Pathogen

• Poliovirus, picornaviridae

• Vaccine-derived poliovirus (VDPV): The live attenuated poliovirus strains in OPV can circulate in a community for an extended period of time and cause cases of paralytic poliomyelitis, known as circulating vaccine-derived poliovirus (cVDPV), and accumulate further mutations.

Epidemiology & transmission

• Oral transmission, humans are the only natural hosts and reservoir

Clinical

• Selectively infects and destroys anterior horn cells in the spinal cord, resulting in 'acute flaccid paralysis' (although 99% of infected people show no paralytic manifestations)

• Wild poliovirus cans have decreased by >99% since 1988 (350,000 cases to 22 in 2017)

• Endemic transmission in Afganistan, Nigeria, Pakistan

Vaccination

Oral polio vaccine () SALK

• vaccine-associated : vaccinated individual and close contacts

• vaccine-derived poliovirus (VDPV)

• bivalent and multivalent OPV (bOPV, mOPV2, and ... tOPV again)

Inactivated poliovirus vaccine (IPV)

• low- and middle-risk countries. Qualified for routine immunisation. Global introduction of IPV from 2016 (at least one dose). Multivalent inactivated vaccines available SABIN

Control

Basic strategies of polio eradication

• Extensive immunisation with OPV (IPV)

• Acute flaccid paralysis (AFP) surveillance

• Lab diagnosis

Issues

Vaccine associated....

References

Stop Polio