Two vaccines may be best for eradicating polio
Quashing the polio virus for good may take a belt-and-suspenders approach, a new study suggests. One in which children get not only a dose of the cheap and easy-to-administer oral vaccine, but at least one dose of the inactivated vaccine — the one developed by Jonas Salk that is predominantly used in developed countries.
That finding, reported Thursday in Science Magazine, has prompted the World Health Organization to recommend that countries that exclusively administer oral polio vaccine to its infants and children ensure those children also get at least one dose of inactivated vaccine.
Aided by war, malnutrition, superstition and mistrust of the medical establishment, the polio virus continues to resist eradication, despite the determination of the World Health Organization to consign it to the medical history books. As of 2013, polio remains endemic only in Nigeria, Pakistan and Afghanistan. But polio won’t go quietly: In recent years, polio outbreaks have occurred in countries where the disease had long been considered eradicated — in China and, more recently, in Syria.
Two excellent vaccines exist — the inactivated poliovirus vaccine developed by Salk in 1952, and the oral poliovirus vaccine developed by Albert Sabin and licensed for worldwide use a decade later. Given three doses of either vaccine, a person is almost certain to develop immunity to all three strains of polio virus.
But because vaccination campaigns are so easily disrupted by conflict, mass migrations and rumors of medical malfeasance, getting the highest level of polio immunity with the fewest vaccine doses delivered is key. So public health authorities and immunologists continue to squabble over which vaccine confers the highest levels of immunity and prevents the spread of the virus best.