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Epidemiology of Vaccine Preventable diseases in Iran

Epidemiology of Vaccine Preventable diseases in Iran. Dr Seyed Mohsen Zahraei Center for Communicable Disease Control. Outline. The mean and importance of surveillance Surveillance system functionality Regional targets for Vaccine Preventable Diseases

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Epidemiology of Vaccine Preventable diseases in Iran

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  1. Epidemiology of Vaccine Preventable diseases in Iran Dr Seyed Mohsen Zahraei Center for Communicable Disease Control

  2. Outline • The mean and importance of surveillance • Surveillance system functionality • Regional targets for Vaccine Preventable Diseases • Progress towards achieving the targets in Polio, Measles and Rubella • Challenges and opportunities

  3. Definition of Surveillance Disease surveillance is the ongoing systematic collection, analysis and interpretation of data and dissemination of INFORMATION to those who need to know FOR ACTION to be taken

  4. Collection Analysis and Interpretation Action Dissemination Surveillance

  5. Importance of VPDs surveillance: • Demonstrate the real effectiveness of the vaccination programme in reaching its objective, reduction of VPDs: Measles control/elimination, MNTE, control of diphtheria and pertussis,….. • Demonstrate the need for intervention: introduction of new vaccines • Dangerous if not properly implemented: drawing incorrect conclusion: • decreasing trend/low estimate of a disease, the programme is doing fine • low burden of a disease, the new vaccine is not a priority

  6. Process & Stages of Surveillance • Notification of suspect case • Case investigation & specimen collection • Reporting • Laboratory testing • Integration of field and laboratory data • Final case classification • Feedback

  7. Core Surveillance Indicators • Timeliness of reporting • Reporting rate • Representativeness of reporting • Adequacy of epidemiological investigation • Timeliness of notification • Laboratory confirmation • Agent detection • Specimen transport & lab reporting

  8. Measles Surveillance in the Elimination Phase • Surveillance priorities: • Confirm all cases • Detect virus from all outbreaks (chains of transmission) • Surveillance system attributes: • Sensitive – identify all suspect cases of measles & rubella • Timely – prompt notification, investigation and response • Complete -- case investigations, laboratory confirmation & virus detection

  9. Surveillance Indicators (1) • Timeliness (& completeness) of reporting • Proportion of surveillance units reporting to the national level on time (Target: >80%) • Used to identify poorly functioning units / districts / governorates / countries

  10. Surveillance Indicators (2) • Reporting rate • Reporting rate of discarded non-measles non-rubella cases at the national level • Target: >2 cases per 100,000 population per year • Representativeness of reporting • Proportion of sub-national (province or governorate) units reporting >2 discarded cases/100,000 pop/yr • Combine units, if needed, to achieve >100,000 pop • Target: >80% • Used to assess surveillance sensitivity at national & sub-national levels

  11. Surveillance Indicators (3) • Adequacy of investigation • Proportion of all suspected measles & rubella cases with adequate investigation initiated within 48 hours after notification • An adequate investigation includes collection of all relevant data elements from each suspected case • Data elements: Identifiers, residence, place of infection, age, sex rash onset date, specimen collection date, etc. • Target: >80% • Used to assess timeliness & completeness of case investigation (epidemiological component)

  12. Surveillance Indicators (4) • Laboratory confirmation • Proportion of suspected cases with adequate specimen for detecting acute measles or rubella infection collected and tested by a proficient laboratory. • Adequate specimens include serum sample, DBS, or oral fluid, taken within 28 days after rash onset • Cases not tested but confirmed by epi-linkage to a confirmed case of measles, rubella or other communicable disease excluded from denominator • Target: >80% • Used to assess completeness of case investigation (“serological” component)

  13. Surveillance Indicators (5) • Virus detection • Proportion of laboratory-confirmed outbreaks (chains of transmission) with adequate specimens for detecting measles or rubella virus collected and tested in an accredited laboratory. • Adequate specimens include a) throat swabs or urine samples for virus isolation (collected <5 days after rash onset), or b) throat swabs or oral fluid samples for molecular detection (collected <14 days or <21 days, respectively, after rash onset) • Target: >80% • Used to assess completeness of case investigation (virological component)

  14. Surveillance Indicators (6) • Timeliness of specimen transport • Proportion of specimens received at the laboratory <5 days [Target: >80%] • Timeliness of laboratory reporting • Proportion of results reported by the laboratory <4 days of specimen receipt [Target: >80%] • Used to assess timeliness of case investigation (epidemiological & laboratory components)

  15. Summary • Standardized definitions have been developed for case classification & elimination verification • In the elimination phase, surveillance for measles & rubella needs to be • Geographically representative • Sensitive • Timely • Complete • Current indicators are used to assess quality of case investigations & overall surveillance system • Targets for indicators (>80%) are minimums

  16. Soonest possible (for countries that haven’t achieved yet) Achieve at least 90% DPT3 coverage at national level AND 80% in every district (target date 2010) Eliminate MNT soonest possible (target date 2007) By 2012 Eradicate polio By 2015, Eliminate measles (regional target) Reduce HBsAg prevalence to < 1% among <5 years children (Regional target) Reduce VPDs morbidity and mortality by 2/3 compared to 2000 (GIVS goal) Introduce new vaccines (Hib, PCV and Rota) to all countries as soon as possible (RC58, 2011) The Targets: for each country

  17. Poliomyelitis Eradication InitiativeThe End Game

  18. Poliomyelitis was selected for eradication because : • There is no animal reservoir. • There is no chronic carrier state. • Poliovirus survives poorly in the environment. • Presence of effective vaccine against the disease

  19. The Global Polio Eradication Emergency Action Plan aims to boost vaccination coverage in Nigeria, Pakistan and Afghanistan, the three remaining polio endemic countries, to levels needed to stop polio transmission.

  20. Polio-free Status of 21 Countries of EMRO is Maintained - cVDPV in Yemen 2011 last case Oct 2011 - Continuous cVDPV in Somalia from 2008- 2012 with last case in 23/07/2012 EMRO 09/09/2012

  21. % of NP AFP cases 6-< 59 months with 3 or more OPV doses by province in EMR countries, 2012 Routine OPV3 coverage, 2011 Source: WHO/UNICEF Estimates of National Immunization Coverage EMRO 09/09/2012

  22. Immunity profile of NP AFP cases 6-59 months in EMR countries, 2012 up to 09/09/12

  23. VDPVs isolated in EMR

  24. Measles and Rubella Elimination in EMR Countries

  25. Reported cases of measles 2000-2011 Measles cases down by 62% Measles deaths down by 74% Progress in global measles control, 2000–2010. WER 3 Feb 2012, vol. 87, 5 (pp 45–52) Lancet in press; 2012 IVB model by Simons, Ferrari et al.

  26. 2,052 Source: Country reports Inadequate surveillance

  27. Measles Cases, Incidence and Virus Genotypes, 2009-2012* * Up to August

  28. Measles Confirmed Cases, 2009 – 2012* cases * Display in line graph the distribution of confirmed measles cases by month for 2009 – 2012 up to August

  29. Geographical Distribution Of Confirmed Measles Cases By Province, 2009 - 2012 • Map 2009 • Map 2011 • Map 2012 • Map 2010

  30. Confirmed measles Cases ( Lab+Epi-linked ) by age group 2009 - 2012

  31. Source: Country reports Inadequate/No surveillance

  32. Rubella detected cases based on fever and rash surveillance system, Iran, 2005-2011

  33. CRS Surveillance in Iran • Established in 2004, after MR mass campaign. • Accelerated passive surveillance, comprehensive • All hospitals which may admit suspected cases are covered

  34. CRS suspected Case Definition • An infant (0-11 months) whose mother had suspected or confirmed history of rubella in pregnancy • An infant (0-11 months) with heart disease and or ophthalmic disease and or deafness

  35. CRS suspected cases by sign

  36. Summary • Progress • Well developed PHC network • High immunity level • Robust surveillance system • Challenges • New reporting sites • Training • Private sector partnership • Need to performance indicators

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