Targeted supplementary immunization NIDs and Mop-ups in the Western Pacific Region

What is targeting? targeting is defined as placing particular emphasis on the planning, preparation, and conduct of immunization for particular areas or groups at high risk of ongoing transmission of wild poliovirus

Why target? wild poliovirus circulation is not uniform the quality of supplementary immunization (NIDs and SNIDs) is not consistently high some areas or groups may have low coverage or be entirely missed if unimmunized children are not evenly distributed wild poliovirus may still be able to circulate in pockets of low coverage

Difference between targeting (mop-up) and usual NID or SNID FOCAL - confined to known high risk areas INTENSE more resources per head more staff and supervisors house to house, boat to boat LONGER DURATION - need more than one day SUPERVISION CRITICAL 2

When it is possible to target not appropriate in early eradication phase: wild virus circulation widespread surveillance weak inadequate experience in NIDs/SNIDs appropriate in later eradication phase: wild virus circulation reduced to pockets surveillance good enough to identify high risk areas/groups good experience and confidence with NIDs

How can targeting be done can be done as part of larger supplementary immunization activities (NIDs and SNIDs) can be done as a separate activity focussing only on the designated high risk area/group, (separate mop-up) provided that the planning and preparation is adequate, either option can achieve better coverage of high risk groups

Targeting in WPR targeting in NIDs/SNIDs in Cambodia, China, Laos, Philippines, and Viet Nam most extensive in Cambodia and Viet Nam (Mekong Delta) during NIDs in 1995/96 (Viet Nam), 1996/97 & 1997/98 (both countries) separate mop-ups conducted in Cambodia and Viet Nam 1997 and 1998

Criteria for selecting high risk districts (targeting, mop-ups) WPR wild poliovirus circulation in previous 12-24 months (mapping!) clusters of clinically confirmed polio, or high risk (compatible) AFP cases (mapping!) districts bordering polio endemic areas districts along Mekong river/ major waterways districts with poor surveillance performance low routine or NID coverage

High Risk Factors for AFP Cases Zero dose (< 3 doses) OPV and/or Fever at onset and/or Wild poliovirus in the same or border district within the last 12 months, and/or Residual paralysis at 60 days in cases in a cluster 3

1994 1995 1996 1997 74 cases 31 cases Imported cases Indigenous cases @ ! Indigenous cases 1996 21 cases 1997 9 cases

Operation of mop-ups 1 Target population: Teams used (Cambodia): > 1 million Cambodia (over 50% of the total) 1 million Viet Nam (25% of southern region) 50,000 Laos (20% of southern provinces) Teams used (Cambodia): 7490 fixed posts (3 staff) 2200 mobile teams (2 staff) total roughly 1 team per 120 target children!

Operation of mop-ups 2 several days (12) for each round mixture of strategies; fixed posts with outreach, mobile teams on foot, bike, boat medical/nursing students excellent good preparation carried out; photographs, walk over the ground plenty of supervisors with vaccine

Fixed and mobile teams, NIDs and mop-up, Cambodia

Children per team, NIDs and mop-up

Results of targeting: Viet Nam % of zero dose children found by mobile teams

Results of targeting: Cambodia % of zero dose children found by mobile teams

Cost of campaigns per immunized person

Active search for AFP during mop-up carried out in Cambodia, Viet Nam can add some information on high risk areas and areas where surveillance data is poor best restricted to high risk areas to ensure quality of information no substitute for good AFP surveillance

Lessons 1: Surveillance data surveillance data critical in identifying high risk areas quality of data important (AFP rate, specimen collection rate) regular analysis of data: at minimum each month mapping, mapping, mapping

Lessons 2. Immunization strategies new strategies alone will not assure high coverage! fixed immunization posts alone not enough, multiple strategies necessary flexible use of mobile teams depending on area: urban houses, boats, main roads supervisors essential (should be highly mobile)

Guidelines for Future HRRI