An updated and expanded study of “super lice” in the Journal of Medical Entomology confirms every parents’ worst fear: super lice are everywhere, and almost completely resistant to standard OTC products. Super lice are those that are resistant to chemical-based lice treatments such as RID and Nix; the result is higher failure rates for these products than ever before.
Here are the highlights from the study (the actual study is linked below):
~ Super lice have been found in 48 states (no samples were taken from Alaska and West Virginia).
~ The resistance rate is 100% in 42 of the 48 states.
~ The average resistance rate for all 48 states is 98.3%
~ Current effectiveness of permethrin -based products (the chemical used in RID and Nix) is shown to be as low as 25%. Since 1998, the effectiveness has gradually decreased from essentially 100% to current levels.