Severity: Warning Alert

Health: Increasing cases of polio reported in multiple provinces of Pakistan during 2020. Confirm vaccination; use basic health precautions.

This alert affects Pakistan

This alert began 23 Apr 2020 18:35 GMT and is scheduled to expire 23 Jun 2020 23:59 GMT.

  • Incident: Elevated poliovirus activity
  • Affected Area(s): Multiple provinces (map)
  • Period: January-April 2020
  • Cases: 81
  • Transmission: Food or water contaminated with fecal material

Summary
The number of poliovirus cases in Pakistan since the beginning of the year has risen to 81 cases. This is compared to a total of 15 cases reported over the same time period in 2019. Of these total cases, 41 were identified as wild poliovirus (WPV); the remaining 40 cases are circulating vaccine-derived poliovirus (cVDPV). Polio eradication efforts have been suspended due to the COVID-19 pandemic, indicating a likely increase in polio cases during 2020. Khyber Pakhtunkhwa remains the most affected area (55 cases) followed by Sindh (15 cases), Balochistan (7 cases), and Punjab (4 cases). This report represents the most recent information as of April 23.

Background and Analysis
Global polio eradication efforts has been suspended due to the COVID-19 pandemic. Despite an 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 towards the end of 2019 continuing into 2020.

What is especially worrying is the increase in the amount of circulating vaccine-derived poliovirus (cVDPV) cases. 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, 40 cases of cVDPV have been reported in 2020, compared to a total of 22 cases for the whole of 2019.

Similarly, wild poliovirus (WPV) has seen an increase to 41 cases this year compared to 15 cases in 2019 over the same time period. Since WPV remains endemic to the region, human reservoirs are likely to increase as a result of suspended vaccination campaigns. The risk of healthy individuals contracting polio from contaminated food or water remains negligible, but individuals with compromised immune systems or those suffering from long-term illness may be more susceptible.

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 travelling to Pakistan, 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.