DRC: Polio transmission continues across multiple locations through March 14 /update 3

Event

Health officials have reported 129 additional cases of circulating vaccine-derived poliovirus (cVDPV) in the DRC Dec. 8, 2022-March 14, 2023, bringing the total case count to more than 430 cVDPV cases since Jan. 1, 2022; this consists of 115 cVDPV1 and 318 cVDPV2 cases. This caseload is compared to 28 cases reported over a similar period in 2022. Most cases have been reported in Haut Lomami and Tanganyika provinces, with disease activity also reported in Bas Uele, Haut Katanga, Lualaba, Maniema, North Kivu, South Kivu, and Tshopo. This represents the most complete data available as of March 20.

Context

The DRC reported 28 cases of cVDPV in 2021, 81 cases in 2020, 88 in 2019, and 20 in 2018.

cVDPV cases are a rare result of widespread vaccination using oral polio vaccine (OPV), which contains a live but weakened strain of poliovirus. When a child is immunized with OPV, the weakened vaccine-virus replicates in the intestine for a limited time, leading to the development of antibodies. In areas of inadequate sanitation, vaccine-virus excreted by these children can spread in the community. Many areas of the DRC have chronically low vaccination rates. Under such conditions, individuals vaccinated using oral polio vaccines can sometimes transmit cVDPV to other vulnerable individuals.

Polio can spread through contact with infected fecal material, sometimes found in contaminated food and water. Poliovirus infections are generally mild, but one in 200 cases leads to irreversible paralysis. Among those victims, 5-10 percent die when respiratory muscles become involved. The risk of paralysis increases with age. There is no specific treatment for polio, but vaccination can prevent infection.

Advice

Visit a doctor to receive a precautionary polio booster before traveling to areas recently affected by poliovirus activity, as even mildly symptomatic or asymptomatic people are infectious. Practice basic food and water precautions: drink only boiled, bottled, or purified water, and ensure that food is properly prepared and served hot.