International Events

Circulating Vaccine-Derived Polio Virus Type 2

(14 September 2022)

Announcing the Outbreak:
The World Health Organization announced detection of this outbreak in Britain and the United States of America from May to August 2022.
In Britain, the presence of poliovirus, for oral vaccination, was detected in environmental samples collected from London from 24 to 31 May and the samples confirmed the presence of the virus derived from the polio vaccine (VDPV2). On August 8 it was classified as circulating VDPV2 poliovirus.
Also, on August 8th, USA reported a non-vaccinated case of polio with no travel history for this case and after environmental sampling the presence of circulating VDPV2-derived poliovirus was detected.
Viruses discovered in Britain and America are genetically related to samples discovered in the occupied Palestinian territories as well.

About the Virus:
The vaccine-derived polio virus is genetically related and unmutated from the oral polio vaccine (OPV). In some cases, it multiplies in the intestine, and in very rare cases it may change genetically and spreads in poorly cleaned, overcrowded, and unvaccinated societies. A lower rate of vaccination in the community may lead to a longer survival of the circulating virus.
To ensure its presence in the community, two different samples must be taken from different places, separated by at least two months.

About the disease:
By its nature, the polio virus is highly contagious and almost exclusively affects children under the age of five and is transmitted through use of objects contaminated with human excreta or contaminated water and food and multiplies in the intestines to target the nervous system.

Initial Symptoms:
Incubation period of the disease is usually 7 to 10 days and can range from 4 to 35 days.
  • High temperature
  • Vomiting
  • Asthenia
  • Neck stiffness
  • Headache
  • Limb pain

Disease Control and Prevention:
World Health Organization recommended developing plans to assess and identify risks of the disease spreading around the world.
Whereas public health in Britain and America began with the following:
  • Intensifying health and environmental monitoring against circulating vaccine-derived poliovirus.
  • Child vaccination campaigns with the non-vital vaccine (IPV).
  • Ensure that children, immigrants, and refugees are vaccinated according to the vaccination schedule.
  • Circular to medical laboratories to immediately report any positive stool analysis.
  • Immediate reporting of acute flaccid polio cases.
*The thirty-second meeting of the International Health Regulations Emergency Committee on Polio, held in June 2022, agreed that the risk of international spread of poliovirus continued to constitute a Public Health Emergency of International Concern (PHEIC) and recommended that the period of recommendations be temporarily extended for three months.

Risk Assessment in the Kingdom:
The risk of VDPV2 emergence in the Kingdom is medium, while the risk of VDPV2 converting to cVDPV2 in the Kingdom is low.​​

Last Update : 09 October 2022 11:39 PM
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