Factsheet: Facts about new Polio outbreak in Zimbabwe

Nearly 20 years after the World Health Organisation (WHO) declared Zimbabwe free of Polio, the southern African country has discovered a new rare strain of the deadly disease in the capital Harare.

Where was the new virus detected?

The Ministry of Health and Child Care (MoHCC) confirmed the detection of a vaccine derived poliovirus type 2 (cVDPV2) in the sewer system of Harare suburbs, including Budiriro, Mbare and Mufakose.

The virus was later detected in a 10-year-old in Sanyati, 200 km from Harare, which prompted the ministry to inform the WHO and to activate a “Polio Incident Management System” in preparation for a nationwide vaccination campaign to stop the rapid transmission of the disease, which the international health co-ordination body had recorded as eliminated in 2005.

What is vaccine-derived poliovirus type 2 (cVDPV2)?

According to the World Health Organisation (WHO), (cVDPV2) is a well-documented strain of the poliovirus mutated from the strain originally contained in the Oral Polio Vaccine (OPV).

The vaccine (OPV) contains a live, weakened form of poliovirus that replicates in the intestine for a limited period, thereby developing immunity by building up antibodies. The current strain of the virus was detected in Harare through Environmental Surveillance on 20 October 2023.

How does the Vaccine Derived Polio Virus spread?

The incubation period is usually 7-10 days but can range from 4-35 days. Up to 90 percent of those infected are either asymptomatic or experience mild symptoms and the disease usually goes unrecognized.

The virus is transmitted from person-to-person, mainly through ingesting contaminated water or food.
OPV strains genetically change and may spread in communities that are not fully vaccinated against polio, especially in areas where there is poor hygiene, poor sanitation, or overcrowding.
The lower the population’s immunity, the longer this virus survives and the more genetic changes it undergoes.

How to stop the vaccine-derived poliovirus type 2?

The best way to prevent or stop the outbreak of the vaccine-derived poliovirus type 2 is to vaccinate children as they are the most at risk population.

What is the Ministry of Health and Child Care doing to stop the transmission?

The health ministry will work closely with the Ministry of Primary and Secondary Education in its plan to roll out two rounds of emergency national polio vaccination targeting all children below 10 years of age to boost their protection from the virus.

The first round is scheduled between 20 February and 1 March 2024 while the second round is scheduled between 19 and 29 March 2024 for all provinces.

The emergency vaccination campaign which will be conducted in close collaboration with the Ministry of Primary and Secondary Education targets to vaccinate and protect a total of 4 206 013 children in each of the two rounds.

Where will the vaccine be administered?

Vaccination will be done through deployment of house-to-house and mobile vaccination teams in addition to vaccination at all health facilities during the campaign days.