preparedness to polio virus importation
TRANSCRIPT
Preparedness to poliovirus importation
SIAs
routineHRAs
surveillance
Preparedness to wild poliovirus importation
Isolation of wild poliovirus in polio-free area is a public health emergencyImportation of wild poliovirus cannot be prevented until global polio eradication is achieved, but its spread within the country can be controlled
Pillars for preparedness High quality surveillance: key for early
detection High general population immunity:
achieved by routine and SIAsCountries should monitor population immunity (coverage, vaccination status of AFP cases). Special attention to high risk areas/populations
Key elements of a national plan Monitoring and early detection of
importation Response to importation
Rapid investigation of importation Enhancing surveillance for AFP and
wild poliovirus Immediate and appropriate
immunization response Documenting cessation of
transmission
Monitoring and early detection of importation
High quality AFP surveillance: Certification standard surveillance Appropriate geographic representation Monitoring sub-national level
Mobile and marginalized populations should be identified at borders and in other locations (cover with suitable immunization and surveillance activities)
Border areas: trained surveillance staff, cross- border notification
Hot case concept Timely reporting from the lab
Response to importation Rapid investigation:
Initial investigation & international expert risk assessment should be completed with WHO within 72 hours to establish emergency plan based on Case characteristics, area of transmission, surveillance quality, coverage……etc
Determining origin of virus (epidemiologic and genomic data)
Response to importation Enhanced surveillance:
Checking quality & active retrospective search to ensure it is not missed transmission
Determine extent of circulation and impact of control measures
Exclude re-establishment of virus circulation
Response to importation Enhanced surveillance:
Immediate notification of WHO, partners and neighbours
Immediate call on the identified expert group Informing surveillance staff and major health
facilities Enhancing active surveillance in all districts
around the case Contact sampling Monitoring reports at national/provincial levels Daily reports from critical areas Weekly review of situation by experts
Response to importation Immediate & appropriate immunization
response: Emergency meeting of national/international
experts, decide on response based on local situation within 72 hours
At least 3 large scale H-H rounds using type specific monovalent vaccine (4-6 weeks apart)
1st campaign within 4 weeks of confirmation Potential target: minimum 2 to 5 million <5
years (according to age of cases). In small populations entire country and bordering areas
Response to importation Immediate & appropriate immunization
response: Detailed guidelines in advance (mapping,
estimation of vaccine, teams, training modules, supervision, transport, Soc Mob, IM, Catch up, Cost)
Plan to be shared with WHO/UNICEF immediately to ensure resources (order & delivery of vaccine in 5 working days)
IM should determine level of coverage in HRA. <90% should be revaccinated
If border area involved, cross border coordination with neighbouring countries for SIAs through WHO
Response to importation Document Cessation of transmission
Enhanced surveillance for 12 months after last wild virus. (>2/100,000)
Detailed & comprehensive documentation to describe Detailed epi, clinical and virological data Data on surveillance analysis and quality Surveillance response Immunization response
Practical steps in developing a national plan
Setting Objectives Identification of importation risk
Possible sources HRAs and populations
Surveillance activities in border areas/high risk areas and populations
Measures to ensure high population immunity in these areas
Nomination of a group of experts
EpidemiologistVirologist
Paediatric neurologistCommunication/Soc. Mob
Senior MOH official
Practical steps in developing a national plan
Setting Objectives Identification of importation risk
Possible sources HRAs and populations
Surveillance activities in border areas/high risk areas and populations
Measures to ensure high population immunity in these areas
Nomination of a group of experts Protocol for response Required documentation
Regional Experience Several importations occurred
over years (cross border and distant) with very limiteed local circulation (Iran) or with no secondary cases (Saudi Arabia, Syria, Lebanon and Gaza)
International Spread of Poliovirus
23 countries with imported virus.
Country
Sudan
Yemen
Somalia
SaudiArabia
Oman
Index caseconf
Timely(33)
Delayed(55)
Delayed(58)
Timely(36)
Timely11&7 days
1st Immun.response
Timely 35Limited
tOPV
H-H-NID 40daysmOPV
NID-H-H14 daysmOPV
Preplanned17 000border
17 daysMop-upAug 21
Precedingactivities
NID45 days
after nset
NID-H-H14 daysmOPV
SNID7,8 Haj
9,11 border
NID 4-6 June6-8 July
Response
9 NIDs6 SNIDs
tOPV
8 NIDs2 SNIDs
Most mOPV
6 NIDsI SNIDmOPV
#duration
15513 mon
47912 mon
2119m+
RoundsAfter last
5 NIDs+SNID
2 SNIDs
Poliovirus Importation (RTAG) when a case is known to have been infected in
one country and then moves to another country, the case should be listed in the country where infection took place (genomic sequencing data would help in identifying the most probable source of infection).
The regional office should therefore revise the records with respect to the above mentioned case recorded currently under Saudi Arabia.
Polio-free countries which receive confirmed cases of wild poliovirus from other countries during the period of communicability should timely implement appropriate immunization and surveillance response.
LESSONS LEARNED1. Cessation of SIAs in situation of low routine → wide
immunity gap
2. Surveillance staff should expect polio as possibility among AFP cases
3. Delayed reaction to appearance of polio in neighbouring countries → loss of preventive effect
4. Immediate response before extensive spread is essential to ensure rapid cessation of circulation
LESSONS LEARNED(CONT’D)
5. Importance of studying population movement between and within countries and anticipate importation & spread
6. Avoid limited responses7. The main factor that prevents secondary
spread is high routine immunization8. Two well prepared and implemented
rounds using the appropriate monovalent vaccine are capable of knocking down the epidemic
LESSONS LEARNED(CONT’D)
9. In case of secondary spread we expect about 8-10 months programme of work
10. Having pockets of insufficiently immunized children due to refusals or inaccessibility, will be capable of maintaining some low grade transmission and few sporadic cases
11. Outbreaks can be explosive but are controllable12. Finishing the job efficiently is essential to avoid
conversion of the situation to endemicity13. Preparedness plans should be put in effect