The world is fast approaching the largest globally synchronized project in the history of vaccines. Between 17 April and 1 May 2016, every country in with world using the oral polio vaccine (OPV) will switch from the trivalent vaccine (tOPV), which protects children against all three types of the virus, to the bivalent vaccine, which protects children against type one and three. Now that type two wild polio has been declared eradicated, this is an essential part of the work that needs to be done to secure a polio-free world by phasing out oral polio vaccines to prevent future outbreaks of vaccine-derived polioviruses. This is especially significant because the type2 virus was responsible for 90% of the vaccine-derived polio cases.
As of 2 February 2016, 156 countries have introduced the inactivated polio vaccine (IPV) into their routine immunization systems, to help boost immunization against all strains of polio and to ensure that children have some baseline immunity against type two following the switch as a risk mitigation measure. This means that 81% of the global birth cohort is receiving IPV. This is the result of the largest coordinated vaccine introduction history! All countries are expected to introduce IPV by the end of 2016; countries are being prioritised for introduction based on their level of risk for polio outbreaks.
The World Health Organization has released a series of excellent short videos that lay out the plans, the reasoning, how risks will be addressed and how we will keep every child safe from polio forever. Click here to view them. News from The Global Polio Eradication Initiative (GPEI)