GLOBAL PROGRESS IN MEASLES CONTROL AND MEASLES MORTALITY REDUCTION
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CSU 53/2008: GLOBAL PROGRESS IN MEASLES CONTROL AND MEASLES MORTALITY
REDUCTION
For those observing Eid, Hanukkah or Christmas this month, the item below
is a nice holiday gift.According to Dabbagh and fellow authors, '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%) were averted as a result of accelerated activities.' Internet
users should go to http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5748a3.htm ,
which gives both text and graphics.
It is hard to quantify the impact on measles mortality of IMCI. During a
recent field trip, I learned that Nigeria estimates a recent decline in its
measles case fatality rate from 3 to 1.7 percent, primarily because of
improved case management. Two doses of vitamin A on Days 1 and 2 of
treatment can have an impact on CFR.
So overall, the news is good. Still, without wanting to rain on anyone's
parade, we have to note that there are two flies in this ointment:
1) the 197,000 estimated measles deaths for 2007 include 125,000 from
India, which is unlikely to complete catch-up campaigns in all states and
Union territories by end 2010, the year of the GIVS target for measles
mortality reduction. Global measles mortality will go down and stay down
only when all countries complete their catch-up campaigns and continue with
well executed follow-up campaigns and routine immunization.
2) building on recent gains in Africa means more contributions from African
governments, now responsible for 50 percent of the operations costs in
their follow-up campaigns, and sustained contributions to Africa and
elsewhere from traditional donors, now in their worst economic crisis since
1929.
For those with regional interests, I am attaching the WHO/AFRO update from
this month's Task Force on Immunization.
By the time of next year's World Health Assembly, May 2009, we may have the
groundwork for a WHA resolution on global measles eradication.
So let us rejoice, but prudently.
Good reading,
Bob Davis
Progress in Global Measles Control and Mortality Reduction, 2000--2007
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% 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 comprehensive strategy for measles mortality reduction ()1.)
focuses on 47 priority countries.* The strategy's components include 1)
achieving and maintaining high coverage (90%) with the routinely scheduled
first dose of measles-containing vaccine (MCV1) among children aged 1 year;
2) ensuring that all children receive a second opportunity for measles
immunization (either through a second 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% decrease
in the estimated number of measles deaths globally. An estimated 197,000
deaths from measles occurred in 2007; of these, 136,000 (69%) 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
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% in 2007; however,
coverage has varied substantially by geographic region (Table 1). Of 23.3
million infants in 2007 who missed receiving their first dose of measles
vaccine through routine immunization services by the age of 1 year, 15.2
million (65%) resided in eight 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 second 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%) of these 47
countries conducted SIAs, reaching approximately 91 million children; 16
(80%) of these SIAs integrated at least one other child-survival
intervention (e.g., insecticide-treated bed nets, vitamin A supplements,
and deworming medication) (),Table 2).
Surveillance Activities
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%) of the
193 WHO member states had implemented case-based surveillance, compared
with 120 (62%) countries in 2004 (the first year for which data are
available). In 2007, 178 countries (92%), compared with 168 countries (88%)
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% decrease).
All regions reported a decrease in reported measles cases, with the highest
percentage reduction occurring in the Americas** and the African regions
(93% and 85%, respectively), and the lowest in the South-East Asian Region
(12%). 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
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%, from an estimated 750,000 deaths in 2000 to 197,000 deaths in 2007 (
Table 1, Figure:). Approximately 90% of estimated measles deaths occurred
among children aged <5 years: 679,000 (95% 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%) and African (89%)
regions, accounting for 16% and 63% of the global reduction in measles
mortality, respectively. The 47 priority countries accounted for 98% of the
total estimated number of deaths globally in 2007, whereas the reduction in
measles deaths among these countries accounted for 96% 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%) were averted as a result of accelerated activities
(i.e., 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.
Editorial Note:
During 2007, further progress was made toward achieving the 2010 global
measles mortality reduction goal of a 90% 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% 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% of the decline. However, a number of
countries have experienced outbreaks of more than 1,000 cases in 2007
(e.g., 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% 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 (e.g., the GAVI Alliance 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% reduction in global measles
mortality by 2010, major challenges should be addressed. First, accelerated
measles mortality reduction activities (e.g., 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 90% 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 (e.g., 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% measles mortality reduction by 2010.
References
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/docspdf01/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/docspdf05/givs_final_en.pdf.
3. CDC. Progress in reducing global measles deaths, 1999--2004. MMWR
2006;55:247--9.
4. CDC. Progress in global measles control and mortality reduction,
2000--2006. MMWR 2007;56:1237--41.
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_monitoring/routine/immunization_coverage/en/index4.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/docspdf01/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.
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/publications/wpp2006/English.pdf.
9. CDC. Progress in measles control---Kenya, 2002--2007. MMWR
2007;56:969--72.
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/0,1077,0_314_8274,00.html.
* Afghanistan, Angola, Bangladesh, Benin, Burkina Faso, Burundi, Cambodia,
Cameroon, Central African Republic, Chad, Côte d'Ivoire, Democratic
Republic of the Congo, Djibouti, Equatorial Guinea, Eritrea, Ethiopia,
Gabon, Ghana, Guinea, Guinea-Bissau, India, Indonesia, Kenya, Laos,
Liberia, Madagascar, Mali, Mozambique, Myanmar, Nepal, Niger, Nigeria,
Pakistan, Papua New Guinea, Republic of the Congo, Rwanda, Senegal, Sierra
Leone, Somalia, Sudan, Timor-Leste, Togo, Uganda, Tanzania, Vietnam, Yemen,
and Zambia.
† SIAs generally are carried out using two approaches. An initial,
nationwide catch-up SIA targets all children aged 9 months--14 years; it
has the goal of eliminating susceptibility to measles in the general
population. Periodic follow-up SIAs then target all children born since the
last SIA. Follow-up SIAs generally are conducted nationwide every 2--4
years and target children aged 9--59 months; their goal is to eliminate any
measles susceptibility that has developed in recent birth cohorts and to
protect children who did not respond to the first measles vaccination.
§ Second opportunity for immunization is provided to all children,
including those who were not reached with MCV1 and those who were
previously vaccinated (because approximately 15% of children vaccinated
with a single dose at age 9 months will fail to develop immunity to
measles).
¶ Case-based surveillance includes investigation of every suspected measles
case and routine reporting of detailed epidemiologic and laboratory data
for each confirmed measles case.
** The Region of the Americas interrupted indigenous measles transmission
in November 2002; cases reported since 2002 are imported or linked to
importation.
†† The Measles Initiative comprises the American Red Cross, CDC, the United
Nations Foundation, UNICEF, and WHO.