Immunization, Vaccines and Biologicals
The Immunization, Vaccines and Biologicals department is responsible for targeting vaccine-preventable diseases, guiding immunization research and establishing immunization policy.
About

Poliomyelitis (Polio)

Polio can be prevented through immunization. Polio vaccine, given multiple times, almost always protects a child for life. The development of effective vaccines to prevent paralytic polio was one of the major medical breakthroughs of the 20th century. There are six different vaccines to stop polio transmission:

  • Inactivated polio vaccine (IPV) – protects against poliovirus types 1, 2, and 3
  • Trivalent oral polio vaccine (tOPV) – protects against poliovirus types 1, 2, and 3 - following the "OPV Switch" in April 2016, tOPV is no longer in use
  • Bivalent oral polio vaccine (bOPV) – protects against poliovirus types 1, and 3
  • Monovalent oral polio vaccines (mOPV1, mOPV2 and mOPV3) – protect against each individual type of poliovirus, respectively

If enough people in a community are immunized, the virus will be deprived of susceptible hosts and will die out. High levels of vaccination coverage must be maintained to stop transmission and prevent outbreaks occurring.

The Polio Eradication and Endgame Strategy

In May 2012, the World Health Assembly declared the completion of polio eradication a programmatic emergency for global public health and the Polio Eradication and Endgame Strategic Plan 2013-2018 was developed and, in November 2012, endorsed by SAGE. Under objective 2 of the Eradication and Endgame Plan, at least one dose of inactivated poliomyelitis vaccine (IPV) should be introduced into all routine immunization programmes globally, and trivalent oral polio vaccines (tOPV) will be replaced with bivalent (bOPV) in all OPV-using countries. The global "OPV Switch" was successfully conducted worldwide in April 2016 – setting the stage for the eventual withdrawal of all OPV.

In the new Eradication and Endgame strategy, research is a vital component of the Global Polio Eradication Initiative, providing the necessary evidence to guide the final steps to a lasting polio-free world and beyond. The Global Polio Eradication Initiative coordinates and supports an extensive program of research from a wide range of core scientific disciplines. The research program has two broad objectives:

  • to identify, develop and evaluate new tools and tailored approaches to maximize the impact of eradication efforts
  • to inform long-term policy for the post-eradication era.

See more at: Polio eradication research

Fractional dose IPV

This page presents the background information, programmatic considerations, implementation experiences and materials available related to the fractional dose administration of IPV. This is a resource for countries considering the introduction of fractional dose IPV in their routine programmes or in outbreak response.

Use of fractional dose IPV in routine immunization programmes: Considerations for decision-making

The evidence-base and information presented on this page is also summarized in the following document:

English | French

Background and evidence

As an alternative to the intramuscular injection of a full dose of IPV, countries may consider using fractional doses (1/5 of the full IPV dose) via the intradermal route. In the context of an IPV shortage, countries should consider instituting a 2-dose fractional dose schedule, where feasible, which could ensure that all eligible infants receive IPV, is dose-sparing and results in better immunogenicity than a single full dose of IPV. However, the programmatic and logistic implications of this option must be carefully assessed.

A schedule of fractional intradermal doses administered at 6 and 14 weeks ensures early and appropriately-timed protection. The 2 fractional doses should be separated by a minimum interval of 4 weeks. One fractional dose of IPV may be suitable for outbreak response if supplies are limited.

Key studies

Studies have demonstrated that a single fractional dose of IPV (1/5 of the full dose) gives lower seroconversion rates than a single full dose but after 2 fractional doses the rates are similar to those after 2 full doses.

Furthermore, 2 fractional doses of IPV, given intradermally at 6 and 14 weeks provide higher seroconversion rates than a single full dose (intramuscular) given at 14 weeks.

fIPV information package to support country decision-making

The following package presents a compilation of all the evidence related to fIPV, to support countries in considering implementing this strategy.

fIPV information package

 

Comparing IPV and fIPV

 

Country experience

fIPV Campaigns

Telangana state, India

In June 2016, India conducted a mass vaccination campaign using fIPV, reaching 311,064 children aged 6 weeks to 3 years (94% coverage) over a period of 6 days.

The success of this campaign indicates that, with appropriate preparation, an emergency response using fIPV can be implemented promptly and effectively. The following paper provides further background on the campaign planning, implementation, monitoring and evaluation.

fIPV in Routine Immunization

In April 2016, India introduced the use of fractional dose IPV into the routine immunization programme in eight states. In August 2016, the use of fIPV was expanded to an additional eight states and since March 2017 has been scaled up nationwide in all 36 states.

In July 2016, Sri Lanka changed to a schedule of 2 fractional doses of IPV in order to maximize the existing vaccine stocks in the country.

Bangladesh plans to introduce fractional IPV doses in 2017. Other countries in the South-East Asia Region are also considering a shift to the use of fractional IPV doses in their immunization schedule.

In March 2017, the Regional Technical Advisory Group (RTAG) for the Region of the Americas recommended that countries which administer >100 000 doses of IPV annually and have the capacity to adequately train and supervise health-care workers in intradermal injection, should move to a 2-dose fractional dose IPV schedule.