Travel Alerts

Wild Poliovirus Eradication Can Be Achieved

Sabin strain based Inactivated Polio Vaccine (sIPV) demonstrated an immunogenicity profile non-inferior to that of the conventional IPV
children running, laughing
Cameroon (Vax Before Travel)

Polio eradication was in the spotlight as the World Health Organization (WHO) gathered at the 72nd World Health Assembly in Switzerland. 

In his opening address to the delegates, WHO Director-General and Chair of the Polio Oversight Board, Dr. Tedros Adhanom Ghebreyesus talked about the long-winding journey of polio eradication, on May 24, 2019. 

“We have launched a new strategy to address the most difficult remaining areas in Afghanistan and Pakistan. I have no doubt we will succeed in making polio history,” said Dr. Adhanom. 

WHO Member States expressed overwhelming support of the Polio Endgame Strategy 2019-2023.  

The new strategy sets the stage for a decisive win against polio through the parallel pursuit of the wild poliovirus and circulating vaccine-derived poliovirus. 

The Strategic Plan incorporates collaboration with other health interventions, fostering stronger alliances and managerial innovations by working in close coordination with governments in endemic countries. 

This Plan is needed since the number of new polio cases reported in 2019 will soon exceed 2018 totals. 

As of May 29, 2019, the following countries reported polio cases:

  • Pakistan – 2 wild poliovirus type 1 (WPV1) cases and six WPV1-positive environmental samples, for a total of 19 cases
  • Afghanistan – 1 WPV1-positive environmental sample, for a total of 7 cases
  • Nigeria – 2 circulating vaccine-derived poliovirus type 2 (cVDPV2)-positive environmental samples, for a total of 8 cases
  • Somalia – 1 cVDPV2 case
  • Cameroon – 1 cVDPV2-positive environmental sample
  • Iran – 1 WPV1-positive environmental sample

Furthermore, there is good news regarding polio vaccines.

The Oral Polio Vaccine (OPV) has been the predominant vaccine used to eradicate the polio virus. Virtually all WHO Member States which have eradicated polio used OPV to interrupt person-to-person transmission of the virus. 

But newer polio vaccines are now available in most countries. 

Following the introduction of inactivated polio vaccine (IPV) into Zimbabwe and Mongolia’s routine immunization programs, every WHO Member State has now introduced the children’s protective vaccine. 

The IPV consists of inactivated (killed) poliovirus strains of all 3 poliovirus types. It produces antibodies in the blood to all types of poliovirus. 

In the event of infection, these antibodies prevent the spread of the virus to the central nervous system and protect against paralysis. 

“Introducing IPV into routine immunization programs is a critical milestone on our journey towards a polio-free world,” said Dr. Tedros Adhanom Ghebreyesus, Director-General of the World Health Organization and Chair of the GPEI Polio Oversight Board, in a press release. 

Additionally, a new study found that the novel OPV2 candidates were safe and immunogenic in IPV-immunised adults. 

And, this study published in January 2019, reported the data to support the further development of these vaccines to potentially be used for maintaining global eradication of neurovirulent type-2 polioviruses. 

This study found the Sabin strain–based Inactivated Polio Vaccine (sIPV) demonstrated an immunogenicity profile non-inferior to that of the conventional IPV, and it displayed a good safety profile.

This phase 3 clinical trial found seroconversion rates in the sIPV and IPV groups were 98% and 94.1%, respectively, for type 1 poliovirus; and 98.9% and 97.7%, respectively, for type 3.   

Polio has been eliminated from the USA thanks to widespread polio vaccinations, says the Centers for Disease Control and Prevention (CDC).

Since 1979, no cases of polio have originated in the United States. 

This success can be traced to vaccination programs which enable children to get 4 doses of polio vaccine.

For additional information on countries with polio circulation and vaccine recommendations, consult the travel notices on the CDC Travelers’ Health website.

Pre-trip, polio vaccine counseling appointments can be scheduled at Vax-Before-Travel.

Article by
Dani Reiter