New research suggests a combination of polio vaccines could be more effective than just one.
A research team found administering the Salk inactivated poliovirus vaccine (IPV) alongside the Sabin live-attenuated oral poliovirus vaccine (OPV) boosted patients' immunity, the American Association for the Advancement of Science said. The finding could help speed up the eliminations of
"This study revolutionized our understanding of IPV and how to use it in the global eradication effort to ensure children receive the best and quickest protection possible from this disease," said senior author Dr. Bruce Aylward, assistant director-general for Polio, Emergencies and Country Collaboration at the World Health Organization (WHO).
"IPV should be used to accelerate the eradication of the virus in populations that have limited access to vaccination," added Dr. Hamid Jafari, WHO's director for polio operations and research and the lead author of the report. "The study has also provided the evidence for use of IPV among travelers to limit further international spread of the virus."
Since the polio vaccine was developed in the 1950s OPV has generally been the go-to.
"This is because OPV has a superior ability to induce mucosal immunity, is easy to administer requiring no needles, and is substantially cheaper," said Caroline Ash, a senior editor at Science.
Scientists have been debating whether OPV or IPV should be used in high-polio areas. Mucosal immunity decreases significantly after OPV use, causing patients to need several doses of the vaccine; OPV can also lead to the virus being further shed in the stools.
IPV has been known to close several immunity gaps, so researchers looked at whether or not a combination of the two treatments would be effective.
The researchers conducted a randomized clinical trial on 1,000 infants and children in Uttar Pradesh, India. Each subject was given one vaccine or the other, after four weeks all of the participants received a dose of OPV. The children who were given IPV proved to be less infectious than the other group. A dose of IPV boosted intestinal mucosal immunity more effectively than an OPV shot.
"The answer is now very clear," said Dr. Roland Sutter, WHO's coordinator for research and product development, polio operations and research. "Both vaccines complement one another and should be used to interrupt the final chains of transmission to attain a polio-free world in the most rapid and effective way possible."
"The global eradication effort is at a critical crossroad," continued Dr. Jafari. "Endemic polio is increasingly geographically restricted to populations in insecure and inaccessible areas. Yet the virus in these areas persists with incredible tenacity and threatens the increasingly vulnerable populations in polio-free countries with weak or conflict-affected health systems."
