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

Epidemiology of Vaccine Preventable diseases in Iran

Dr Seyed Mohsen ZahraeiCenter for Communicable Disease Control

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

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

Surveillance

• 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

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

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

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

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

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

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)

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)

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)

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)

SummarySummary

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

The Targets: for each country

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 polioBy 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)

Poliomyelitis Eradication InitiativeThe End Game

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

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.

Polio-free Status of 21 Countries of EMRO is Maintained

EMRO 09/09/2012

Polio Cases2011September 2012

CountryP1P3P1P3P1P3

Pakistan19623221

Afghanistan8001700

- cVDPV in Yemen 2011 last case Oct 2011

-Continuous cVDPV in Somalia from 2008- 2012 with last case in

23/07/2012

%of NP AFP cases 6-< 59

months with 3 or more OPV

doses by province in EMR countries,

2012

Source: WHO/UNICEF Estimates of National Immunization Coverage

EMRO 09/09/2012

Routine OPV3 coverage, 2011

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

Country20052006200720082009201020112012

AFGcVDPV2 (01)cVDPV2 (05)cVDPV 2 (01)

EGYaVDPV2 (Sewage Behira)

iVDPV3 (01)

aVDPV2 (Sewage Behira)

aVDPV 2 (Sewage Behira)

aVDPV 1 Helwan-Cairo

iVDPV1 (01)

iVDPV2 (01)

iVDPV3 (01)

iVDPV2 (01)

IRANiVDPV2 (01)iVDPV2 (01)

iVDPV3 (01)

iVDPV1 + iVDPV2 (01)

iVDPV2 (01)iVDPV2 (02)iVDPV2 (01)

KWTiVDPV3 (01)

IRAQiVDPV2 (01)

MORiVDPV2

Detected in Spain

SAAiVDPV2

SOMVDPV2 (02)cVDPV2 (03)cVDPV2 (07)cVDPV 2 (02)cVDPV2 (09)cVDPV2 (01)

SYRVDPV2 (01)VDPV2 (01)aVDPV 2(01)

SudanaVDPV2 (01)

South Sudan

aVDPV2 (01)aVDPV2 (01)

TUNiVDPV2 (1)iVDPV1 (a)P1 iVDPV (a)

P3 iVDPV? (b)

YEMiVDPV2cVDPV 2 (09)aVDPV2 (01)

aVDPV3 (01)

VDPVs isolated in EMR

Measles and Rubella Elimination in EMR Countries

Measles deaths down by 74%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.

Measles cases down by 62%

Measles cases down by 62%

0100,000200,000300,000400,000500,000600,000700,000800,000900,000

2000 2002 2004 2006 2008 2010

AFR AMR EMR EUR SEAR WPR

Reported cases of measles 2000-2011

Source: Country reports Inadequate surveillance

2,052

Measles Cases, Incidence and Virus Genotypes, 2009- 2012*

YearMeasles Suspected Cases

Confirmed Measles casesMeasles Incidence/Million

Detected Genotype LabEpi-

LinkedClinical/ Compatible

Total

2009128211871322573.4D4 , H1

2010248925902755347.15D4 , D1

201126411801141351.8D4

201223941544492012.6B3, H1, D4

* *Up to August

Measles Confirmed Cases, 2009 – 2012*ca

ses

*Display in line graph the distribution of confirmed measles cases by month for 2009 – 2012 up to August

Map 2011

Geographical Distribution Of Confirmed Measles Cases By Province, 2009 - 2012

Map 2009Map 2009

• Map 2012

• Map 2010

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

Source: Country reports Inadequate/No surveillance

 Suspected

casesNumber of

TestedRubella Positive

Measlespositive

2005 536410116

2006 9437711545

2007 900796521

2008 9728681015

2009 128211599118

2010 2489221222258

2011 247622321518

Total9598844887460

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

CRS Surveillance in Iran

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

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

CRS suspected cases by sign

Summary• Progress

– Well developed PHC network– High immunity level– Robust surveillance system

• Challenges– New reporting sites– Training – Private sector partnership– Need to performance indicators