Expanded programme on immunization

WPR countries conduct subnational risk assessments and SIAs

Children in Cambodia showing through their finger marks that they were vaccinated against polio and measles

As part of the efforts to stay polio-free, Member States in the WHO Western Pacific Region have begun to conduct sub-national risk assessments to weigh up the extent to which an imported wild poliovirus could spread and cause a polio outbreak. Subsequently, countries are implementing risk mitigation activities and aiming at increasing their population immunity, the best defence against imported poliovirus.

In Cambodia a supplementary immunization activity (SIA) focusing on measles was conducted from February to April 2011 targeting children 9 to 59 months of age. One dose of oral poliovirus vaccine (OPV) was provided to 345,015 children ages 0 to 59 months of age living in high risk communities. The 2nd round of measles SIA was conducted from 1 to 30 November. The SIA aimed this time at high risk villages previously identified by a national EPI Review in 2010, and by the results of the 1st round in February 2011. OPV was again provided to 249,914 children aged 0 to 59 months, and in both rounds Vitamin A and Mebendazole were also given. This approach focusing on high risk areas will not only make a significant contribution to measles elimination by 2012 but also to keeping the country polio-free.

Baby in Lao PDR is receiving supplementary immunization against polio

In a similar approach to maximise opportunities, the Lao People’s Democratic Republic used a national measles-rubella (MR) SIA conducted in November and December 2011 to also provide OPV to all children from birth to 59 months of age. Initial plans had been to conduct only MR SIA together with the Child Health Days (which traditionally give vitamin A and Mebendazol) but the current situation in the Region with the wild poliovirus importation and subsequent polio outbreak in China made the Government of the Lao PDR recognize the risk and add OPV to the measles immunization campaign. Over 88% of the target age group have been vaccinated with OPV; that is 716,478 children. As some mop-up activities are still going on, the final coverage is expected to exceed 90%.

Prof. Nguyen Tran Hien (Director, National Institute of Hygiene and Epidemiology, Viet Nam), providing OPV in Ha Giang during supplementary immunization campaign against polio

Viet Nam had identified in its subnational risk assessment exercise that 1,080 communes in 77 high risk districts in 23 provinces would required supplementary immunization. A total of 777,746 children from birth to 4 years old were targeted to receive two extra doses of OPV in two rounds of SIAs conducted from September to November 2011. This represents approximately 10% of all children under 5 years old.