RATIONALE FOR SURVEILLANCE
Targeted for eradication (9GPW 6.1). Highly sensitive surveillance for acute flaccid paralysis (AFP), including immediate case investigation; specimen collection is critical to detect wild poliovirus circulating in every infected geographical area with the ultimate objective of poliomyelitis eradication.
RECOMMENDED CASE DEFINITION
Clinical case definition
Any child under fifteen years of age with acute, flaccid paralysis* or any person with paralytic illness at any age when poliomyelitis is suspected.
*Including Guillain Barré syndrome
Suspected case: A case that meets the clinical case definition.
Confirmed case: See diagram in "Special Aspects".
RECOMMENDED TYPES OF SURVEILLANCE
Aggregated data of AFP cases to be included in routine monthly surveillance reports.
Zero reporting required at all levels.
AFP cases (possible poliomyelitis cases) must be reported immediately, be investigated within 48 hours (case-based data), and stool specimens must be collected within 14 days of paralysis onset.
All outbreaks should be investigated immediately. Active surveillance must be implemented in selected hospitals (also called "sentinel hospitals").
RECOMMENDED MINIMUM DATA ELEMENTS
• Number of third doses of oral poliomyelitis vaccine (OPV3) administered to infants
• Number of AFP cases
Case-based data (to be linked to specimen-based data for analysis)
• Unique identifier
• Geographical area (district and province) name
• Date of birth
• Date of onset of paralysis
• Date of notification
• Date of case investigation
• Total poliomyelitis vaccine doses received, 99 = unknownf
• Fever at onset of paralysis (1 = yes; 2 = no; 9 = unknown)
• Progression of paralysis within 4 days (1 = yes; 2 = no; 9 = unknown)
• Asymmetric paralysis (1 = yes; 2 = no; 3 = unknown)
• Date of 60-day follow-up examination
• Findings at 60-day follow-up (1 = residual weakness; 2 = no residual weakness; 3 = lost to follow-up; 4 = death before follow-up)
• Final classification (1 = confirmed; 2 = compatible; 3 = discarded; 4 = vaccine-associated)
Specimen-based data (to be linked to case-based data for analysis)
• Unique identifier
• Specimen number (1 = first; 2 = second; 3 = other; 9 = unknown)
• Date of paralysis onset
• Date of last OPV
• Date of stool specimen collection
• Date stool specimen sent to laboratory
• Date specimen received in laboratory
• Condition of stool (1 = good; 2 = poor; 9 = unknown)
• Date final culture results sent from laboratory to EPI
• Date intra-typic differentiation results sent from laboratory to EPI RESULTS
• Poliomyelitis type 1 isolated? (1 = yes, wild; 2 = yes, Sabin; 3 = yes, pending intratypic differentiation; 4 = yes, wild and Sabin mixed; 5 = no P1 isolate; 6 = specimen not processed)
• Poliomyelitis type 2 isolated?
• Poliomyelitis type 3 isolated? (1 = yes, wild; 2 = yes, Sabin; 3 = yes, pending intratypic differentiation; 4 = yes, wild and Sabin mixed; 5 = no P2 isolate; 6 = specimen not processed)
• Non-poliomyelitis enterovirus (NPEV) isolated? (1 = yes; 2 = none; 3 = specimen not processed)
RECOMMENDED DATA ANALYSES, PRESENTATION, REPORTS
• Cases by month, year, and geographic area
• OPV3 coverage by year and geographic area
• Completeness/timeliness of monthly reporting
Case-based data: same as aggregated data plus the following
• Confirmed cases by age group, immunization status, geographic area, month and year
• Confirmed cases from which wild poliovirus was isolated
• Cases with wild poliovirus by geographic area
• Compatible cases by geographic area
• All suspect cases by final classification
• Non-poliomyelitis enterovirus isolation rate
Performance indicators of surveillance quality
• % of all expected monthly reports that were received
• Annualized non-poliomyelitis AFP rate at least 1/100 000 children ≤15 years
• % of AFP cases investigated within 48 hours
• % of AFP cases with 2 stool specimens collected ≤14 days of onset and ≥24 hours apart
• % of specimens arriving at the laboratory in "good" condition
• % of specimens arriving at WHO-accredited laboratory within 3 days
• % of laboratory results sent within 28 days of specimen receipt
PRINCIPAL USES OF DATA FOR DECISION-MAKING
• Track wild poliovirus circulation
• Classify cases as confirmed, poliomyelitis compatible or discarded (see Special Aspects)
• Monitor routine coverage in all geographical areas and focus efforts in low performing geographical areas
• Identify high risk areas for planning mopping up immunization
• Monitor seasonality to determine low season of poliovirus transmission for NIDs planning
• Monitor performance of surveillance using standard indicators and focus efforts in low performing areas
• Provide evidence for polio-free certification
The scheme in the following illustration (Fig. 1) should be used to classify AFP cases. Countries should use the clinical classification until their surveillance performance meets the following three criteria:
1. A non-polio AFP rate of at least 1/100 000 children under 15 years of age.
2. Two adequate specimens* collected from at least 60% of detected AFP cases.
3. All specimens processed in a WHO-accredited laboratory.
Figure 1: WHO Classification System for Acute Flaccid Paralysis (AFP) Cases
*"Adequate specimens" means 2 specimens collected 24-48 hours apart and within 14 days of onset of paralysis. The specimen arriving at the laboratory must be of adequate volume (approximately 8-10 grams), have appropriate documentation (i.e. laboratory request form) and be in "good condition" (no leakage, no desiccation, and evidence (based on presence of ice or temperature indicator) that the reverse cold chain was maintained
**"Compatible cases" indicate surveillance failures and should be monitored for clustering in space and time.
See Regional Communicable Disease contacts on section "Communicable disease contacts in Regional Offices".
Headquarters: 20 Avenue Appia, CH-1211 Geneva 27, Switzerland
Vaccines and Other Biologicals (VAB)/Expanded Programme on Immunization (EPI)
E-mail: email@example.com / Surveillancekit@who.ch
Tel: (41 22) 791 4419/4363
Fax: (41 22). 791 4193 attn EPI