Slideshow: Journey to Sierra Leone for the Debut of a Breakthrough Polio Vaccine

June 23, 2021

Sierra Leone recently became one of the first countries to roll out a new vaccine intended to reduce cases of vaccine-derived poliovirus. Clinical trials have shown that the new vaccine, called the novel oral polio vaccine type 2 (nOPV2), provides comparable protection against wild poliovirus as the original oral vaccine while being more stable, which will reduce the risk of vaccine-derived poliovirus, for reasons described below.

In 2020, all African countries were certified free of wild poliovirus. However, many are still fighting the circulation of vaccine-derived poliovirus, which occurs when the weakened live virus in the original oral vaccine reverts back to a paralytic form. In areas where vaccination rates are high enough – around 80-85% of eligible children – this does not cause a problem. But in places where vaccination coverage is low and there is inadequate water and sanitation infrastructure, this excreted vaccine virus can reintroduce poliovirus into the community and, in rare instances, lead to an outbreak of paralytic polio.

Since January 2020, there have been more than 900 vaccine-derived polio cases across 24 African countries. In Sierra Leone, the first cases were isolated in December 2020 in Kambia, Tonkolili and Western Area Urban districts. The most recent numbers show that 32 cases are now in 7 districts. The Task Force’s Polio Eradication Center has been working with Sierra Leone for the last six months to equip them for the roll out of this new vaccine.

Journey with Task Force Polio Surge Team Senior Epidemiologist Victor Eboh to learn how they do it.

A flyer taped up at a health facility in Freetown, Sierra Leone helps build awareness about the importance of getting children vaccinated.

I work with the Sierra Leone Ministry of Health and Sanitation, local partners, the U.S. CDC, UNICEF, and the WHO to ensure that the country’s polio vaccination program meets stringent safety and preparedness criteria such as adequate surveillance systems and vaccinator training.

Here, I am hosting technical meetings with the Global Polio Eradication Initiative partners and Ministry of Health and Sanitation officials leading up to the vaccination program’s launch.

Vaccinators are often field epidemiologists and community health workers who have been trained through the country’s Field Epidemiology Training Program (FETP).

I train FETP graduates and students and surveillance officers on polio vaccination and disease surveillance efforts.

Several health leaders gathered on May 28 for the official national launch of the nOPV2 vaccination campaign, including CDC Country Director Tushar Singh, U.S Ambassador to Sierra Leone David Reimer, the Minister of Health and Sanitation (MOHS) Austin Derby, and other MOHS officials.

“We are confident the vaccination efforts will be implemented with the highest quality and efficiency with the goal to reach every last child under 5 years of age with two drops of the vaccine,” said Ambassador Reimer. “Together with efficient supervision by national supervisors from the Ministry, global partners and Field Epidemiology Training Program (FETP) graduates, we are hopeful that the polio outbreak in Sierra Leone and other parts of Africa will be contained.”

During the ceremony, the U.S Ambassador and CDC Country Director administered the first drops of nOPV2.

Trained vaccinators set out daily from health facilities and go door-to-door in areas where poliovirus has been identified to find children who have not been vaccinated.