With Latest Success In Africa, We're One Step Closer To Eradicating Polio

Vaccines Work, And Africa Is Proof

Vaccine-Strain-Polio-Infections-Outnumber-1
BADRU KATUMBA/Getty

On August 25, 2020, after four years without a single case, the Africa Regional Certification Commission declared the entire continent of Africa free of wild-strain polio. This is amazing news for the beautiful continent and for the scientific community. Vaccines work, and the children of the world are safer because of it.

The initiative to eradicate polio in Africa has been ongoing since 1996.

This campaign, called Kick Polio Out of Africa, was initiated by Nelson Mandela and supported by Rotary International. Before it began, wild polio still paralyzed 75,000 children each year in Africa. According to the WHO, from 1996 to today, an estimated 1.8 million wild polio cases were averted, and 9 billion oral vaccine doses were provided to 220 million children by 2 million volunteer vaccinators. This campaign was wildly successful.

In order to combat the polio problem, children in Africa mainly received the oral polio vaccine, or OPV. OPV is a live attenuated vaccine. That means it contains a whole but weakened form of poliovirus.

It comes in the form of oral drops. Unlike the injected inactivated vaccine we use in the United States, OPV can be administered by someone without medical training. The oral vaccine made mass vaccination efforts, including door-to-door campaigns, possible. It’s why we have hope of seeing polio disappear forever.

OPV’s effectiveness is indisputable, but it does come with one drawback.

In places with low vaccine uptake and sanitation inadequacy, there is a risk of a vaccine-derived polio outbreak. Contrary to what a lot of anti-vaccine advocates would have you believe, vaccine-strain polio does not happen to a recently vaccinated person. It doesn’t even happen to a person who comes in contact with a recently vaccinated person.

As a matter of fact, according to the Global Polio Eradication Initiative, “For several weeks after vaccination the vaccine virus replicates in the intestine, is excreted and can be spread to others in close contact. This means that in areas with poor hygiene and sanitation, immunization with OPV can result in ‘passive’ immunization of people who have not been vaccinated.”

Shedding can actually allow unvaccinated people to benefit from immunity!

Unfortunately, this passive polio immunity has limits.

If too many people in one area are unvaccinated, the vaccine version of the weakened virus finds too many hosts. It can mutate and become virulent again.

That’s how vaccine-derived polio happens.

While wild-strain polio is completely absent from the African continent now, polio derived from a mutated form of the attenuated vaccine remains. Around 180 cases of vaccine-derived polio have been identified in Africa this year, with about 300 cases worldwide.

Wild poliovirus type 2 was declared eradicated in 2015. In 2019, The WHO declared wild poliovirus type 3 eradicated worldwide. There is still one strain of wild polio is in circulation in two countries. So far this year, there have been 37 wild polio type-1 infections in Afghanistan, and 65 in Pakistan for a total of 102 wild-type cases.

If you wanted to be intentionally deceptive, you could put that wild-type number next to the 300 vaccine-derived cases. You might declare that the vaccine is three times worse than the disease itself.

With just a few minutes of light reading, it’s easy to see that it’s not that simple.

Anti-vaxxers helped create this problem.

According to Africa Kicks Out Wild Polio, “Across Africa, vaccination efforts were hampered by pockets of vaccine refusal in the 1990s and 2000s due to rumors and misinformation. In northern Nigeria, however, this became an even bigger issue: in some northern states, polio vaccinations were stopped for nearly two years between 2003 and 2004. This unleashed a resurgence of polio cases, which rippled across the country and the rest of the continent, spawning wild polio outbreaks in 20 other African countries.”

The vaccine-derived polio problem might not even exist if anti-vaxxers hadn’t spent their time trying to convince people in developing nations that a life-saving vaccine was scarier than a disease that could paralyze or kill them.

The solution to the vaccine-derived polio problem is to continue vaccinating. The worldwide medical and scientific communities are committed to eradicating all remaining strains of polio, both wild-type and vaccine-derived. They will adjust the vaccines (as they have already been doing) to address the ongoing issue. They won’t stop until polio only exists in storage in labs. Eliminating pockets of unvaccinated people is still a priority.

Vaccination campaigns are challenging in countries where there is any kind of instability, but it can be done. When it comes to eradicating polio, humanity is already well on the way.

It’s going to take some time, but we are closer than ever.

This is why it’s important for those of us who are at least marginally science-literate to advocate for vaccines whenever we can. Anti-vaccine misinformation is not just annoying, it’s dangerous. Deadly.

Vaccines have saved millions of lives. They’ve prevented countless people from suffering.

This news about Africa is a glowing vaccine success story. With continued coordinated efforts, we could soon see the day when science gets to declare polio eradicated worldwide.