Ongoing transmission of polio in India, despite high coverage with multiple doses of vaccine, continues to pose a challenge to efforts to global eradication of the disease. Now, new research by scientists in England, India, and Switzerland helps explain the disease's persistence in India and suggests strategies to eliminate the virus there (Grassly et al. Science. 2006;314:1150-1153).
Using a computer model, the researchers found that high population density and poor sanitation in 2 Indian states aid transmission of poliovirus and compromise the efficacy of the trivalent vaccine, which contains weakened versions of the 3 types of poliovirus. However, a targeted campaign using a more specific monovalent vaccine in those high-density areas should boost the vaccine's efficacy enough to quickly eliminate polio in India, the researchers said.
Stephenson J. Quashing Polio in India. JAMA. 2006;296(23):2791. doi:10.1001/jama.296.23.2791-d