In 1946, the Minnesota State Fair was canceled because of fear that the crowds could cause the polio virus to spread more rapidly throughout the state and the country. In 1952, nearly 58,000 cases of polio were reported in the U.S. — 3,145 people died, and 21,269 developed paralysis. Almost everyone knew someone affected by polio. This is no longer the case in the U.S., but it is still true in many parts of the world, where the struggle to eradicate polio was initially less successful.

The Global Polio Eradication Initiative (GPEI) was founded in 1988 with this purpose in mind. The partners include Rotary International, the World Health Organization (WHO), UNICEF, the U.S. Centers for Disease Control and Prevention (CDC), and the Bill and Melinda Gates Foundation. When the GPEI was first launched, there were more than 350,000 cases of polio in 125 countries across the globe. Little by little, one country at a time, this list of polio-endemic countries has shrunk to only two: Pakistan and Afghanistan. However, two weeks ago, Nigeria, which had been polio-free for over two years, reported two new cases of polio.

This news is not completely unexpected, but great progress has been made. In 2016, there have been only 21 cases of polio reported worldwide. However, detecting polio in the environment is still crucially important, since only one in 200 people infected with the polio virus will develop the acute flaccid paralysis that makes the disease easy to identify.

People who lived through polio epidemics in the U.S. will remember that it was often just a few members of the community who were diagnosed with polio, while many others might have had intense flu-like symptoms but recovered fully and were never taken to a hospital for testing. This is what has just happened in Nigeria. There were no reported cases of acute flaccid paralysis, but the polio virus was still circulating in the environment and through the bodies of unvaccinated children, without causing an acute case of paralysis. Until vaccination rates in the region reach a sufficient level, there is still a danger that the virus could make a comeback.

The polio virus is resilient. Of the three types originally found in the world, there has not been a case of wild Type 2 polio since 1999, and this strain of this virus is now eradicated. There has not been a case of Type 3 since November 2012, indicating this strain of the virus has been eradicated as well. This leaves just Type 1. Intensive vaccination campaigns are underway in Nigeria, and will soon be underway in the neighboring countries of Chad, Cameroon, Niger and the Central African Republic to protect against further spread of the disease.

Similar outbreaks have taken place elsewhere, for example, in 2010 in Tajikistan, where a drop in vaccination activities led to a surge of 400-plus cases. When intensive vaccination campaigns were conducted at the national and regional levels, the outbreak was stopped, and Tajikistan has not had a case of polio since that time. Efforts to finish the job of eradicating polio in Nigeria are complicated by the insurgency of Boko Haram. However, the GPEI has had repeated successes in conflict zones from Sierra Leone to Sri Lanka to Liberia, and most recently in Syria in 2013. The government of Nigeria is fully committed to finishing the job of polio eradication and has pledged to further intensify its efforts.

To learn more about this global effort, go to endpolio.org. If you are interested in learning more about what is being done in your community, search for a local Rotary club at Rotary.org.

Charles Adams Cogan is a former Peace Corps volunteer (Togo, West Africa) and an associate dean of admissions at Carleton College in Northfield. He also is co-chair of the PolioPlus committee of Rotary District 5960 and has led teams of Rotarians for polio vaccination work in West Africa.