Another Step Toward Polio Eradication
Reported October 17, 2008
Orlando, Fla. (Ivanhoe Newswire) — A polio vaccine that targets just one strain of the virus may offer more protection than the older, more comprehensive vaccine, new research shows.
A recent study published in the New England Journal of Medicine shows when the monovalent type 1 poliovirus vaccine is administered at birth, it offers better resistance to type 1 polio than the vaccine which targets all three strains of the virus.
Researchers administered the monovalent vaccine to one group of infants and the trivalent vaccine to another group. After thirty days, infants in the monovalent group exhibited a 55.4 percent rate of seroconversion, or antibody development, whereas infants in the trivalent group showed a 32.1 percent rate. After seven days, a significantly lower proportion of infants in the monovalent group shed the type 1 poliovirus.
Previous research has suggested the newer vaccine is two to three times as immunogenic as the older vaccine, even when administered at lower potency levels.
Roland W. Sutter M.D., M.P.H.T.M., of the World Health Organization in Geneva, Switzerland, says he hopes this is another step toward the worldwide eradication of polio. Between 1988 and 2005, the number of cases of polio decreased by more than 99 percent.
Its much easier to go from zero to 99 percent than from 99 percent to zero percent, Dr. Sutter told Ivanhoe. Theres lots of research underway so we can get to the finish line with polio eradication.
Although type 2 polio has been eradicated, types 1 and 3 still linger in Afghanistan, Pakistan, India and Nigeria. A separate vaccine that targets only type 3 polio is in clinical trials. Dr. Sutter said he hopes the newer vaccine will be used in immunization campaigns in affected countries to interrupt transmission of the virus.
SOURCE: Ivanhoe interview with Roland Sutter, M.D., M.P.H.T.M.; New England Journal of Medicine, 2008;359:1655-1665