Measles surveillance sepio mtg 18 20 may 2011 (ab) v1

Measles: Disease, epidemiology and surveillance: Data for Action

Dr A S Bose, WHOWorkshop on Immunization Programme, GoI

Hotel Royal Plaza, New Delhi 19 May 2011

SEPIO Meet, 18-20 May 2011 Bose, WHO

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Overview

• Measles virus, disease, and transmission

• Measles vaccine

• Control strategies and evidence of impact

• India surveillance data

• Linking surveillance data to control activities


3Source: Global measles elimination. Moss WJ & Griffn DE. Nature Dec 2006, Vol 4: 900-908


4Source: Global measles elimination. Moss WJ & Griffn DE. Nature Dec 2006, Vol 4: 900-908


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Clinical course of measles

Incubation period( 7–18 days before rash)

18 days before rash

Exposure happened the earliest 18 days before rash

4 days before rash

Is the probable start of infectiousness

Prodrome(about 4 days)

-18 -17 -16 -15 -14 -13 -12 -11 -10 -9 -8 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 8

4 days after rash

Is the probable end of infectiousness

Rash(about 4–8 days)

RASH

The case can be identified

here


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Measles disease

• One of the most infectious agents known

• Classic manifestations:

– Fever / Maculopapular rash / The 3C: Cough, Coryza (runny nose), Conjunctivitis (red eyes)

• Humans are the only reservoir

• Multiplies in the respiratory tract

• Airborne transmission via respiratory secretions or aerosols

• Complications: mostly in 2nd and 3rd weeks

• Case Fatality Ratio (CFR): – 0.1 – 10 % (highest in

children <2 yrs)

– May reach up to 30% in humanitarian emergencies

• Lack of timely medical care for complications and malnutrition leads to high CFR


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Measles complicationsCorneal scarring causing blindnessVitamin A deficiency

(Common)Encephalitis

Older children, adults

≈ 0.1% of cases

Chronic disability

Pneumonia &Diarrhea (Common)

Diarrhea common in developing countries

Pneumonia ~ 5-10% of cases, usually bacterial

desquamation


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Measles vaccine

• Composition: live virus - freeze dried powder (no preservative)

• Requires reconstitution (diluent from manufacturer)

• Efficacy depends on age

– At 9 months of age 85%

– At 12 months of age 95%

• Vaccine provides long-lasting immunity (likely lifelong)


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Coverage and immunity• Vaccination coverage does not equal population

immunity!

• 95% population immunity not achievable with only 1 dose (routine) even at very high vaccination coverage

• Accumulation of susceptible persons occurs over time

• High risk of outbreak when number of susceptibles in <5 population (primary vaccine failure + all unvaccinated) ≥ birth cohort

Second opportunity for vaccination against measles needed to achieve & sustain high population

immunity


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Overview


• Measles vaccine





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Measles control strategies

1st dose coverage

2nd dose coverage

(routine delivery or SIAs)

Surveillance

Case Management

Mortality Reduction

>90%*

>90%*

Aggregate or case-based

Vitamin A Supportive Rx

Elimination

>95%

>95%

Case-based

Vitamin A Supportive Rx

*GIVS target > 90% nationally, > 80% in every district

Evidence of impact: Bangladesh

When strategies are

properly implemented


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Measles vaccination valid coverage by 12 months of age, 2005 and 2010

Source: CES 2005 and 2010

2005 2010

81% (52/64) districts achieved ≥80% coverage in 2010

2005 2010

<70% 27 1

70-79% 23 11

≥80% 14 52

LegendCoverage

MCV1Number of Districts


14

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Cases from lab confirmed MEASLES outbreaks

Cases from lab confirmed RUBELLA outbreaks

Cases from lab confirmed MIXED outbreaks

Measles Catch-upCampaign (9m- 10 yrs)

`

National Measles Catch-up Campaign

(9m- 5 yrs)

Impact of Measles Immunization Campaigns: Marked Reduction of Cases from Lab Confirmed Outbreaks

Bangladesh, 2004-2010 (May)A

ccel

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easl

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illan

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Source: Monthly case-based data up to May 2010

Lack of impact and resurgence of disease: WHO African Region

When strategies are not implemented properly or not in

a sustained manner


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No. of reported measles cases and coverage with 1st dose of measles containing vaccine (MCV1) in infants

WHO African Region 2000-2010*

*Source: Measles outbreaks and progress towards meeting measles pre-elimination goals: WHO African Region 2009-2010. [Editorial note] Weekly Epidemiological Record. No. 14 1st April 2011


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Measles outbreak in WHO African region 2009-2010: Reasons*

• “…Suboptimal coverage of routine immunization and SIAs led to accumulation of susceptible individuals…”

• “…Outbreak cases occurring among older children and young adults suggest long standing gaps in vaccination activities– Reports of SIA administrative coverage >100%

suggest that reported coverage figures may have been inaccurate and inflated …”

•

*Source: Measles outbreaks and progress towards meeting measles pre-elimination goals: WHO African Region 2009-2010. [Editorial note] Weekly Epidemiological Record. No. 14 1st April 2011


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Overview


• Measles vaccine




India: Lab supported measles outbreak surveillance

Linkage with program decisions


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Scale-up of laboratory supported measles outbreak surveillance

2006

2007

2010

2009

2011 (Planned)

Reporting of Clinical Measles cases linked with AFP weekly reporting in these states; Weekly aggregate data should be mutually shared with IDSP

One state level lab strengthened in each state. Lab testing for measles and rubella IgM.

Serologically confirmed# measles, rubella and mixed outbreaks, India (Andhra Pradesh, Gujarat, Karnataka, Kerala, Madhya Pradesh, Rajasthan, Tamil Nadu and West Bengal)

216 outbreaksMeasles outbreaks confirmed

Rubella outbreaks confirmed

Mixed outbreaks confirmed

685641

196 16 4

2009 2010*

165 outbreaks

#Outbreak confirmation for Measles: 2009 ≥ 1 cases IgM positive for measles, Similarly for Rubella Outbreak confirmation for Measles: 2010 ≥ 2 cases IgM positive for measles, Similarly for Rubella

* data as on 15th Apr, 2011

Widespread measles virus transmission

Low coverage Districts in high coverage states


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2008

Total cases- 2118

2009

Total cases- 464

Measles cases by age, 2008-2011, Gujarat

Cases from serologically confirmed measles and mixed outbreaks

% %

2010Total cases- 973

%

2011*Total cases- 710

%



24


Measles cases by age, 2008-2011, Madhya Pradesh

%

2008

No reporting in 2008

Cases from serologically confirmed measles & mixed outbreaks



2009


%


25

2008


Measles cases by age, 2008-2011, Rajasthan

%

2009


2010Total cases- 1141

%

Cases from serologically confirmed measles & mixed outbreaks* data as on 15th Apr, 2011

Total cases- 293%


26

N=213

Andhra Pradesh

Vaccinated Not Vaccinated Unknown

N=301

Gujarat

N=363

Tamil Nadu

N=686

Madhya Pradesh West Bengal

N=705

Karnataka

Measles cases (1-4 years) by vaccination status, 2010*

N=517

Rajasthan

N=680

Cases from serologically confirmed measles & mixed outbreaks

N=227

Kerala



27

N=195

Andhra Pradesh


N=457

Gujarat

N=311

Tamil Nadu

N=531

Madhya Pradesh

N=649

West Bengal

N=464

Karnataka

Measles cases (5-9 years) by vaccination status, 2010*

Cases from serologically confirmed measles outbreaks

N=442

Rajasthan

N=243

Kerala



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Bihar: Measles outbreak surveillance

• Processes for systematic surveillance initiated last month

• Data presented here based on outbreaks investigated ad-hoc per state Govt. request– All outbreaks investigated with laboratory testing

• 2008-2011: 5 fever & rash outbreaks investigated; all outbreaks lab confirmed to be measles– 527 cases, 16 deaths– Overall Case-fatality ratio: 3%

• Observed CFR should be interpreted in context of ad-hoc investigations


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Total cases- 202Outbreaks- 2

Total cases- 136Outbreak- 1

Total cases- 189Outbreaks- 2

2008 2010 2011

Measles cases by age, Bihar, 2008-2011*

Cases from serologically confirmed measles outbreaks

% %

* data as on 15th May, 2011

%


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Serologically confirmed measles outbreaks – Bihar, 2008-2011*Vaccination status of measles cases by age

N=22 N=219 N=235 N=37 N=14

1-4 years 5-9 years 10-14 years >=15 years


< 1 year

* data as on 15th May, 2011


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Case Fatality Ratios in lab confirmed measles outbreaks: catch-up campaign states

0

1

2

3

4

5

6

2006 2007 2008 2009 2010 2011

Gujarat Madhya Pradesh Rajasthan Bihar


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Overview


• Measles vaccine





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Measles outbreak surveillance: data informs program decisions

• Measles surveillance– Among 6 EPI diseases, most outbreak prone and easily

recognizable – Most cases are clinically manifest– Last EPI antigen in infant immunization schedule – Measles outbreaks flag areas with suboptimal infant

immunization coverage (measles and other antigens)• Summary of evidence from measles surveillance

– Lab evidence of measles transmission in all states– Mortality burden higher in catch-up campaign states (high burden

states)– Immunization status: largely a problem of “failure to vaccinate” in

catch-up campaign states– <10 year old children bear 90% of disease burden in catch-up

campaign states


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Summary• Highly infectious outbreak prone disease

• Highly effective (2 doses) live attenuated vaccine available

• Control and elimination strategies work if implemented properly in a sustained manner

• India: 2 dose strategies needed for all states– State specific delivery strategies

• Tasks ahead:– Implement 2-dose strategies (RI and SIA) fully and properly– expand lab supported surveillance in all catch-up campaign states

with full state ownership

Education

Measles surveillance sepio mtg 18 20 may 2011 (ab) v1