CSU 48/2009: THREE ON MEASLES

Friday, 14th of August 2009

CSU 48/2009: THREE ON MEASLES

 WHO has been working overtime on measles.  Item 1) is the WHO Secretariat's report to the WHO Executive Board on prospects for measles eradication.  Item 2) is the measles discussion and recommendations from the recent meeting of the Strategic Advisory Group of Experts (SAGE). Item 3) covers progress towards regional measles elimination in the Western Pacific Region, which includes China. 

 

Good reading.

 

Bob Davis

 
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1) GLOBAL MEASLES ELIMINATION

 

This report to the WHO Executive Board gives the current thinking of the WHO Secretariat on global measles elimination.

 

Text is also on the Net at apps.who.int/gb/ebwha/pdf_files/EB125/B125_4-en.pdf

 

EXECUTIVE BOARD EB125/4

125th Session 16 April 2009

Provisional agenda item 5.1

 

Global elimination of measles

 

Report by the Secretariat

 

1. The Executive Board at its 123rd session in May 2008 requested the Director-General to report

to the Board’s 125th session in May 2009 on the feasibility of global measles elimination1. This report

describes current efforts, status and challenges, as well as the feasibility of global elimination.

2. At present, there is no global goal for the elimination of measles. However, maintenance of, or

progress towards, elimination is being carried out at regional level. The WHO Region of the Americas

achieved regional measles elimination in 2002. Three WHO regions have also established elimination

goals: Eastern Mediterranean (2010), Europe (2010) and Western Pacific (2012). The WHO African

Region established a pre-elimination goal in 2008 that aims to reduce measles mortality by 98% by

2012 compared to 2000 estimates. The WHO South-East Asia Region is the only region without an

elimination or pre-elimination goal. It is currently focusing its efforts on achieving the global measles

mortality reduction goal.

 

SUCCESS OF MEASLES MORTALITY REDUCTION EFFORTS

3. Between 2000 and 2007, global measles mortality declined by 74% from an estimated 750 000

deaths in 2000 to 197 000 in 2007. The largest regional percentage reduction in estimated measles

mortality during this period occurred in the Eastern Mediterranean (90%) and African (89%) regions,

accounting for 16% and 63% of the global reduction in measles deaths, respectively. Global routine

coverage with the first dose of measles-containing vaccine (MCV) reached 82% in 2007, increasing

from 72% in 2000. In the 47 countries where measles is a priority (see Annex) and which accounted

for 98% of the total estimated number of deaths globally in 2007, vaccination coverage with the first

dose of MCV increased from 58% in 2000 to 72% in 2007.

1 See document EB123/2008/REC/1, summary record of the second meeting, section 1.

 

4. These public health accomplishments helped to prevent an estimated 3.6 million measles deaths

between 2000 and 2007. They were made possible by the concentrated focus of immunization partners

on controlling measles rapidly and through emphasis on regions with the highest levels of measles

mortality. The sharp decline in measles deaths is the direct result of: (a) commitment of Member

States severely affected by measles to provide better access to routine childhood immunization;

(b) Member States conducting measles supplementary immunization activities1 in which an estimated

576 million children aged nine months to 14 years were vaccinated against measles between 2000 and

2007 in the 47 priority countries; (c) technical and financial support provided through the Measles

Initiative, a partnership formed in 2001 and spearheaded by WHO, UNICEF, the American Red Cross,

the Centers for Disease Control and Prevention (Atlanta, Georgia, United States of America), and the

United Nations Foundation; and (d) implement effective laboratory-supported disease surveillance.

5. Measles mortality reduction efforts have been a major force for child survival. In 2008,

integrated supplementary immunization activities against measles resulted in the distribution of over

35 million doses of vitamin A, 30 million doses of deworming medicine and more than 5.6 million of

insecticide-treated bednets. This integration promotes greater health equity, reduces costs, improves

efficiency and contributes to the achievement of Millennium Development Goal 4, which aims to

reduce overall child deaths by two thirds by 2015 compared with the 1990 level.

 

REMAINING CHALLENGES IN MEASLES MORTALITY REDUCTION EFFORTS

6. Although estimated global routine vaccination coverage with the first dose of MCV reached

82% in 2007, this coverage – which is below the target of >90% – varied substantially by geographical

region. While the largest percent increase in routine coverage from 2000 to 2007 occurred in the

African and South-East Asia regions, the 2007 coverage estimates in these two regions remain at

<80%. Of the estimated 23.2 million infants in 2007 who missed receiving their first dose of MCV

through routine immunization services by the age of 12 months, 15.3 million (65%) reside in eight

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).

 

7. In 2007, there were an estimated 197 000 measles deaths globally, of which more than 90%

(177 000) occurred among children under the age of five. This figure can be reduced only if the

following serious conditions are met: (i) accelerated activities to reduce measles mortality need to be

successfully implemented in India, since it is the major contributor to the global disease burden of

measles; (ii) vaccination systems need to be improved to ensure >90% of infants worldwide are

vaccinated against measles through routine health services before their first birthday; (iii) priority

countries must continue conducting supplementary immunization activities every two to four years,

targeting children born since the last campaign until their routine immunization systems are capable of

reaching >90% of all children; and (iv) the funding gap – which currently stands at US $176 million

for 2009–2010, of which US $35 million is needed for 2009 – has to be filled.

1 Nationwide catch-up supplementary immunization activities target all children in a particular age group (most frequently children aged from nine months to 14 years) and have the goal of eliminating susceptibility to measles in the general population. Periodic follow-up activities target all children born since the last supplementary immunization activity.

Follow-up activities are generally conducted nationwide every two to four years and target children aged from 9 to 59 months, with the goal of eliminating any measles susceptibility that has developed in recent birth cohorts as well as protecting children who did not respond to their first measles vaccination.

 

REGIONAL MEASLES ELIMINATION GOALS: PROGRESS AND CHALLENGES

8. The WHO Region of the Americas interrupted indigenous transmission of measles virus in

2002, hence achieving the elimination of measles in the region. This major achievement was made

possible by the successful implementation of the measles–rubella vaccination strategy, which includes

improving routine immunization services and conducting supplementary immunization activities. As a

result, all countries in the region provide at least two doses of vaccine containing measles and rubella

antigens to their populations. High vaccination coverage attained through routine immunization and

supplementary immunization activities has reinforced measles elimination and brought the region

closer to achieving the regional goal of rubella elimination by 2010. The effective implementation of

the measles–rubella vaccination strategy has resulted in an historically low number of reported

measles cases – which ranges between 85 to 237 cases annually over the period 2003 and 2008

following importations from abroad. Given that measles remains endemic in other WHO regions, the

Region of the Americas is concerned with the risk of disease importations and needs to maintain its

elimination strategy and associated costs until all regions have eliminated measles.

 

9. The WHO Eastern Mediterranean Region achieved the global goal of a 90% reduction in

measles mortality in 2007 and has made good progress towards the 2010 regional measles elimination

goal. The region’s vaccination coverage with the first dose of MCV increased from 70% in 1997 to

84% in 2007 and measles incidence decreased by 83% from 146 cases/1 000 000 population in 1998

to 25 cases/1 000 000 population in 2007. However, the region may not achieve the goal of

eliminating measles by 2010 because measles outbreaks continue to occur in many countries in the

Region and the implementation of measles elimination strategy varies between countries. Establishing

comprehensive measles control activities has been difficult in a number of countries – notably

Afghanistan, Iraq, Pakistan, Somalia and Sudan – due to civil unrest, natural disasters and competing

public health priorities.

 

10. The WHO European Region has made considerable progress towards the 2010 regional measles

elimination goal. Measles incidence dropped to an historical low of <10 cases/1 000 000 population in

2007 and 2008. In addition, routine immunization coverage among children aged 12–23 months with

the first dose of MCV reached a high of 93% to 94% in 2007–2008, up from between 90% and 91% in

the 2000–2004 period. However, two substantial challenges remain towards achieving the elimination

goal: (1) suboptimal immunization, coverage with 32% of the countries in the region not achieving the

target coverage for the first dose of MCV of 95% in 2007 leading to continued outbreaks and the

resurgence of indigenous measles in some western European countries; and (2) setbacks in the

implementation of supplementary immunization activities in eastern Europe in 2008. Philosophical

and religious beliefs as well as misplaced concerns about vaccine safety are the principle barriers to

achieving measles elimination.

 

11. The WHO Western Pacific Region has made significant progress towards the 2012 regional

measles elimination goal. From 2005 to 2007, 15 out of 21 countries achieved at least 90% vaccination

coverage with the first dose of MCV. The number of countries using two routine doses of MCV has

increased to 31, up from 27 during the same period. In 2007 and 2008, seven priority countries –

Cambodia, China, Lao People’s Democratic Republic, Mongolia, Papua New Guinea, Philippines and

Viet Nam – conducted supplementary immunization activities. With the exception of Papua New

Guinea, all these countries achieved vaccination coverage of 95% or higher. Despite successes, major

challenges remain. The greatest burden of measles is in China and Japan, which account for 97% of all

measles cases in the Region. Both countries contribute greatly to the Region’s reported incidence of

81.5 cases/1 000 000 population in 2008. In addition, both countries have been experiencing large,

continuing measles epidemics. To improve coverage with the first dose of MCV in the Lao People’s

Democratic Republic and Papua New Guinea, the health infrastructure and case-based surveillance

have to be strengthened.

 

IS GLOBAL MEASLES ELIMINATION FEASIBLE?

12. Given that the global elimination of measles is an ambitious goal, a thorough and

comprehensive analysis of its feasibility and appropriateness needs to be undertaken. The Secretariat

has initiated a programme of work to examine the issues related to global measles elimination

including: (a) reviewing the biological aspects and cost–effectiveness of global elimination as well as

the current and future supply of measles vaccine; (b) examining the impact of global elimination

activities on the routine immunization programmes and national health systems; and (c) convening a

global consultation to review the evidence and assessments by experts on feasibility and

appropriateness of a global elimination goal. A report outlining the findings and recommendations will

be prepared for the Executive Board and the World Health Assembly in 2011.

 

ACTION BY THE EXECUTIVE BOARD

13. The Executive Board is invited to note the report.

 

ANNEX

MEASLES PRIORITY COUNTRIES

The 47 priority countries worst affected by measles are:

Afghanistan, Angola, Bangladesh, Benin, Burkina Faso, Burundi, Cambodia, Cameroon,

Central African Republic, Chad, Congo, Côte d’Ivoire, Democratic Republic of the Congo, Djibouti,

Equatorial Guinea, Eritrea, Ethiopia, Gabon, Ghana, Guinea, Guinea-Bissau, India, Indonesia, Kenya,

Lao People’s Democratic Republic, Liberia, Madagascar, Mali, Mozambique, Myanmar, Nepal, Niger,

Nigeria, Pakistan, Papua New Guinea, Rwanda, Senegal, Sierra Leone, Somalia, Sudan, Timor-Leste,

Togo, Uganda, United Republic of Tanzania, Viet Nam, Yemen and Zambia.

 

2) Meeting in Geneva in April, WHO’s Strategic Advisory Group of Experts (SAGE) reviewed the progress and setbacks of global efforts at measles mortality reduction and, in four regions, elimination.

 

Full text, in English and French,  is at www.who.int/wer/2009/wer8423.pdf

 

Measles

SAGE expressed grave concern about the considerable decline in funding for measles control since 2008. The responsibility for sustaining the impressive gains that have been made in reducing measles mortality lies both with international donors and national governments. If adequate resources are not guaranteed for programme activities planned for 2009 and beyond, a resurgence of measles will occur with an associated increase in mortality among young children that will jeopardize the achievement of Millennium Development Goal 4.

 

SAGE reviewed the findings from the working group on measles. The group’s analysis of countries’ experience combined with mathematical modelling has resulted in criteria that can be used by countries and regions to make rational decisions on: (i) when to start delivering a second dose of measles-containing vaccine through routine services (routine MCV2), (ii) the optimal age for administering routine MCV2, and (iii) when regular vaccination campaigns (also referred to as supplementary immunization activities, or SIAs) can be suspended in place of routine MCV2 immunization.

 

The following recommendations will be included in a revised WHO position paper on the use of measles vaccine.

 

MCV2 may be added to the routine immunization schedule in countries that have achieved ≥80% coverage of 1 dose of measles-containing vaccine (MCV1) nationally for 3 consecutive years, as determined by WHO and UNICEF estimates. Countries that do not meet this criterion should prioritize improving the coverage of V1 and conduct high-quality campaigns, rather than adding MCV2 to their routine schedule.

 

Since the addition of routine MCV2 covers only a single birth cohort and takes time to achieve high rates of

coverage, countries should not stop regular campaigns until high routine coverage of MCV2 has been achieved.

 

The accumulation of susceptible people should continue to be monitored subsequent to the introduction of routine MCV2 immunization, and a campaign should be conducted before the number of susceptible preschoolaged children reaches the size of a birth cohort.

 

Experience in the Region of the Americas has shown that measles elimination may be achieved with uniformly high coverage of MCV1 (>90–95%) and regular high-quality campaigns. Hence, the addition of routine MCV2 immunization is not an absolute requirement for achieving mortality reduction targets or stopping measles transmission. Nevertheless, a country may decide to add MCV2 to their routine schedule (while continuing campaigns) for one or more of the following reasons:

 

(i) to slow the accumulation of susceptible children, thereby lengthening the intercampaign interval;

(ii) to gradually decrease reliance on, and eventually stop, campaigns once high population immunity (>93–

95%) can be maintained with a routine 2-dose schedule alone; and (iii) to establish a well-child visit during the second year of life.

 

Before a country adds MCV2 to its routine schedule, a careful review should be conducted by a national immunization committee in consultation with WHO’s regional office or the regional ITAG, or both, to determine a suitable age for administration of this dose; to ensure an accurate denominator if administered at the time of school entry; to establish a system for recording doses both for the individual (for example, by using an immunization card) and for the health system (for example, by developing a vaccination register); and to conduct training for health staff to ensure the timely scheduling of doses and tracking of children who are not immunized.

 

Countries with ongoing measles transmission and MCV1 delivered at 9 months of age should administer

routine MCV2 at 15–18 months of age. The minimum interval between administering MCV1 and MCV2 is

1 month. Providing routine MCV2 immunization to children in their second year of life reduces the rate of

accumulation of susceptible children and the risk of measles outbreaks.

 

In countries with very low measles transmission (that is, those that are near elimination) that thus have a low

risk of measles infection among infants, MCV1 can be administered at 12 months of age to take advantage of the higher seroconversion rates achieved at this age compared with at 9 months of age. In this situation, the optimal age for administering routine MCV2 is based on programmatic considerations that enable achieving the highest population immunity to measles. Administration of MCV2 at 15–18 months ensures early protection of the individual, slows accumulation of susceptible young children and may correspond with a health visit for other routine health-care interventions. If coverage of MCV1 is high (>90%) and school enrolment is high (>95%), administration of routine MCV2 at school entry may be an effective strategy to achieve high coverage.

 

Regardless, a systematic effort to check vaccination status of all children at school entry is recommended to

ensure that they have received at least 2 doses of measles vaccine and other needed vaccines.

In countries that have relied on regular campaigns to achieve high population immunity, cessation of campaigns should be considered only when >90–95% vaccination coverage has been achieved nationally for both MCV1 and routine MCV2, as determined by the most accurate means available (for example, a well-conducted population-based survey or estimates made by WHO and UNICEF) for at least 3 consecutive years.

 

Before stopping campaigns, a review should be conducted by a national immunization committee in

consultation with WHO’s regional office or regional ITAG, or both. The committee should review the following:

historical vaccination coverage data (for MCV1, routine MCV2 and campaigns) both at the national and

district levels, the degree of heterogeneity of routine coverage among districts, the population immunity profi

le, the predicted rate of accumulation of susceptible people in the absence of campaigns, the epidemiology

of measles and the performance of the measles surveillance system.

 

Decisions regarding changes in measles immunization policy and schedules should be based on a review of

district-level data, and SAGE emphasized the importance of improving the quality both of district-level

information on vaccination coverage and disease surveillance. SAGE reviewed the programme of work aimed at establishing a global measles elimination goal, and discussed the most appropriate defi nition for “global measles elimination”. SAGE agreed that eradication is technically the correct term to describe worldwide interruption of measles transmission and the term “measles eradication” should be used instead of “global measleselimination”. SAGE approved the comprehensive programme of work planned to assess the feasibility of measles eradication, and noted the importance of careful and deliberate evaluation before embarking on a measles eradication programme. Furthermore, SAGE highlighted the need to ensure that resources are committed from WHO and from donors prior to setting a measles eradication goal.

 

 

 3) PROGRESS TOWARDS 2012 MEASLES ELIMINATION IN WESTERN PACIFIC

 

The Western Pacific Region, which includes China and Japan, is moving towards its 2012 regional elimination goal. Its progress, like that of the Americas, EURO, and most countries of the Eastern Mediterranean Region, will weigh in the balance if WHO’s governing bodies consider global eradication in their 2010 sessions. This recent update, from the Morbidity and Mortality Weekly Report, is available on the Internet at http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5824a4.htm

 

From the editorial note:

 'The WPR has made progress toward the 2012 regional goal of measles elimination as evidenced by increasing routine and SIA measles vaccination coverage and declining measles incidence in the presence of improving case-based, laboratory-supported measles surveillance systems. Nevertheless, in the region overall and in many countries, surveillance does not yet meet elimination standards, leading to underreporting or misclassification of cases. . . .

'Challenges also exist in China and Japan, which together accounted for 82% of the region's population and more than 97% of its reported measles cases in 2008. Both countries have made renewed commitments and plans for achieving the 2012 regional goal. China has strengthened routine measles vaccination by scheduling earlier administration of MCV2 (at age 18--24 months instead of 7 years), providing incentives to health-care workers for immunizing children, and requiring proof of receiving 2 doses of measles vaccine at school entry. Japan is implementing a national measles elimination plan established in December 2007.'

 

Progress Toward the 2012 Measles Elimination Goal --- Western Pacific Region, 1990--2008

 

In 2003, the World Health Organization (WHO) Regional Committee of the Western Pacific Region (WPR) formally declared a measles elimination goal* (1), and in 2005, the committee established a target date of 2012 for regional measles elimination (2). Key strategies recommended by WHO for achievement of measles elimination include 1) very high (≥95%) vaccination coverage with 2 doses of measles-containing vaccine (MCV1 and MCV2) through routine vaccination and/or supplemental immunization activities (SIAs)†; 2) high-quality case-based§ measles surveillance; and 3) access to an accredited measles laboratory network for testing of suspected measles cases and identification of measles virus genotypes. This report describes progress toward measles elimination in the WPR through 2008. Measles likely has been eliminated or nearly eliminated in 24 of the 37 countries and areas in the WPR (referred to in this report as countries). However, large numbers of measles cases continue to be reported from several countries. During 2008, a total of 131,441 confirmed measles cases (98.4 per million population) were reported from China and 11,015 cases (86.1 per million population) from Japan, two countries that account for 82% of the region's population and >97% of its confirmed measles cases. Intensified efforts by WPR countries, particularly China and Japan, will be required to achieve the 2012 goal.

 

Routine Vaccination

Among the 37 countries in the WPR,¶ 36 report administrative and, if available, survey data and their estimates of vaccination coverage among infants annually to WHO and the United Nations Children's Fund (UNICEF). The other country, Pitcairn Islands (with a population of approximately 50 persons), does not report data to WHO/UNICEF and is not included in this report. Based on these and other data available from published literature, WHO/UNICEF make their estimates of actual vaccination coverage for WHO member states (3). Regional MCV1 coverage by year was determined using WHO/UNICEF estimates of vaccination coverage and, when these estimates were not available (such as in certain areas of member states), coverage was determined using country estimates and weighting by country population size. Because China includes 75% of the region's population, its data are reported separately.

 

The history of measles elimination in the WPR can be divided into three periods: the period of measles control (1990--1995), the period of accelerated measles control (1996--2002), and the period of measles elimination (from 2003 to the present).** This report uses these three periods to describe progress toward measles elimination. Among the 35 WPR countries reporting (i.e., all WPR countries except China and Pitcairn Islands), mean regional MCV1 coverage was 80.8% during the period of measles control (1990--1995), increased to 89.0% during the period of accelerated control (1996--2002), and reached 91.6% during the period of measles elimination (2003--2008) (Figure). The WHO-estimated mean MCV1 coverage in China was 85.5%, 84.4%, and 88.8% during the same periods, but increased from 85% in 2003 to 94% in 2007 (data were not available for 2008). Among 36 countries (including China) reporting dose schedules in 2008, MCV1 was scheduled for administration at age <9 months in two (5.6%) countries, age 9 months in five (13.9%) countries,†† age 12 months in 26 (72.2%) countries, and age 15 months in three (8.3%) countries (Table 1).

 

Before 2003, few countries reported MCV2 coverage to WHO/UNICEF. During 2003--2008 (the period of measles elimination), the number of reporting countries varied annually from 16 to 24. These country estimates were used to determine the regional weighted MCV2 coverage by year. Mean MCV2 coverage (excluding China) during 2003--2008 was 84.2%. China's reported MCV2 coverage ranged from 84.1% to 96.4% during 2003--2007, with a mean of 92.5%. As of 2008, among the 30 countries that had scheduled administration of MCV2, 12 countries (40%) administered MCV2 at age 13--23 months, three (10%) at age 2 years, eight (26.7%) at age 4 years, one (3.3%) at age 5 years, five (16.7%) at age 6 years, and one (3.3%) at age 7 years.

 

Supplemental Immunization Activities

During the periods of measles accelerated control (1996--2002) and elimination (2003--2008), many countries conducted SIAs. Approximately 94.4 million children and adolescents in 28 WPR countries (excluding China) were vaccinated through SIAs. In China, SIAs during 2003--2008 reached approximately 101 million children and adolescents in 14 provinces (Table 2). SIA coverage generally has been higher since the region established an elimination goal. Excluding China, SIAs reached 87% of the target population in 25 countries during the period of measles accelerated control (1996--2002) and increased to 94% of the target population in 28 countries during the period of measles elimination (2003--2008). In China, SIA coverage by year during 2003--2008 was 95%--99%, with the exception of 2005. SIAs in the WPR were frequently used to provide vitamin A, oral polio vaccine, and anti-helminthics in addition to MCV.

Surveillance Activities

By 2008, all countries in WPR conducted case-based measles surveillance, supported by the measles and rubella laboratory network (LabNet), a network of 382 laboratories. Standard indicators for high-quality measles surveillance include 1) two or more suspected measles cases per 100,000 discarded as nonmeasles; 2) ≥80% of suspected measles cases with adequate investigations (i.e., investigations within 48 hours of rash onset that include all essential data elements); 3) ≥80% of suspected measles cases with clinical specimens collected within 28 days of rash onset; and 4) ≥80% of specimens with laboratory results available within 7 days after receipt in the laboratory (4,5). In 2008, the region's indicator achievements were 1.6, 47%, 62%, and 76%, respectively (6).

Genotypes of endemic measles virus identified among measles patients in the WPR since 2007 include D5 in Japan, D9 in Lao People's Democratic Republic, Malaysia, and New Zealand, and H1 in China, Hong Kong (China, Special Administrative Region [SAR]), and Vietnam. In addition, genotypes B3, D4, D8, and G3 were identified among measles patients; some of these genotypes were imported from other regions.

 

Monitoring Measles Incidence

Suspected measles cases can be confirmed by the laboratory (e.g., presence of anti-measles immunoglobulin M (IgM) antibodies in clinical specimens), by epidemiologic linkage to another confirmed case, and by clinical criteria (i.e., cases that satisfy the measles clinical case definition§§ and cannot be discarded as nonmeasles by laboratory or other criteria). Since 1990, the largest annual number of measles cases reported from the WPR (excluding China) was 106,172 (255.6 per million population) in 2000. In 2008, excluding China, 14,724 cases (32.6 per million) were reported, a decrease of 86%. (Figure). China reported 131,441 measles cases (98.4 per million) in 2008. A large outbreak in Japan resulted in over 18,000 (140.7 per million) reported cases in 2007 and 11,015 (86.1 per million) in 2008 (7). Excluding China and Japan, 3,564 measles cases (11.8 per million) were reported from the rest of the region in 2008. In descending order, the majority of these were from Cambodia (1,765), Philippines (880), Malaysia (333), Vietnam (258), and Lao People's Democratic Republic (117) (6).

 

Country Measles Elimination Status

Several WPR countries have achieved or nearly achieved the indicator targets suggesting substantial progress toward measles elimination. In 2006, Republic of Korea declared measles eliminated after having successfully implemented WHO-recommended strategies (8). In Australia, measles incidence has ranged from 0.5 to 6.1 per million since 2002; case investigations and genotype analysis indicated that the majority of these cases were imported or import-related (9). Reported routine vaccination coverage in Australia is high; however, sensitivity of suspected measles reporting is uncertain because surveillance performance is not monitored nationally. In Macau (China, SAR), fewer than five cases per year have been reported since 2001, corresponding to an annual incidence of zero to 8.3 per million; case investigations and genotype analysis of specimens during this period indicate that most of these cases were imported. In 2008, surveillance performance in Macau (China, SAR) satisfied all key indicator targets. All 21 Pacific island countries have reported zero measles cases in 2007 and 2008.

 

Reported by: Unit of Expanded Programme on Immunization, World Health Organization Regional Office of the Western Pacific, Manila, Philippines. Vaccines and Biologicals Dept, World Health Organization, Geneva, Switzerland. Global Immunization Div, Div of Viral Diseases, National Center for Immunization and Respiratory Diseases, CDC.

 

Editorial Note:

The WPR has made progress toward the 2012 regional goal of measles elimination as evidenced by increasing routine and SIA measles vaccination coverage and declining measles incidence in the presence of improving case-based, laboratory-supported measles surveillance systems. Nevertheless, in the region overall and in many countries, surveillance does not yet meet elimination standards, leading to underreporting or misclassification of cases. Moreover, countries such as Cambodia, Lao People's Democratic Republic, Papua New Guinea, and others face challenges to achieving the 2012 goal because of general weaknesses of public health services that result in low routine vaccination coverage. In such countries, continuing periodic SIAs to attain high MCV coverage while working to strengthen routine vaccination systems will be critical to achieve the goal. Ensuring that all suspected measles cases are identified, reported and fully investigated by providing training, adequate operational costs, and laboratory support is urgently needed to monitor progress toward and ultimately validate achievement of measles elimination. Monitoring of circulating measles genotypes also is needed to validate interruption of endemic measles virus transmission.

 

Challenges also exist in China and Japan, which together accounted for 82% of the region's population and more than 97% of its reported measles cases in 2008. Both countries have made renewed commitments and plans for achieving the 2012 regional goal. China has strengthened routine measles vaccination by scheduling earlier administration of MCV2 (at age 18--24 months instead of 7 years), providing incentives to health-care workers for immunizing children, and requiring proof of receiving 2 doses of measles vaccine at school entry. Japan is implementing a national measles elimination plan established in December 2007 (7).

Efforts to eliminate measles help strengthen health systems and reduce child mortality from pneumonia, diarrhea, and micronutrient deficiencies that occur after measles infection, thereby helping to achieve the United Nations' Millennium Development Goal No. 4 (to reduce by two thirds, from 1990 to 2015, the mortality rate in children aged <5 years).

 

¶¶ To achieve measles elimination and Millennium Development Goal No. 4, intensified and innovative efforts will be required by WPR countries and measles elimination partners*** to implement recommended strategies and target potentially new high-risk groups (e.g., young adults) revealed by epidemiologic analysis of surveillance data.

 

References

1.   World Health Organization. Fifty-fourth session of the Regional Committee for the Western Pacific. Summary record of the fifth meeting. Resolution WPR/RC54.R3. Expanded programme on immunization: measles and hepatitis B. Manila, Philippines: World Health Organization; 2003. Available at http://www.wpro.who.int/rcm/en/archives/rc54/rc_resolutions/wpr_rc54_r03.htm.

2.   World Health Organization. Fifty-sixth session of the Regional Committee for the Western Pacific. Summary record of the eighth meeting. Resolution WPR/RC56.R8. Measles elimination, hepatitis B control, and poliomyelitis eradication. Manila, Philippines: World Health Organization; 2005. Available at http://www.wpro.who.int/nr/rdonlyres/185af547-3c1a-4510-96f2-94d4402355e9/0/rc56_r08.pdf.

3.   World Health Organization. WHO-UNICEF estimates of MCV coverage. Available at http://www.who.int/immunization_monitoring/en/globalsummary/timeseries/tswucoveragemcv.htm.

4.   World Health Organization Regional Office of the Western Pacific. Monitoring measles surveillance and progress towards measles elimination. Measles Bulletin 2007;1:1--3. Available at http://www.wpro.who.int/nr/rdonlyres/7be6353c-7d82-4368-a300-57db3f38148d/0/measbulletinissue13.pdf.

5.   World Health Organization Regional Office of the Western Pacific. Field guidelines for measles elimination. Geneva, Switzerland: World Health Organization; 2004. Available at http://www.wpro.who.int/nr/rdonlyres/0f24b92e-ae2c-4c9b-b73b-e16acb833c35/0/fieldguidelines_for_measleselimination.pdf.

6.   World Health Organization Regional Office of the Western Pacific. Tables 2a and 2b. Measles Bulletin 2009;3:3--4 Available at http://www.wpro.who.int/nr/rdonlyres/fe4ce60a-5418-4a39-a666-0ce86aa4465e/0/measbulletinvol3issue1.pdf.

7.   CDC. Progress toward measles elimination---Japan, 1999--2008. MMWR 2008;57:1049--52.

8.   CDC. Elimination of measles---South Korea, 2001--2006. MMWR 2007;56:304--7.

9.   Heywood AE, Gidding HF, Riddell MA, et al. Elimination of endemic measles transmission in Australia. Bull World Health Organ 2009;87:64--71.

 

* Measles elimination is defined as the absence of endemic measles virus transmission.

 

† SIAs generally are carried out in two stages: 1) an initial nationwide catch-up SIA usually targets all children aged 9 months--14 years, followed by 2) periodic follow-up SIAs targeting all children born since the last SIA.

 

§ Data collected and reported on individual cases rather than in aggregate form.

 

¶ The WPR includes 37 countries and areas: Australia, Brunei Darussalam, Cambodia, China, Hong Kong (China, Special Administrative Region [SAR]), Macau (China, SAR), Japan, Malaysia, Mongolia, New Zealand, Lao People's Democratic Republic, Papua New Guinea, Philippines, Republic of Korea, Singapore, Vietnam, and 21 Pacific island countries and areas including American Samoa, Commonwealth of the Northern Marianas Islands, Cook Islands, Federated States of Micronesia, Fiji, French Polynesia, Guam, Kiribati, Marshall Islands, New Caledonia, Niue, Nauru, Pitcairn Islands, Samoa, Solomon Islands, Tokelau, Tonga, Tuvalu, Vanuatu, and Wallis and Futuna.

 

** Measles control aims to reduce the number of measles cases and deaths by 1) high (≥90%) coverage with a single dose of measles vaccine; 2) measles surveillance in every district with aggregate data reporting; and 3) case management with vitamin A and treatment for measles complications. Accelerated measles control aims to prevent measles outbreaks by providing a second dose of measles vaccine, often through campaigns, and conducting active measles surveillance with laboratory confirmation of suspected outbreaks. Measles elimination aims to interrupt transmission of measles by 1) very high (≥95%) coverage with 2 doses of measles vaccine through routine vaccination systems or SIAs; 2) high-quality case-based surveillance; and 3) access to an accredited measles laboratory network for confirmation of suspected measles cases and identification of measles genotypes.

 

†† Papua New Guinea also provides a supplementary dose of MCV at age 6 months.

 

§§ The WHO-recommended clinical case definition of measles is illness in a person of any age with fever, rash, and at least one of the following: cough, coryza, or conjunctivitis.

 

¶¶ Additional information available at http://www.un.org/millenniumgoals.

 

*** Current partners providing financial and technical support for measles elimination in the WPR include American Red Cross, Australian Agency for International Development, Government of Korea, Government of Japan, New Zealand Agency for International Development, CDC (United States), UNICEF, United Nations Foundation, and WHO.