How to avoid causing polio in the name of its eradication.

WHO began immunising children against polio in low-income and middle-income countries (LMICs) in 1974, through the Expanded Programme on Immunisation, using a trivalent oral poliovirus vaccine (tOPV)—three doses during infancy. In 1984, a dose at birth was added. Polio was not controlled in LMICs despite the four-dose tOPV schedule. Hence, in 1988, WHO proposed, and the World Health Assembly unanimously passed, a resolution to eradicate polio by 2000.1WHOGlobal eradication of poliomyelitis by the year 2000.https://apps.who.int/iris/bitstream/handle/10665/164531/WHA41_R28_eng.pdf?sequence=1&isAllowed=yDate: May 13, 1988Date accessed: March 26, 2023Google Scholar In our inequitable world, aiming for equity in polio prevention was altruism that inspired everyone, particularly financial donors. Eradication meant reducing the incidence of polio to zero and interrupting poliovirus transmission, globally.2Dowdle WR The principles of disease elimination and eradication.MMWR Morb Mortal Wkly Rep. 1999; 48: 23-27Google Scholar Reaching country-level zero polio and zero poliovirus transmission is defined as elimination.2Dowdle WR The principles of disease elimination and eradication.MMWR Morb Mortal Wkly Rep. 1999; 48: 23-27Google Scholar Before 1988, Sweden, Iceland, Finland, and Norway had eliminated polio using the inactivated poliovirus vaccine (IPV), with three doses during infancy and one or more boosters later.3Böttiger M The elimination of polio in the Scandinavian countries.Public Health Rev. 1993; 21: 27-33PubMed Google Scholar Denmark achieved polio elimination using a sequential schedule of IPV followed by the oral poliovirus vaccine (OPV).3Böttiger M The elimination of polio in the Scandinavian countries.Public Health Rev. 1993; 21: 27-33PubMed Google Scholar These experiences provided proof of principle and a one-stage, rapid, polio elimination model. For achieving zero incidence of polio by 2000, the Global Polio Eradication Initiative (GPEI) should have transitioned to the IPV in LMICs and phased out the OPV, since it causes vaccine associated paralytic polio (VAPP) in an occasional vaccinated child or unvaccinated contact.4Nkowane BM Wassilak SGM Orenstein WA et al.Vaccine-associated paralytic poliomyelitis. United States: 1973 through 1984.JAMA. 1987; 257: 1335-1340Crossref PubMed Google Scholar Indeed, OPV use is incompatible with polio eradication. Several countries had achieved zero incidence of polio caused by wild polioviruses using tOPV but had to switch to IPV to avoid VAPP and reach polio elimination. This method was a slow, two-phase polio elimination model. France discontinued OPV in 1988, Germany in 1989, and the USA in 2000, all achieving elimination within 1 year of IPV switch. Unfortunately, the GPEI could not manage to end wild poliovirus using tOPV because of its well documented suboptimal efficacy in tropical and subtropical LMICs.5Patriarca PA Wright PF John TJ Factors affecting the immunogenicity of oral poliovirus vaccine in developing countries: review.Rev Infect Dis. 1991; 13: 926-939Crossref PubMed Google Scholar Thus the two-phase model was inapplicable for polio eradication. Only one tactic could eradicate polio: to introduce IPV and when 80% coverage of three doses of IPV is reached, to phase out OPV, country by country. This method required a policy shift in the early 1990s so that the industry could ramp up IPV production. Continuing use of the OPV beyond 1999, without ensuring protection from polio with IPV, has resulted in: between 8800 and 17 600 children being paralysed by VAPP;6John TJ A developing country perspective on vaccine-associated paralytic poliomyelitis.Bull World Health Organ. 2004; 82: 53-57PubMed Google Scholar sporadic polio, caused by vaccine-derived polioviruses types 1, 2, or 3, and polio outbreaks, caused by these circulating viruses, having paralysed nearly 5000 children; and wild poliovirus not yet being eliminated in Afghanistan and Pakistan where a section of society do not trust the OPV, particularly when given in repeated house-to-house campaigns. Since the future polio-eradicated world can use only the IPV, transition to IPV is the sensible way forward. This policy shift must be announced without delay so that supply, especially of combination vaccines containing IPV, can be expedited. No child is recorded to have developed polio after receiving three doses of IPV during infancy. We appeal to the GPEI, donors, and global opinion leaders, to ensure that no more polio is caused in the name of its eradication. The promised equity must be delivered. We declare no competing interests. TJJ is a retired employee of the Christian Medical College.