Consequences of Neglecting Epidemiology by Global Polio Eradication Initiative

Global Polio Eradication Initiative (GPEI) was assigned the task of eliminating polio in low income countries in Africa and Asia. GPEI did not apply epidemiological guidance in designing vaccination tactics while aiming to achieve the laudable goal of ‘no child ever should get polio paralysis’. The force of infection of polio was even higher than that of measles, evidenced by its younger age distribution. Epidemiology taught that a vaccine of very high vaccine efficacy (VE) was required to prevent polio in vaccinated infants. GPEI chose to use trivalent oral polio vaccine (tOPV) exclusively (ignoring its very low VE in low income countries of Africa and Asia), instead of inactivated poliovirus vaccine (IPV) that has very high VE. The reasons were ease of giving and low cost. While every epidemiological observation pointed to respiratory transmission of wild polioviruses, GPEI maintained it was faecal-oral, ostensibly to justify the promotion of OPV. Consequently, eradication of poliovirus type 1 is yet to be achieved; type 3 was eradicated 12 years beyond target; only type 2 could be eradicated before the set target year of 2000. These delays could have been avoided by using IPV (with or without OPV). When using vaccines, not only VE but also safety had to be assured. GPEI ignored the safety problems of OPV. During the last 22 years vaccine-virus has caused polio outbreaks in 34 countries, the epidemiological warnings of which had been ignored by GPEI. Vaccine viruses are genetically unstable and regain virulence and transmission efficiency – the two properties that were minimised by attenuation. The many thousands of children paralysed by vaccine viruses remind the promoters and donors of GPEI that their goal ought to be that every child is hereafter protected from polio by giving just 3 doses of IPV.