Medicine usually progresses in incremental steps. One antidepressant or cholesterol-lowering drug follows another with only marginally improved therapeutic benefit. Vaccines are different. Disease prevention through immunization, whether for polio or mumps, has the potential to transform medical practice, sometimes eliminating illness altogether. Smallpox is now (we hope) confined to heavily protected freezers in Russia and at the Centers for Disease Control and Prevention in Atlanta.
Vaccine developers appear to be on the verge of another remarkable achievement. Two vaccines that are nearing approval by the Food and Drug Administration in the U.S.–one from Merck, the other from GlaxoSmithKline–have demonstrated in clinical trials that they can prevent infection from the two types of the human papillomavirus (HPV) that account for up to 70 percent of cervical cancers. That could make a big dent in a disease that is the second most common malignancy affecting women worldwide and that kills more than half of its victims. In the U.S., in excess of 10,000 women contract invasive cervical cancer annually and nearly 4,000 die of the disease.