Bedding covers designed to keep dust mites out of the air don’t reduce hay fever and asthma symptoms, two studies concluded Wednesday.
The covers, which sell for $50 to $100 in the United States, screen out mites and their byproducts while allowing air to flow. They are sold as one way to help sensitive individuals reduce the risk of allergic reactions.
“The obvious implication of these studies is that mattress covers as a routine part of the treatment of asthma are not worth the price,” Thomas Platts-Mills of the University of Virginia said in a commentary in Thursday’s New England Journal of Medicine, where the two studies appear.
The studies show that the covers have little effect, at least by themselves, on a person’s symptoms, apparently because there are so many other sources of dust.
In a one-year test of 1,122 adults with asthma, British doctors found that volunteers who used the bedding had no more real improvement in their symptoms than people who used standard bedding.
The second, smaller study, led by researchers in the Netherlands, found that hay fever symptoms did not improve among the 114 people who used mite-proof bedding covers, compared to the 118 who did not.
Platts-Mills said patients who want to avoid the allergens must be far more aggressive at removing other sources of dust and dust mites.
The studies focused on bedding covers because they are easy to use and readily available, and because tougher anti-allergy strategies — such as stripping out carpeting, removing most of the furniture in a bedroom and doing rigorous regular cleaning — can be impractical.
