A major public health effort next month involving thousands of health care providers, government leaders, nongovernment organizations and industry is taking the world one step closer to polio eradication.
From April 17 to May 1, trivalent oral polio vaccine (tOPV) will be replaced with bivalent oral polio vaccine (types 1 and 3) (bOPV) in 155 countries. About 126 countries also have recently introduced or will be introducing trivalent inactivated polio vaccine (IPV, also known as the Salk vaccine).Dr. OrensteinContinued use of the tOPV, which contains type 2 poliovirus, is contributing to circulating vaccine-derived poliovirus 2 (cVDPV2) outbreaks, explained Walter A. Orenstein, M.D., FAAP, in a Perspective in the Feb. 11 New England Journal of Medicine (http://bit.ly/1L6yPi6).
cVDPV2 viruses can proliferate when they are transmitted among susceptible people, resulting in mutations conferring both the neurovirulence and transmissibility characteristics of wild polioviruses.
The choreographed switch involves replacing stockpiles of tOPV with bOPV and IPV during a low season for polio over a short time period. The plan is part of the Global Polio Eradication Initiative Polio Eradication and Endgame Strategic Plan 2013–2018 (http://bit.ly/1RsfNiN).
“This is a very special effort to try and make sure we don’t generate any new circulating vaccine-derived poliovirus 2,” said Dr. Orenstein, co-author of the 2015 AAP clinical report on polio eradication (http://bit.ly/polioCR).
Routine use of oral polio vaccine containing the type 2 strain no longer is necessary in part because the last case of naturally occurring type 2 wild poliovirus occurred in 1999.
“The declaration that type 2 polio has been eradicated, it’s the first time since smallpox and only the second time in history that at least one form of virus has been eradicated in the human population,” said Dr. Orenstein, who headed the U.S. National Immunization Program from 1988-2004. Polio has been a particularly challenging disease to eradicate because there are three strains. “We should be calling it the polios,” he added.
Upon switching to bivalent oral polio vaccine, the Global Polio Eradication Initiative will deploy independent monitors to check on program performance and ensure complete removal of tOPV.
The major focus of the eradication effort is type 1, which still circulates as wild poliovirus in Afghanistan and Pakistan. Although type 3 has not been declared eradicated by the Global Commission for Certification of the Eradication of Poliomyelitis, the strain has been undetected for more than three years and may have been eradicated.Dr. Maldonado“Eventually, the plan is to phase out live poliovirus vaccines altogether. That has to be done in a stepwise approach,” said Yvonne A. Maldonado, M.D., FAAP, vice chair of the AAP Committee on Infectious Diseases. She has represented the Academy during polio containment policy planning and at World Health Organization global partners meetings on ongoing eradication efforts, and has dedicated most of her career to studying the disease and polio vaccines.
To be able to certify complete eradication, criteria must be met that involves a minimum of three years without detection of the virus in the presence of certification standard surveillance and laboratory bio-containment measures for wild poliovirus.
“The Academy supports efforts around global vaccine advocacy and especially using polio as an example of how vaccines can help eliminate diseases that impact children,” Dr. Maldonado said.
The infrastructure built to achieve polio eradication and the lessons learned will help world health leaders tackle future health burdens on a global scale, not unlike how measles elimination was a major driving force for building the National Immunization Program in the U.S., Dr. Orenstein said.
“The wonderfulness of eradication,” he said, “is that it protects people forever in the future so that in essence it is a gift from our generation and all the generations involved to all future generations.”
How U.S. pediatricians can help end polio
- Make sure patients are immunized against polio. Ask patients about travel plans and give boosters to patients traveling to polio endemic countries (Pakistan and Afghanistan), http://wwwnc.cdc.gov/travel/.
- Advocate with the Academy and local Rotary International chapter for government support of polio eradication.
- Consider volunteering for the Centers for Disease Control and Prevention Stop Transmission of Polio teams, which complete short-term assignments around the world, www.cdc.gov/globalhealth/immunization/stop/index.htm.