Africa Declared Free of Wild Polio
In August 2020, the World Health Organization's African regional certification commission announced that all 47 countries in its African Region were free of wild poliovirus. The declaration came four years after the last known case of wild polio on the continent, in northern Nigeria in 2016. It was a milestone in one of the largest public health campaigns in history, and it left wild polio endemic in only two countries, Afghanistan and Pakistan.
Polio is a highly infectious disease caused by a virus that spreads mainly through contaminated water and the fecal-oral route. It attacks the nervous system and can cause irreversible paralysis, most often in young children. Effective vaccines had been available since the 1950s and 1960s, first the injected vaccine developed by Jonas Salk and then the oral vaccine developed by Albert Sabin. Wealthy countries largely eliminated the disease, but in much of Africa routine immunization was patchy. In 1988 the World Health Assembly launched the Global Polio Eradication Initiative, backed by WHO, UNICEF, Rotary International, and the US Centers for Disease Control and Prevention, and later joined by the Bill & Melinda Gates Foundation. At that time, polio paralyzed hundreds of thousands of children each year worldwide.
Progress in Africa was uneven. South Africa and other countries pushed forward with mass immunization days, and Nelson Mandela lent his support to the "Kick Polio Out of Africa" campaign in the 1990s. Yet setbacks followed. In 2003 and 2004, rumors and distrust led some northern Nigerian states to suspend vaccination, and the virus spread to a number of neighboring countries. Conflict, displacement, and insecurity, including attacks by Boko Haram in northeastern Nigeria, later kept children out of reach. Health workers, many of them local volunteers, went door to door, and some paid with their lives in attacks on vaccination teams in several countries.
The certification followed years of surveillance, in which laboratories tested stool samples from children with sudden paralysis across the region to confirm the virus was truly absent. Nigeria, once the heart of the problem, was an important part of the achievement. Commentators noted that the same networks of health workers, laboratories, and community outreach had also helped respond to Ebola and other outbreaks.
The announcement was not the end of the story. Africa still faces outbreaks of vaccine-derived poliovirus, a rare form that can emerge in under-immunized communities where the weakened virus in the oral vaccine circulates long enough to regain the ability to cause paralysis. Because of this, officials stressed that high vaccination coverage must continue. Even so, Africa's certification stands as only the second time a WHO region has been declared free of a disease through such efforts on this scale, alongside the global eradication of smallpox in 1980, and it is often cited as proof that coordinated vaccination can overcome serious obstacles.