Severe, even life-threatening peanut allergies afflict 3 million people in the United States alone. The only protection now available is to avoid peanuts and their derivatives. While it's easy to eschew peanut butter sandwiches, who's to know if the chips at the office party were fried in peanut oil? Houston-based Tanox has begun human testing of a once-a-month injection to protect the peanut-averse from accidental exposure. The drug, Hu-901, is an antibody that blocks the immune reaction responsible for swelling and itching. People taking it probably won't be able to eat nuts daily, but they should have more time to get help if they do eat those chips.

If Hu-901 is effective in preventing peanut allergies, Tanox may investigate its use against other food allergies. The company hopes a similar antibody to treat seasonal allergies and asthma will get regulatory approval by mid-2001.