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

2. 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

3. 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

4. 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

5. 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

7. 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

8. 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

9. Criteria for selecting high risk districts (targeting, mop-ups) WPR
wild poliovirus circulation in previous 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

10. 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

11. 1994 1995 1996 1997 74 cases 31 cases Imported cases Indigenous cases@ !
Indigenous cases
1996
21 cases
1997
9 cases

16. 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!

17. 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

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

19. Children per team, NIDs and mop-up

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

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

22. Cost of campaigns per immunized person

23. 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

24. 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

25. 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)

27. Guidelines for Future HRRI