12-Jan-2017: South East Asian countries opts for fractional doses of IPV after India.

Due to global shortage of injectable inactivated polio vaccine (IPV) polio vaccine, countries in the South East Asian region have now opted for fractional doses of IPV, first adopted by India, to tackle these "challenging conditions", the World Health Organization (WHO).

On the 6th anniversary of the last case of wild polio virus in the region, WHO Regional Director for South-East Asia Poonam Khetrapal Singh said that by introducing fractional doses of IPV, nations are not only saving vaccine cost but also not compromising on the protection that it provides to the children against polio.

"On the sixth anniversary of the last case of wild polio virus in the SEAR (South East Asian Region), WHO commends countries in the Region for their continued efforts to protect children against this crippling virus and maintain the region's polio-free status, despite challenging conditions.

WHO said that India became the first country globally to introduce fractional doses of IPV in childhood immunisation programme in eight states and Union territories in early 2016.

While this initiative is now being scaled up nationwide, Sri Lanka has also followed suit in July 2016 while Bangladesh has decided to introduce fractional IPV doses this year.

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.

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.

Since polio-free certification on March 27, 2014, all countries in WHO South East Asia Region have been working towards timely implementation of the global polio endgame strategy to achieve a polio-free world.

South East Asia was the first WHO Region to complete the polio vaccine switch from the traditionally used trivalent oral polio vaccine (tOPV) to the bivalent vaccine (bOPV) to prevent any paralysis caused by type 2 polio virus strain in tOPV.

"As a part of the global polio endgame strategy, countries in the Region have introduced IPV to supplement the oral polio vaccine (OPV), and ensure protection against all types of polio viruses, while the programme globally strives towards stopping polio virus transmission and cessation of OPV use," Singh said.

Since January 13, 2011, the last time that wild polio virus crippled a child in WHO South-East Asia Region, should be a reminder to all countries of the continued need to reach every child with polio vaccines and to strengthen disease surveillance so that polio virus does not return to cripple children in our Region.

WHO's SEAR comprises Bangladesh, Bhutan, Democratic People's Republic of Korea, India, Indonesia, Maldives, Myanmar, Nepal, Sri Lanka, Thailand and Timor-Leste.