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Published Date: 2009-09-25 16:52:38
Subject: PRO/EAFR> Measles, control activities - Africa: 2000-2008
Archive Number: 20090925.202675

MEASLES, CONTROL ACTIVITIES - AFRICA: 2000-2008
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Date: Fri 25 Sep 2009
Source: MMWR Weekly 58(37);1036-1041 [edited]
http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5837a3.htm?s_cid=3Dmm5837a3_e

Progress Toward Measles Control -- African Region, 2001-2008
---------------------------------------------------------------------------=
------
In 2001, the countries of the World Health =

Organization (WHO) African Region (AFR) became =

part of a global initiative with a goal of
reducing the number of measles deaths by 50% by =

2005, compared with 1999. [The 46 African Region =

(AFR) countries are: Algeria, Angola,
Benin, Botswana, Burkina Faso, Burundi, Cameroon, =

Cape Verde, Central African Republic, Chad, =

Comoros, Congo, C=C3=B4te d'Ivoire, Democratic =

Republic of Congo, Equatorial Guinea, Eritrea, =

Ethiopia, Gabon, Gambia, Ghana, Guinea, =

Guinea-Bissau, Kenya, Lesotho, =

Liberia, Madagascar, Malawi, Mali, Mauritania, =

Mauritius, Mozambique, Namibia, Niger, Nigeria, =

Rwanda, Sao Tome and Principe, Senegal, =

Seychelles, Sierra Leone, South Africa, =

Swaziland, Togo, Uganda, United Republic of =

Tanzania, Zambia, and Zimbabwe. - mod.CP]

Recommended strategies for measles mortality =

reduction included 1) increasing routine =

coverage for the first dose of measles-containing
vaccine (MCV1) for all children, 2) providing a =

second opportunity for measles vaccination =

through supplemental immunization activities
(SIAs), 3) improving measles case management, and =

4) establishing case- based surveillance with =

laboratory confirmation of all suspected
measles cases (1). Before introduction of MCV =

throughout AFR, approximately 1 million measles =

cases had been reported each year in
the early 1980s (2). After strengthening =

measles-control activities, annual reported =

cases declined to an estimated 300 000--580 000 during
the 1990s. This report summarizes the progress =

made during 2001--2008 toward improving measles =

control in AFR. During 2001--2008 estimated MCV1 =

coverage increased from 57% to 73%, SIAs =

vaccinated approximately 398 million children, =

and reported measles cases decreased by 93%, from =

492, 116 in 2001 to 32, 278 in 2008. By 2005, =

global measles deaths had decreased by 60%, and =

the AFR goal had been achieved (3); AFR adopted =

a new goal to reduce deaths by 90%, compared with =

2000, and that goal was achieved in 2006 (3,4). =

However, inaccuracies in reported vaccination =

coverage exist, surveillance is suboptimal, =

and measles outbreaks continue to occur in AFR =

countries. Further progress in measles control =

will require full implementation of =

recommended strategies, including validation of =

vaccination coverage. Since the 1980s, AFR =

countries have reported measles =

vaccination coverage and the number of measles =

cases each year to the WHO African Regional =

Office (AFRO), using the WHO and United Nations =

Children's Fund (UNICEF) Joint Reporting Form. =

These data are collected through administrative =

reports from routine vaccination programs and =

SIAs and routine surveillance systems that =

provide aggregated case counts based on clinical =

diagnosis. Estimates of routine coverage with =

MCV1 are based on review of coverage data from =

administrative records, surveys, national =

reports, and consultation with local and regional =

experts. Coverage achieved during nationwide =

SIAs against measles are reported on the basis =

of the reported number of doses administered, =

divided by the target population.

In 1999, as part of the measles mortality =

reduction strategy, case- based surveillance with =

laboratory testing for all suspected =

measles cases was introduced with support from =

WHO AFRO. A suspected measles case is defined as =

1) any person with generalized maculo-papular rash
and fever plus cough or coryza or conjunctivitis =

or 2) any person in whom a clinician suspects =

measles. Each suspected measles case should be =

reported using an individual case-investigation =

form, and a blood specimen should be collected =

and sent to the laboratory for measles- specific =

immunoglobulin M testing. Laboratory confirmation =

of individual cases is discontinued after an =

outbreak has been confirmed as measles. An =

outbreak is confirmed when three or more =

measles laboratory-confirmed cases are detected in a health facility or
district in 1 month; subsequent cases are =

confirmed by epidemiologic link. An =

epidemiologic link is defined as a suspected measles case
that did not have a specimen collected for =

laboratory testing and is linked in person, =

place, and time to a laboratory-confirmed =

case (i.e., in a patient living in the same =

district or an adjacent district with a patient =

with laboratory-confirmed measles where =

a likelihood of transmission and onset of rash =

in the two patients within 30 days of each other =

exists) (5). Case-based surveillance data from =

AFR countries are shared regularly with WHO AFRO. =

Data quality is monitored using annualized =

performance indicators that include the =

1) percentage of districts reporting one or more =

suspected case with a blood specimen =

(target: >80%) and 2) nonmeasles febrile rash =

illness rate (target: >2 cases per 100,000).

Routine Vaccination Activities

In AFR, MCV1 is administered through routine =

services to children at age 9 months. According =

to WHO and UNICEF estimates, AFR MCV1 =

coverage increased from 57% in 2001 to 73% in =

2008. In 2008, among the 46 AFR countries, three =

(7%) had MCV1 coverage of <60%, 13 (28%) had =

coverage of 60%--69%, 11 (24%) had coverage of =

70--79%, 10 (22%) had coverage of 80--89%, and =

nine (20%) had coverage of =E2=89=A590% (Data tabulated =

in the original text). As of 2008, five (10%) =

countries provided a second dose of MCV (MCV2) =

through routine services: South Africa =

and Swaziland reported MCV2 coverage of 70%, =

Lesotho reported MCV2 coverage of 80%, and =

Algeria and Seychelles reported MCV2 coverage of >95% in 2008.

SIA Results

SIAs provide a second opportunity for measles =

immunization to all children, including those =

not vaccinated with MCV1 and those previously =

vaccinated; approximately 15% of children =

vaccinated with a single dose at age 9 months =

will not develop immunity to measles. The SIA =

strategy generally consists of a one-time =

catch-up SIA, targeted to a wide age range, =

which aims to reduce susceptibility to measles in
the population. This is followed by periodic =

follow-up SIAs targeting children born since the =

last SIA, thus reducing the accumulation of
susceptible children in new birth cohorts.

Before 2000, seven (15%) AFR countries (Botswana, =

Lesotho, Malawi, Namibia, South Africa, =

Swaziland, and Zimbabwe) had completed a catch- =

up SIA, and Namibia and South Africa had =

completed a follow-up SIA (6). By the end of =

2008, 43 AFR countries (all except Algeria,
Mauritius, and Seychelles) had completed a =

catch-up SIA, and all but Comoros and =

Guinea-Bissau had completed at least one follow-up SIA
(Data tabulated in the original text). During =

2001--2008, approximately 398 million children =

were vaccinated during measles SIAs in AFR: 237 =

million (60%) during catch-up SIAs in 34 =

countries, and 161 million (40%) during =

follow-up SIAs in 39 countries. Nine countries =

(Benin, Cameroon, Chad, the Democratic Republic =

of Congo, Ethiopia, Ghana, Niger, Nigeria, and =

Tanzania) conducted nationwide SIAs in phases =

covering different geographic areas implemented over 2 years.

Measles Surveillance

By December 2008, all AFR countries except =

Algeria, Comoros, Guinea Bissau, Mauritius, Sao =

Tome & Principe, and Seychelles had =

established measles case-based surveillance in =

accordance with the WHO AFRO measles =

surveillance guidelines (5). In 2008, of the 40 =

countries with case-based surveillance, 21 (53%) =

met the target of >80% of districts reporting =

one or more suspected cases; 24 (60%) had a non =

measles febrile rash illness rate of >2 cases =

per 100 000 population; and 16 (40%) met both targets.

Monitoring Measles Incidence

Following implementation of the measles mortality =

reduction strategies during 2001--2008, =

including introduction of case-based measles
surveillance, the number of reported measles =

cases decreased 93%, from 492 116 in 2001 to 32 =

278 in 2008 (Illustrated graphically in the
orignal text). Average annual measles incidence =

in AFR decreased 66%, from 50.2 per 100,000 =

population during 2001--2004 to 17.2 during
2005--2008 (Data tabulated in the original text). =

Despite this decrease, during 2005--2008, 14 =

countries reported outbreaks. Outbreak
field investigations conducted during 2003--2007 =

in South Africa (1676 cases, 2003--2005) (7), =

Kenya (2544 cases, 2005--2007) (8), and
Tanzania (1533 cases, 2006--2007) (9) found that =

failure to vaccinate was the primary cause. In =

2008, outbreaks also contributed to annual
case counts in Burkina Faso (395), Cameroon =

(495), the Democratic Republic of Congo =

(12,461), Ethiopia (3,511), Niger (1,317), and
Nigeria (9,960) (2).

MMWR Editorial Note

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

In 2008, after implementation of the measles =

mortality reduction strategy, routine measles =

vaccination coverage in AFR reached 73%,
SIAs were conducted in nearly all AFR countries, =

and reported measles cases decreased to a =

historic low of 32 278. According to previously
published WHO estimates, by 2006 AFR had achieved =

approximately 90% reduction in measles deaths, =

compared with 2000 (3). However, despite this =

progress, vaccination coverage reports remain =

imprecise, disease surveillance remains =

suboptimal, and outbreaks continue to occur, =

even in countries that reported implementation =

of all recommended components of the measles =

strategy. Available mathematical models likely =

overestimate the disease burden and =

underreporting of measles cases is common, even =

with high-performing surveillance =

systems; therefore, caution is recommended when =

drawing comparisons between reported incidence =

of measles and estimates of measles deaths generated from models.

SIAs are recommended to provide a second =

opportunity for immunization and increase the =

likelihood of vaccinating hard-to-reach children. =

SIA coverage usually is estimated by an =

administrative method relying on the reported =

number of vaccine doses administered and =

available target population denominator data, =

both of which often are imprecise. For example, =

during 2001--2008, several countries reported =

vaccinating >100% of children targets in SIAs. =

Improved methods for determining the actual =

target population size for SIAs are needed; =

reported coverage also should be routinely =

validated by independent surveys. In addition, =

detailed field investigations of outbreaks should be
undertaken to identify post-SIA risk factors for =

measles, and help refine vaccination strategies.

The findings in this report are subject to at =

least two limitations. First, a change in =

measles surveillance methods might result in
underestimates or overestimates of the disease =

burden over time. For example, in 1999, AFR =

countries routinely reported an aggregated
number of clinically diagnosed measles cases; =

however, after implementation of measles =

case-based surveillance, by 2005, most
countries had changed to reporting =

laboratory-confirmed measles cases (6). Second, =

although the case definition for suspected measles
remained the same, the change in measles =

reporting practices might have led to either =

underreporting, because of the additional resources
needed to complete individual case investigations =

and collect blood samples, or overreporting =

because of overall efforts to strengthen
measles surveillance.

In light of progress made toward reducing measles =

deaths, a more advanced goal was proposed =

recently for the region with several
recommendations to improve vaccination coverage =

and surveillance performance. The AFR measles =

technical advisory group met in May 2008 and =

recommended that AFR countries aim to meet the =

following targets by 2012: 1) reducing estimated =

measles deaths by 98%, compared with 2000 =

estimates; 2) reducing measles incidence to < 5 =

cases per 1 million population per year; 3) =

achieving 90% routine MCV1 coverage nationwide =

and >80% in all districts; 4) achieving >95% SIA =

coverage in all districts; and 5) attaining two =

primary measles surveillance performance =

indicator targets (a nonmeasles febrile rash =

illness rate of >2 cases per 100,000 population =

per year and one or more suspected measles case =

investigated with blood specimen in >80% of =

districts per year); and 6) routine reporting =

from all districts (10). The group also =

recommended that AFR countries consider =

introduction of MCV2 in the routine vaccination =

schedule if MCV1 coverage of >80% has =

been achieved and maintained for 3 consecutive =

years and at least one of the two primary =

measles surveillance indicator targets has =

been achieved and maintained for at least 2 =

years. For countries adopting a 2-dose routine =

measles vaccination schedule, continued follow-up =

SIAs were recommended for all new birth cohorts =

every 3--5 years until national MCV2 coverage of =

=E2=89=A590% is sustained for at least 2 years (10).

References
--------------
(1) World Health Organization and United Nations Children's Fund.
Measles mortality reduction and regional elimination---strategic plan,
2001--2005. Available at =

http://www.who.int/vaccines-documents/docspdf01/www573.pdf .
(2) World Health Organization. Measles reported cases. (Updated August
10, 2009). Available at < =

http://www.who.int/immunization_monitoring/en/globalsummary/timeseries/tsin=
cidencemea.htm =

>
(Accessed August 18, 2009).
(3) CDC. Progress in global measles control and mortality reduction,
2000--2006. MMWR 2007;56:1237--41.
(4) World Health Organization, Regional Office for Africa. Regional
strategic plan for the expanded programme on immunization, 2006--2009.
Available at =

http://www.afro.who.int/cah/documents/epi/afro_rc56_epi_sep_2006.pdf .
(5) World Health Organization Regional Office for Africa. Measles
surveillance guidelines. Available =

athttp://www.afro.who.int/measles/guidelines .
(6) CDC. Effects of measles-control activities---African Region,
1999--2005. MMWR 2006;55:1017--21.
(7) McMorrow M, Gebremedhin G, van den Heever J, et al. Measles
outbreak in South Africa, 2003--2005. S Afr Med J 2009;99:314--9.
(8) CDC. Progress in measles control---Kenya 2002--2007. MMWR
2007;56:969--72.
(9) Goodson JL, Wiesen E, Perry RT, et al. Impact of measles outbreak
response vaccination campaign in Dar es Salaam, Tanzania. Vaccine
2009;27:5870--4.
(10) World Health Organization Regional Office for Africa. Report of
the second meeting of the African regional measles technical advisory
group (TAG). Available at =

http://www.afro.who.int/measles/2ndtagmeeting/final_report.pdf .

--

Communicated by:

ProMED-mail <promed@promedmail.org>

[In the light of the remarkable progress achieved toward reducing the
incidence of measles and the number of measles deaths in the African
Region, more advanced goals are now being proposed which include
reducing estimated measles deaths by 98%, compared with 2000
estimates, and reducing measles incidence to < 5 cases per 1 million
population per year by 2012. A formidable medical and logistic
challenge. - Mod.CP]

See Also