Measles Outbreak- Epidemiological analysis

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BTL

SNI

SVP

CDWBLG

SAG

CTP

RSN

KRG

MD L

STN

DHR

VDS

KND

PAN

SJP

HSB

DMH

SOP

SEH

RJG

UJN

SDL

JBP

DWS

SGL

GUNRWATKM

DDR

MDS

KTN

AKN

NSP

BRW

IDR

BHD

SDH

RTM

GLR

MRN

ANP

NMC

UMR

JBA

ALR HAR

BHP

BPL

DTA

• Blocks – 06• Population – 11,53,168• Area in Sq. Km. – 10,536

Sidhi- District information

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Timeline Measles Outbreaks

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9

3

0 0 0

99

374

180

2 2 10

50

100

150

200

250

300

350

400

0123456789

10

2010 2011 2012 2013 2014 2015

MOB Cases

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Timeline Measles Outbreaks

2

9

3

0 0 0

99

374

180

2 2 10

50

100

150

200

250

300

350

400

0123456789

10

2010 2011 2012 2013 2014 2015

MOB Cases

Measles Catch-up RoundCoverage: 95%

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District-SIDHI

KUSMI

SIHAWAL

RAMPUR NAIKIN

SE

MA

RIY

A

SIDHI

MAJHOLI

Rewa

Rewa (MP)

Singrauli (MP)

Sargija (CG)

Satna

Shahdol

06 Dec to 10 Dec 10

15 Aug to 14 Nov 10

14 Jan to 31 Jan 11

07 Jul to 18 Jul 11

05 Dec 10 to 22 Feb 11

12 Jan to 26 Feb 11

15 Sep to 01 Dec 11

09 Mar to 24 Mar 11

28 Sep to 16 Dec 11

27 Oct to 28 Nov 11

88/0

10/0

19/0

25 Feb to 10 Mar 11

5/0

5/0

42/0

14/0

117/2

70/078/0

MOB -2010MOB -2010 MOB-2011 MOB-2011 MOB-2012 MOB-2012

122/09/0

17/0

02 Jan to 10 Mar 12

08 Jan to 12 April 12

08 Apr to 18 Apr 12

35/0

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District-SIDHI

KUSMI

SIHAWAL

RAMPUR NAIKIN

SE

MA

RIY

A

SIDHI

MAJHOLI

Rewa

Mirzapur (UP)

Sonbhadra (UP)

Sargija (CG)

Satna

Shahdol

15 Sep to 01 Dec 11117/2

MOB -2010MOB -2010 MOB-2011 MOB-2011 MOB-2012 MOB-2012

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Block information:• Name: Sihawal• Population – 267,842• Area in Sq. Km.- 1589 sq

km

• Village information:• Population ~ 2600• Total Households- 523

KUSMI

SIHAWAL

RAMPUR NAIKIN

SEM

ARIY

A

SIDHI

MAJHOLI

Rewa

Singraoli

Sarguja (CG)

Satna

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Demographic Analysis

Gender Age distribution

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Vaccination status- Gender- Age

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Epi- Curve

Notification of Outbreak

Deaths

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Index case• Vaccinated, female, 60 mth old• Travel history to Nana’s place- day 30 to day 10

before onset • 2 more cases (8 yr- vaccinated, 6 mth- unvaccinated) in the

same household on day 2 and day 3 of development of rash in Index case

• Two cases (Index case and 8 yr old case)- participated in school before rash

• No clinical measles cases found at Nana’s place

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CFR

• Total Deaths= 2 (11 & 72 mth old)

• CFR= (2/ 117)* 100 = 1.71%

• Age-Specific CFR:– For </= 12 mth: 4.76%– For > 60 mth: 1.96%

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Positive Predictive Value

• 5 Blood specimens collected for IgM- Antibody• All the 5 specimens +ve for Measles IgM

• PPV of clinical case definition= 100%

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Attack Rate

• Population of the village: 2600• Birth rate of district (Sidhi rural): 26.7* *AHS 2012- 13

• Birth cohort: 70 births/ yr• Total Population <5 yr: 350

• Don’t have primary data to derive attack rate i.e. denominator

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Age-specific Attack rate

Age Population in age group

Cases in Age group Age-specific attack rate

</ = 12 mth 70 21 30% i.e. 30000/ 1L

13- 24 mth 70 14 20% i.e. 20000/ 1L

25- 60 mth 210 31 14.761% i.e. 14761/ 1L

61- 180 mth 586 51 8.703% i.e. 8703/ 1L

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Age-specific Attack rate

Age Population in age group

Cases in Age group

Age-specific attack rate

Vaccination Coverage in age-group

</ = 12 mth 70 21 30% i.e. 30000/ 1L

?

13- 24 mth 70 14 20% i.e. 20000/ 1L

?

25- 60 mth 210 31 14.761% i.e. 14761/ 1L

?

61- 180 mth 630 51 8.095% i.e. 8095/ 1L

?

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Attack Rate and Vaccine Efficacy• Measles vaccine coverage (Sidhi rural): 77.5%* *AHS 2012-13

• Total vaccinated children U- 5 yr**: 271• Total unvaccinated children U- 5 yr: 79

**calculations based on Birth rate and vaccination coverage as per AHS 2012- 13

Clinical Measles symptoms

Measles asymptomatic

Total

Unvaccinated**(**unknown=unvaccinated)

28 51 79

Vaccinated 38 233 271

Total 66 284 350

Vaccine Efficacy in U- 5

Attack rate unvaccinated- Attack rate vaccinated

--------------------------------------------------------------------------------------------------

Attack rate unvaccinated

= 70.3%

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Odds Ratio of developing clinical measles in U-5 UnVacc vs Vacc

(a/b)/ (c/d)= (28/ 51)/ (38/ 233) = 0.549/ 0.163

= 3.37

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Correlation- age and vaccination

Vaccinated Unvaccinated Total

</ = 60 mth 38(58%)

28(42%)

66

> 60 mth 15(29%)

36(71%)

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Chi- square test

Value p- value

Pearson Chi-square 9.209 0.002

Continuity correction 8.108 0.004

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Odd’s Ratio 95% CI

</ =60 mth old & vaccinated 1.958 (1.220- 3.141)

Vaccinated Unvaccinated Total

</ = 60 mth 38(58%)

28(42%)

66

> 60 mth 15(29%)

36(71%)

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Correlation- age and vaccination

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Correlation- gender and vaccination

Chi- square test

Value p- value

Pearson Chi-square 2.637 0.104

Continuity correction 2.068 0.150

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Vaccinated Unvaccinated Total

Male 21(38%)

35(62%)

56

Female 32(53%)

29(47%)

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Correlation- gender and vaccination

Odd’s Ratio 95% CI

female& vaccinated 1.399 (0.925- 2.116)

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Vaccinated Unvaccinated Total

Male 21(38%)

35(62%)

56

Female 32(53%)

29(47%)

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Age vs Gender

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Correlation- age and gender

</= 60 mth > 60 mth Total

Male 29(52%)

27(48%)

56

Female 37(60%)

24(40%)

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Chi- square test

Value p- value

Pearson Chi-square 0.934 0.334

Continuity correction 0.608 0.435

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Summary

• Delayed outbreak notification lead to spread of disease and preventable deaths

• Vaccine efficacy ??• Statistically significant correlation between

age and vaccination status• No significant correlation between vaccination

status- gender, and age- gender

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Recommendations (based on findings)

Summary Recommendations

Delayed outbreak notification Outbreaks must get notified in their early stages to prevent large epidemics and deaths

- Vaccine efficacy ??- Statistically significant correlation between age and vaccination

Reasons for high attack rate in < 60 mth old must be investigated

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Recommendations (future actions)

• Keeping a watch on contacts and reporting of cases as soon as they develop the rash

• Report and treat complications

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Key actionable insightsRecommendation Actionable insight

Early notification of outbreaks Capacity building of the health staff to identify measles cases early and report the same

High attack rate in <60 mth old -Vaccination coverage in <60 mth old- Regularity of vaccination sessions-Vaccination practices

Watch on contacts - Physician responsible for affected area to visit the same on every 4th day till “Zero” case reporting for 2 consecutive weeks

Reporting of complications -Training of health staff to identify Vit A deficiency, Pneumonia etc

Treatment of complications - Training of health staff to administer Vit A, antibiotics for pneumonia, supply of ORS- Zn

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