Measles in W and C Africa

B Masresha

June 2019

Background

• Measles – highly contagious, preventable

• WHO recommends a 2-dose vaccination policy

• 85% seroconversion when given at 9 months

• Unprotected young children (unvaccinated PLUS those vaccinated but not seroconverting) accumulate with time

• Once the number of unprotected children reaches the size of a birth cohort, the risk of large outbreaks of measles increases• This happens once every 2 – 4 years in most countries (based on

the vaccination coverage rates)

• This explains why SIAs are done every 2 – 4 years, before the peak measles transmission season

Seasonality of measles transmission

• In the Sahel, incidence of all causes of febrile rash are clustered in first half of year

• This pattern is consistent throughout region

• Transmission peaking in the months after the end of the rainy season!

African Regional goal: Measles elimination by 2020

• >95% MCV1 coverage at national and district level

• > 95% SIAs coverage

• incidence of < 1 case / million population /year (excluding imported cases).

• Achieve the surveillance performance targets:• > 80% districts investigating one or more suspected measles

cases /year,

• a non measles febrile rash illness rate of > 2 per 100 000 population at national level.

4

DPT3, MCV1 and MCV2 coverage. WUENIC. African Region. 2000 - 2017

5

Number of countries by MCV1 coverage grouping. WUENIC. 2010 - 2017

6

M/ MR SIAs admin and survey coverage. 2017 - 2018

7

Measles cases and coverage. AFR. 1990 – 2017

• Measles control – elimination goal• Periodic SIAs

• Case based surveillance

Examples from Nigeria

Suspected Measles cases per week . Nigeria. 2016 – 2019 ( data as at week 18 of 2019)

0

500

1000

1500

2000

2500

Wk

01

Wk

02

Wk

03

Wk

04

Wk

05

Wk

06

Wk

07

Wk

08

Wk

09

Wk

10

Wk

11

Wk

12

Wk

13

Wk

14

Wk

15

Wk

16

Wk

17

Wk

18

Wk

19

Wk

20

Wk

21

Wk

22

Wk

23

Wk

24

Wk

25

Wk

26

Wk

27

Wk

28

Wk

29

Wk

30

Wk

31

Wk

32

Wk

33

Wk

34

Wk

35

Wk

36

Wk

37

Wk

38

Wk

39

Wk

40

Wk

41

Wk

42

Wk

43

Wk

44

Wk

45

Wk

46

Wk

47

Wk

48

Wk

49

Wk

50

Wk

51

Wk

52

Ca

se

s

Weeks

2016' 2017' 2018' 2019*

March/April 2019 OBR Borno

Trends of Measles cases. Nigeria. Jan 2016 - Apr 2019

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

Jan

-16

Fe

b-1

6

Ma

r-16

Ap

r-1

6

Ma

y-1

6

Ju

n-1

6

Ju

l-16

Au

g-1

6

Se

p-1

6

Oc

t-1

6

No

v-1

6

De

c-1

6

Jan

-17

Fe

b-1

7

Ma

r-17

Ap

r-1

7

Ma

y-1

7

Ju

n-1

7

Ju

l-17

Au

g-1

7

Se

p-1

7

Oc

t-1

7

No

v-1

7

De

c-1

7

Jan

-18

Fe

b-1

8

Ma

r-18

Ap

r-1

8

Ma

y-1

8

Ju

n-1

8

Ju

l-18

Au

g-1

8

Se

p-1

8

Oc

t-1

8

No

v-1

8

De

c-1

8

Jan

-19

Fe

b-1

9

Ma

r-19

Ap

r-19

2016 2017 2018 2019

Ca

se

s

Years

Lab-Confirmed EPI-LINK Compatible Discarded Pending

IMC Jan’2016 (South)

MVC Dec 2017 (Phase 1-S1 & 2 North)

MVC Apr 2018(Phase 2 South)

Jan 2017 OBR in Adamawa, Borno

and Yobe

March/April 2019 OBR Borno

12

Weekly trends of confirmed measles cases. Nigeria. Jan. 2015 - Nov. 2018

Northern States Southern States

• Nigeria has 42% - 44% MCV1 coverage (WUENIC) for the last 5 years!

L+E+C = Lab-confirmed + EpiLink + Clinical

Nigeria: Distribution of confirmed (L+E+C) Measles cases by age & vaccination status, Jan - Apr 2019

624

6183

1836

554348

0

2000

4000

6000

8000

10000

12000

9 - 11 Months' 12 - 59 Months' 5 - 9 Yrs' 10 - 14 Yrs' 15++ Yrs'

Ca

se

s

Age Group

Unknown 0 dose 1 Dose 2++ Dose

Examples from DRC

Evolution hebdomadaire de la notification des cas suspects de rougeole en RDC, 2010-2019 (sem.23)

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

5500

6000

6500

7000

7500

8000

1 1019283746 3 1221303948 5 1423324150 7 1625344352 9 18273645 2 1120293847 4 1322314049 6 1524334251 8 17263544 1 101928

2010 2011 2012 2013 2014 2015 2016 2017 2018 2019

Cas

no

tifi

és

Semaine epidémiologique par Anné

SUD-KIVUORIENTALENORD-KIVUMANIEMAKINSHASAKATANGAKASAI ORIENTALKASAI OCCIDENTEQUATEURBAS CONGOBANDUNDU

Classification des cas de Rougeole IgM+ par statut vaccinal et par groupe d’âge S1-23, 2019

894 cas IgM Positives Rougeole dont 69% des enfants ont moins de 5 ans.Statut vaccinal : 36% vaccinés, 15% non vaccinés et 49% inconnu.

0

50

100

150

200

250

300

350

400

450

500

0-9 mois 10-11mois 12-59mois 5-9ans 10-14ans >=15ans

Vaccinés Non Vaccines Inconnu

Common reasons for measles outbreaks

• Very low measles vaccination coverage (routine immunization and/ OR SIAs coverage)

• Sudden disruptions of vaccination services • EVD outbreak in W Africa 2014 - 2015

• Population displacement• Civil disturbances – eg., S Sudan, CAR

• Long term accumulation of susceptibles into older age groups ( eg Mauritania, Madagascar)

• Delays in the scheduled preventive SIAs• Recent examples: Chad, Burkina Faso, Benin, Cameroon

Relationship of measles outbreaks to the timing of SIAs

Trends in confirmed measles case reports in countries supported by MR catch-up SIAs – pre and post SIAs

Trends in confirmed measles case reports in countries supported by MR catch-up SIAs – pre and post SIAs

Trends in confirmed measles case reports in countries supported by M follow-up SIAs – pre and post SIAs

Trends in confirmed measles case reports in countries supported by M follow-up SIAs – pre and post SIAs

Incidence of confirmed measles and rubella per million population. AFR. 2010 - 2018

23

The challenges

• Routine immunization coverage plateauing

• Wide drop out rates between MCV1 and MCV2

• Delays and gaps in quality of SIAs

• Multiple public health priorities – inadequate attention/ funding for measles elimination

• Dependence on polio funding and staffing

• Inadequate resources for surveillance and lab support

• Inadequate preparedness to respond to outbreaks

The opportunities

• Regional elimination goal

• African countries that have attained near elimination status ( Ghana, Rwanda, Senegal, Eritrea, Zimbabwe, etc)

• Global and regional sensitivity to measles outbreaks – WHE involvement

• GAVI funding for SIAs

• Engagement of AU and Regional economic bodies

Way forward

• Support countries to improve routine immunisation (2 doses of measles vaccination)

• Timely periodic supplemental immunisationactivities (SIAs)

• Funded outbreak preparedness and response plans

• Early and aggressive outbreak response activities

• Use outbreaks as an opportunity to advocate for better leadership and ownership of vaccination programs