ABOVE: World Health Organization

Update (May 18): Health officials in Mozambique have declared a polio outbreak after confirming a case in the country's northeastern Tete province. Viral sequencing information indicates that the virus circulating in Mozambique is closely related to the poliovirus circulating in Pakistan as recently as 2019.

On Monday (March 21), the East African nation of Malawi will launch the first of four rounds of a large-scale polio vaccination campaign in an effort to stop the devastating virus from spreading further, according to STAT

In February, a 4-year-old girl who lives outside of the country’s capital, Lilongwe, was diagnosed with type 1 polio and became paralyzed as a result of her infection. The case was the country’s first in three decades and the first on the continent since 2020. According to STAT, the poliovirus likely made its way into Malawi from Pakistan, one of only two countries where polio is still endemic. Officials determined that the child did not catch polio during travel to Pakistan, meaning that the poliovirus was likely circulating in Malawi. 

Polio is a devastating virus. It spreads quickly and easily between children through fecal matter but causes few or no symptoms in many. But one out of every 200 who are infected become permanently paralyzed, and some die. There is no cure. 

Zambia, Mozambique, and Tanzania will join the first round of Malawi’s mass vaccination campaign next week, and jointly plan to vaccinate 9.4 million children over four days. Zimbabwe is scheduled to join later rounds, expected to begin in May and June, Modjirom Ndoutabe, the polio coordinator in the World Health Organization’s Regional Office for Africa, tells STAT. By the end of the campaign, organizers hope to administer 80 million doses of the bivalent Oral Polio Vaccine and immunize 23 million children under the age of 5, according to a WHO press release. The goal of the campaign is to reach children that are only partially immunized or who have never been immunized. The WHO recommends that children get four doses of the vaccine over the first six years of their lives.  

Officials tell STAT that they are taking a multinational approach to curb polio’s spread because the borders among the four nations see a considerable amount of traffic. The paralyzed girl was not diagnosed with polio until three months after her illness began, which could have given the virus time to spread. 

“We cannot know really the magnitude of the problem. Is this virus spreading already in those countries or not?” Ndoutabe tells STAT. “So adding Zimbabwe, it’s just to be sure that we can handle broadly the situation and not allow polioviruses to spread in the other countries.”

See “For Polio, Two Vaccines Work Better Than One

Janet Kayita, the WHO’s acting country representative for Malawi, tells STAT that the details of the large, coordinated effort are already being hammered out. The vaccination campaign will target all children under the age of 5, regardless of their previous vaccination status. In this campaign, 70,000 vaccinators will go door to door to give children a dose of an oral polio vaccine, reports The Jerusalem Post. This effort will be repeated again in April, May, and June.

“It’s huge. It’s huge. For Malawi alone, the under-5 population is … about 2.9 million,” Kayita tells STAT. “It’s a huge health system-wide effort by everybody over four days. Repeated four times. Four rounds. So it’s a massive, massive effort.”

Kayita tells STAT that the confirmed case in Lilongwe launched an investigation that involved interviewing the affected child’s family members and tracing their contacts. Officials have also made efforts to track any cases linked to the outbreak and monitor the virus in wastewater. Malawi officials have already established 11 surveillance sites in four cities across the country to monitor transmission and analyze environmental samples for polio, according to the WHO press release. No other confirmed cases have been reported. 

Malawi’s polio vaccination rates are typically above 90 percent, reports STAT. But the coronavirus pandemic and lockdowns have stunted vaccination efforts against polio and other diseases. The pandemic has also made surveillance of diseases more difficult. In some districts, Kayita tells STAT, the vaccination rates are under 80 percent. The girl in Lilongwe was incompletely vaccinated for polio, having received the first dose at birth but not the other doses necessary to be fully vaccinated.

See New Oral Polio Vaccine to Bypass Key Clinical Trials

Malawi’s vaccination push faces several challenges. Since polio hasn’t been seen in the country for decades, some health workers in the nation have never seen a case, so training is underway to teach them how to recognize symptoms. Also, a devastating tropical storm struck Malawi in January, according to STAT, washing away roads and bridges in some parts of the country and destroying refrigerators used to store vaccines in some areas.  

The response is being funded and coordinated with help from the Global Polio Eradication Initiative, which includes the WHO, UNICEF (the UN Children’s Fund), the service club Rotary International, the US Centers for Disease Control and Prevention, and the Bill and Melinda Gates Foundation.

Kayita says that work is underway to inform the public of the effort and ensure patient and parent cooperation. 

“We do have vaccine hesitancy. There are communities who are not easily accepting of vaccines,” Kayita tells STAT. “This is why a key pillar of the response is massive efforts around social mobilization.”