmothers since Dr. Joshua Vick and his brother-in-law created their Croup and Pneumonia Salve in 1890. The ointment is a combination of oils, petrolatum, with a little camphor, eucalyptus oil and menthol. Mothers and grandmothers don’t use it as a cure for a cold, nor has it ever been promoted as shortening the course of a cold. As far as old-time nostrums go, it’s fairly benign when used as directed (don’t heat it, eat it or put it on open sores or sensitive membranes). It might not do much to actually open up airways and reduce congestion, but the menthol can trigger feelings of relief of stuffiness and help people feel better, as Bruce K. Rubin, MD, FCCP, lead author of this study said.

The source of media warnings of a frightening link to breathing problems in infants turns out to be a story about one 18-month old little girl. She had developed a bad cold and her grandmother placed some VapoRub under her nose. About 45 minutes later, she got worse and began wheezing and was taken to the hospital. After one day in the hospital, the little girl improved enough to go home. Dr. Rubin said the ointment shouldn’t be used under age 2 or placed under the nose. He thought the child was extremely sensitive to the ointment and that it had caused her breathing problems. He launched an investigation to test the effects of VapoRub on the respiratory tracts, using ferrets.

But did you catch the fallacy of logic in that scenario?

Cautionary skepticism would be understandable based simply on the fact this was an anecdote on a single child, and that this adverse event is overshadowed by a long safety record. In a message to parents, the company said that multiple clinical studies on more than a thousand (human) children from 1 month to 12 years of age have been conducted and demonstrated the safety and efficacy of the ointment. As added safety precautions, it continues to do clinical tests. When used as directed, they’ve reassured parents that it is safe. Procter & Gamble also questioned the relevance for humans of animal studies. Children aren’t ferrets and a single animal study doesn’t translate to clinical recommendations for people.

Procter & Gamble didn’t agree that a single case report provided support to fear it was dangerous. “To say it was the Vicks VapoRub that caused the respiratory distress,” said spokesman David Bernens, “I'm not sure we have made that link yet.”

If you caught the fallacy of logic in that toddler’s story, you would agree. It exampled one of the most common logical fallacies, called post-hoc ergo propter hoc. It’s a Latin phrase that means “after this therefore because of this.”

If A happens before B, then A causes B.

This fallacy is when people conclude that because something occurred after something else, that it must have happened because of it. Just as association doesn’t equal causation, the direction of an association isn’t proof that one causes the other, either.

Her respiratory illness got worse after her Grandma used VapoRub, but that does not mean that the respiratory problems were caused by the ointment. The natural progression of her respiratory illness more likely corresponded to use of the cold remedy. At the hospital, the grandmother had been asked what she’d done that might explain her Grandchild’s breathing problems and she remembered having used VapoRub under her nose. She could just as easily remembered giving her a popsicle, her favorite stuffed teddy bear, putting her in her pajamas, turning the television on, or countless other things with no more clinical relevance.

This anecdote simply does not offer any credible support for sensationalized scares that VapoRub, when used as directed, is dangerous.

Nor does a lab study on 15 ferrets. Let’s all lighten up on the anxiety meter and use our noggins.

Veterinarians might decide to not use it for their ferrets, but zoo keepers at Paultons Park have found it very useful for their meerkats, as the Daily Mail reported:

Zoo uses Vicks VapoRub to stop meerkats fighting

Zoo keepers have come up with a ingenious way to stop meerkats from fighting - hide their scent with Vicks VapoRub. Experts at Paultons Park near Romsey in Hampshire were concerned that their two existing meerkats would fight with three new arrivals when they were introduced to the family attraction. So they came up with the plan… The product is put on the animals' noses and hides their scent long enough for all of them to get used to each other without any arguments.

"It is normally extremely difficult to integrate new meerkats into an existing group - their usual instinct is to try to attack any newcomers. "However, thanks to a suggestion from our vet, Kate Chitty, we were able to neutralise all odours by using a little of the VapoRub on the nose of each meerkat. "The meerkats then all smelt the same to each other and gladly accepted the new arrivals." The new group are now getting along famously…

But it is doubtful that this finding would apply to children, either. :-)

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