Afghanistan: Elevated polio activity continues nationwide during 2020

Event

Authorities report elevated poliovirus activity in Afghanistan, with three additional wild poliovirus (WPV) and 24 additional circulating vaccine-derived poliovirus (cVDPV) cases reported between November 12-24, bringing the total to 216 cases since beginning 2020. This total compares to 21 cases reported nationwide during a similar period in 2019. Of these total cases, 56 were identified as WPV; the remaining 160 cases are cVDPV. Cases have been reported in multiple locations across the country, mostly in the south and eastern provinces, with Takhar recently reporting its first case. This report represents the most complete data available as of December 2.

Context

Global polio eradication efforts have resumed after a four-month suspension due to the coronavirus disease (COVID-19) pandemic. Despite a significant improvement in the number of poliovirus cases over the past decade due to nationwide vaccination campaigns, this virus remains endemic to the Pakistan and Afghanistan regions. A surge in the number of cases was observed toward the end of 2019, continuing into 2020.

The increase in the amount of cVDPV cases remains a concern. Cases of cVDPV 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 infecting susceptible individuals. To date, 160 cases of cVDPV have been reported in 2020, compared to no cases for the whole of 2019.

Polio is highly infectious and can spread rapidly through contact with infected fecal material, such as in contaminated food and water. Infections are generally mild, but one in 200 cases leads to irreversible paralysis. Among those victims, 5-10 percent die when respiratory muscles become affected. The risk of paralysis increases with age. There is no specific treatment for polio.

Advice

Visit a doctor to receive a precautionary polio booster before traveling to Afghanistan, 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.