MEASLES ERADICATION - WORLDWIDE: UPDATE 2000-2007
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Date: Fri 5 Dec 2008
Source: CDC. MMWR Morb Mortal Wkly Rep 2008; 57(48 ): 1303-6 [edited]
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http://www.cdc.gov/mmwr/preview/mmwrhtm ... mm5748a3_e>
Progress in global measles control and mortality reduction, 2000-2007
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Despite the availability of a safe and effective vaccine since 1963,
measles has been a major killer of children in developing countries
(causing an estimated 750 000 deaths as recently as 2000), primarily
because of underutilization of the vaccine (1). At the World Health
Assembly in 2008, all World Health Organization (WHO) member states
reaffirmed their commitment to achieving a 90 percent reduction in
measles mortality by 2010 compared with 2000, a goal that was
established in 2005 as part of the Global Immunization Vision and
Strategy (2). This WHO-UNICEF (UN Children's Fund) comprehensive
strategy for measles mortality reduction (1) focuses on 47 priority
countries. The strategy's components include 1) achieving and
maintaining high coverage (greater than 90 percent) with the
routinely scheduled 1st dose of measles-containing vaccine (MCV1)
among children aged 1 year; 2) ensuring that all children receive a
2nd opportunity for measles immunization (either through a 2nd
routine dose or through periodic supplementary immunization
activities [SIAs]); 3) implementing effective laboratory-supported
disease surveillance; and 4) providing appropriate clinical
management for measles cases. This report updates previously
published reports (3,4) and describes immunization and surveillance
activities implemented during 2007. Increased routine measles vaccine
coverage and SIAs implemented during 2000-2007 resulted in a 74
percent decrease in the estimated number of measles deaths globally.
An estimated 197 000 deaths from measles occurred in 2007; of these,
136 000 (69 percent) occurred in the WHO South-East Asian Region.
Achievement of the 2010 goal will require full implementation of
measles mortality reduction strategies, especially in the WHO
South-East Asian Region.
Immunization activities
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WHO and UNICEF use data from administrative records and surveys to
estimate routine MCV1 coverage among children aged 1 year (5).
Coverage levels achieved during measles SIAs are estimated using the
reported number of doses administered and dividing by the target
population.
According to WHO and UNICEF estimates, global routine MCV1 coverage
has continued to improve steadily since 2000, reaching 82 percent in
2007; however, coverage has varied substantially by geographic region
(data tabulated in the original report). Of 23.3 million infants in
2007 who missed receiving their 1st dose of measles vaccine through
routine immunization services by the age of 1 year, 15.2 million (65
percent) resided in 8 highly populated countries: India (8.5 million
children), Nigeria (2.0 million), China (1.0 million), Ethiopia (1.0
million), Indonesia (0.9 million), Pakistan (0.8 million), the
Democratic Republic of the Congo (0.6 million), and Bangladesh (0.5
million)
During 2000-2007, a 2nd opportunity for measles immunization was
provided in the 47 priority countries to approximately 576 million
children aged 9 months-14 years through SIAs. In 2007, 20 (43
percent) of these 47 countries conducted SIAs, reaching approximately
91 million children; 16 (80 percent) of these SIAs integrated at
least one other child-survival intervention (such as,
insecticide-treated bed nets, vitamin A supplements, and deworming
medication) (data tabulated in the original report).
Surveillance activities
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Effective surveillance for measles entails establishing case-based
surveillance that includes case investigation and laboratory testing
of samples from all suspected measles cases (6). In 2007, 162 (84
percent) of the 193 WHO member states had implemented case-based
surveillance, compared with 120 (6 percent) countries in 2004 (the
1st year for which data are available). In 2007, 178 countries (92
percent) compared with 168 countries (88 percent) in 2000, reported
measles surveillance data to WHO and UNICEF through the annual Joint
Reporting Form. Worldwide, the number of reported measles cases
decreased from 852 937 in 2000 to 279 006 in 2007 (a 67 percent
decrease). All regions reported a decrease in reported measles cases,
with the highest percentage reduction occurring in the Americas and
the African regions (93 percent and 85 percent, respectively), and
the lowest in the South-East Asian Region (12 percent). The WHO
measles and rubella laboratory network, which in 1998 consisted of
fewer than 40 laboratories, by the end of 2007 had expanded to 679
national and subnational laboratories providing support for measles
and rubella surveillance in 164 countries.
Mortality estimates for 2007
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Despite the progress made on measles surveillance and reporting
globally, measles incidence remains underreported, and complete and
reliable surveillance data on the number of measles deaths are
lacking for many countries, particularly those with the highest
disease burden. To estimate measles mortality, WHO used the published
natural history model (7) and updated it with 1) the most recent
time-series of population data (8 ), 2) WHO-UNICEF routine
immunization coverage estimates and reported coverage of SIAs, and 3)
measles incidence as reported to WHO. This process produced the 2007
mortality estimates and permitted updating of previous estimates for
2000-2006.
During 2000-2007, global mortality attributed to measles was reduced
by 74 percent, from an estimated 750 000 deaths in 2000 to 197 000
deaths in 2007 (data tabulated and illustrated graphically in the
original text). Approximately 90 percent of estimated measles deaths
occurred among children aged less than 5 years: 679 000 (95 percent
uncertainty interval: 490 000-890 000) in 2000 and 177 000 (126
000-240 000) in 2007. The largest regional percentage reduction in
estimated measles mortality during 2000-2007 occurred in the Eastern
Mediterranean (90 percent) and African (89 percent) regions,
accounting for 16 percent and 63 percent of the global reduction in
measles mortality, respectively. The 47 priority countries accounted
for 98 percent of the total estimated number of deaths globally in
2007, whereas the reduction in measles deaths among these countries
accounted for 96 percent of the global reduction in measles deaths
during 2000-2007.
During 2000-2007, approximately 11 million measles deaths worldwide
were averted because of measles control activities; of these, an
estimated 3.6 million deaths (33 percent) were averted as a result of
accelerated activities (that is, increases in routine vaccination
coverage and implementation of measles SIAs).
[Reported by: A Dabbagh, PhD, M Gacic-Dobo, D Featherstone, PhD, P
Strebel, MBChB, JM Okwo-Bele, MD, Dept of Immunization, Vaccines, and
Biologicals, World Health Organization, Geneva, Switzerland. E
Hoekstra, MD, P Salama, MD, United Nations Children's Fund, New York,
New York. A Uzicanin, MD, Global Immunization Div, National Center
for Immunization and Respiratory Diseases, CDC.]
MMWR Editorial note
-------------------
During 2007, further progress was made toward achieving the 2010
global measles mortality reduction goal of a 90 percent reduction in
measles mortality compared with 2000. Increased MCV1 coverage,
together with the accelerated efforts to vaccinate children through
SIAs during 2000-2007, resulted in a 74 percent decrease in the
estimated number of measles deaths globally during this period.
The largest percentage decrease in estimated measles deaths occurred
in the Eastern Mediterranean Region, which appears to have already
met the 2010 goal. An important contributor to the rapid reduction in
measles mortality in the Eastern Mediterranean Region during 2007 is
the intensification of SIAs in the region, which resulted in more
than twice the number of children reached through SIAs in 2007
compared with 2006. The African Region was the largest contributor to
the global decline in measles mortality, accounting for 63 percent of
the decline. However, a number of countries have experienced
outbreaks of more than 1000 cases in 2007 (such as, the Democratic
Republic of Congo, Nigeria, Uganda, and Tanzania) because of gaps in
MCV1 coverage and children missed during SIAs. The reduction in the
South-East Asian Region was substantially smaller because India,
which alone accounts for 67 percent of the region's population, has
not yet begun large-scale measles SIAs.
The number of reported measles cases also declined by approximately
two thirds worldwide during 2000-2007. However, direct comparisons
between trends in estimated deaths and trends in reported cases
should be made with caution because the static model used to estimate
deaths does account for the cyclical nature of measles (7).
Furthermore, measles incidence is grossly underreported, and the
mathematical model used to estimate global measles mortality adjusts
for underreporting of cases (7).
The prevention of an estimated 3.6 million additional deaths during
2000-2007 because of accelerated measles control activities
highlights the potential future benefits of continuing the ongoing
efforts of the Measles Initiative and international partners (such
as, the GAVI Alliance [formerly The Global Alliance for Vaccines and
Immunization] and the International Finance Facility for
Immunization) to support country efforts to strengthen routine
immunization and implementation of SIAs. In addition to the primary
objective, measles SIAs provide the platform for delivery of other
child survival interventions, which attracts high-level political
support, allows for resources to be pooled, and increases community
participation (9).
As countries with high measles disease burden approach the Global
Immunization Vision and Strategy goal of a 90 percent reduction in
global measles mortality by 2010, major challenges should be
addressed. First, accelerated measles mortality reduction activities
(such as, SIAs coupled with further efforts to improve routine MCV1
coverage) need to be successfully implemented in the South-East Asian
Region, especially in India, which contributes substantially to the
global burden of measles. Second, to sustain the current reduction in
measles deaths, vaccination systems need to be improved to ensure
that more than 90 percent of infants receive their MCV1 on schedule.
Third, countries need to monitor accumulation of susceptible children
(by evaluating routine MCV1 and SIA coverage data by birth cohort)
and conduct follow-up SIAs when the number of susceptible children
approaches the size of a birth cohort. Fourth, disease surveillance
systems need to be strengthened at all levels to enable case-based
surveillance with testing of clinical specimens from all suspected
cases. Fifth, measles case management should be improved (such as, by
including use of vitamin A). Finally, further efforts are needed to
ensure sustainability of measles control activities. Recent
shortfalls in the donor funds available to support measles mortality
reduction activities (10) make increased country responsibility and
political commitment critical for both achieving and sustaining the
goal of a 90 percent measles mortality reduction by 2010.
References
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1. World Health Organization, United Nations Children's Fund: Measles
mortality reduction and regional elimination strategic plan
2001-2005. Geneva, Switzerland: World Health Organization; 2001.
Available at
<
http://www.who.int/vaccines-documents/d ... www573.pdf>.
2. World Health Organization: Global immunization vision and strategy
2006-2015. Geneva, Switzerland: World Health Organization; 2005.
Available at
<
http://www.who.int/vaccines-documents/d ... nal_en.pdf>.
3. CDC. Progress in reducing global measles deaths, 1999-2004. MMWR
2006; 55: 247-9. Available at
<
http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5509a8.htm>.
4. CDC. Progress in global measles control and mortality reduction,
2000-2006. MMWR 2007; 56: 1237-41. Available at
<
http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5647a3.htm>.
5. World Health Organization, United Nations Children's Fund:
WHO/UNICEF review of national immunization coverage, 1980-2006.
Geneva, Switzerland: World Health Organization; 2007. Available at
<
http://www.who.int/immunization_monitor ... ndex4.html>.
6. World Health Organization: Module on best practices for measles
surveillance. Geneva, Switzerland: World Health Organization; 2001.
Available at
<
http://www.who.int/vaccines-documents/d ... www617.pdf>.
7. Wolfson L, Strebel P, Gacic-Dobo M, et al: Has the 2005 measles
mortality reduction goal been achieved? A natural history modelling
study. Lancet 2007; 369: 191-200. Abstract available at
<
http://www.thelancet.com/journals/lance ... X/abstract>.
8. United Nations Secretariat, Population Division, Department of
Economic and Social Affairs: World population prospects: the 2006
revision. New York, NY: United Nations Secretariat; 2007. Available at
<
http://www.un.org/esa/population/public ... nglish.pdf>.
9. CDC: Progress in measles control - Kenya, 2002-2007. MMWR 2007;
56: 969-72. Available at
<
http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5637a5.htm>.
10. American Red Cross: Urgent funding needed to reach the 2010
measles goal. Washington, DC: American Red Cross; 2008. Available at
<
http://www.redcross.org/pressrelease/0, ... 74,00.html>.
--
Communicated by:
ProMED-mail
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[A 74 percent decrease in the estimated number of measles deaths
globally was estimated to have occurred during the period 2000-2007,
and the number of reported measles cases declined by approximately
two thirds worldwide during this period. This represents a remarkable
organisational achievement. It may become increasingly difficult,
however, to maintain from now on comparable progress toward achieving
the 2010 global measles mortality reduction goal of a 90 percent
reduction in measles mortality compared with 2000. The graphical
illustration (not shown above) appended to the text shows that the
curve for the estimated number of measles deaths by year since 2000
is flattening and indeed the estimated numbers of deaths in 2006 and
2007 were not statistically different. - Mod.CP]
