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Progress Toward Measles Elimination — Western Pacific Region, 2009–2012

In 2005, the World Health Organization (WHO) Regional Committee for the Western Pacific Region (WPR) resolved that WPR should aim to eliminate measles* by 2012 (1). The recommended measles elimination strategies (2) in WPR include 1) achieving and maintaining high (≥95%) coverage with 2 doses of measles-containing vaccine (MCV) through routine immunization services and by implementing supplementary immunization activities (SIAs), when required; 2) conducting high-quality, case-based measles surveillance; 3) ensuring high-quality laboratory surveillance, with timely and accurate testing of specimens to confirm or discard suspected cases and detect measles virus for genotyping and molecular analysis; and 4) establishing and maintaining measles outbreak preparedness for rapid response and ensuring appropriate case management. This report updates the previous report (3) and describes progress toward eliminating measles in WPR during 2009–2012. During this period, measles incidence reached a historic low, decreasing by 83%, from 34.0 to 5.9 cases per million population. However, to achieve measles elimination in WPR, additional efforts are needed to strengthen routine immunization services in countries and areas with <95% coverage with the routine first (MCV1) or second dose of MCV (MCV2), to introduce a MCV2 dose in the four remaining countries and areas that do not yet have a routine 2-dose MCV schedule, and to use SIAs to close immunity gaps among measles-susceptible populations in countries and areas that have ongoing measles virus transmission.

Immunization Activities

Annual data on MCV coverage are reported from 36 of the 37 WPR countries and areas to WHO and the United Nations Children's Fund (UNICEF). MCV1 coverage in WPR increased from 96% in 2009 to 98% in 2012. The number of countries with ≥95% MCV1 coverage increased from 12 (33%) in 2009 to 15 (42%) in 2012. MCV1 was administered at 8 months in one (3%), at age 9 months in six (17%),§ at age 10 months in one (3%), at age 12 months in 24 (67%), and at age >12 months in four (11%) (Table 1).

The number of countries and areas that provide routine MCV2 increased from 32 (89%) in 2009 to 33 (92%) in 2012, and the number reporting ≥95% MCV2 coverage increased from 10 (28%) in 2009 to 11 (31%) in 2012. Among the 33 countries and areas reporting MCV2 coverage in 2012, the scheduled age of MCV2 administration ranged from 12 months to 7 years. During 2009–2012, approximately 226 million children were vaccinated during 16 measles SIAs (Table 2); of these, seven (44%) SIAs included rubella vaccine, and 10 (63%) added at least one other child health intervention.

Surveillance Activities

During 2009–2012, measles case-based surveillance was conducted in all 37 WPR countries and areas, including 14 countries and two areas that report data individually, and 21 countries and areas of the Pacific Islands that report data as one epidemiologic block. Measles surveillance data are reported monthly to WHO and supported by 385 laboratories participating in the WHO Global Measles and Rubella Laboratory Network** (4). Suspected measles cases were confirmed based on laboratory findings, an epidemiologic link, or clinical criteria.†† Key indicators of surveillance performance include 1) the number of suspected measles cases discarded as nonmeasles (target: ≥2 per 100,000 population); 2) the proportion of second-level administrative units with ≥1 nonmeasles discarded case per 100,000 population (target: ≥80%); 3) the percentage of suspected measles cases with adequate investigation that includes all essential data elements§§ (target: ≥80%); 4) the percentage of suspected measles cases with adequate specimens collected within 28 days of rash onset (target: ≥80%, excludes epidemiologically linked cases) (5); and 5) the percentage of specimens with laboratory results available within 7 days after receipt in the laboratory (target: ≥80%). The number of countries and areas with adequate data that met the target for suspected cases discarded as nonmeasles per 100,000 population increased from seven (50%) of 14 in 2009 to nine (64%) of 14 in 2012 (Table 3). From 2009 to 2012, suspected cases with adequate investigations increased from 38% to 89%, suspected cases with adequate specimens collected for laboratory testing increased from 79% to 93%, and the proportion of blood specimens received by the laboratory with results available within 7 days increased from 55% to 96% (Table 3).

Measles Disease Incidence and Measles Virus Genotypes

From 2009 to 2012, confirmed measles cases decreased 84%, from 54,291 to 8,524, and confirmed measles incidence per million population decreased 83%, from 34.0 to 5.9 (Table 1). In 2012, the highest confirmed measles incidence was reported from Malaysia (63.7 per million), the Philippines (15.9 per million), and New Zealand (12.3 per million) (Table 1). The highest number of confirmed cases was reported from China and decreased 88%, from 52,461 in 2009 to 6,183 in 2012 (Figure). During 2009–2012, the predominant measles virus genotypes detected in WPR were H1 in China, D9 in the Philippines, Malaysia, and Singapore; and D8 in Malaysia. Other measles virus genotypes that were identified and determined to have been related to measles virus importations from outside WPR included B3, D4, and G3.

Reported by

W. William Schluter, MD, Wang Xiaojun, MD, Jorge Mendoza-Aldana, MD, Youngmee Jee, MD, PhD, Sergey Diorditsa, MD, PhD, Expanded Programme on Immunization, World Health Organization Western Pacific Regional Office, Manila, Philippines. Alya Dabbagh, PhD, Mick Mulders, PhD, Dept of Immunization, Vaccines, and Biologicals, World Health Organization, Geneva, Switzerland. Div of Viral Diseases, National Center for Immunization and Respiratory Diseases; Christopher Gregory, MD, James L. Goodson, MPH, Global Immunization Div, Center for Global Health, CDC. Corresponding contributor: James L. Goodson, jgoodson@cdc.gov, 404-639-8170.

Editorial Note

In 2012, the WPR Regional Committee reaffirmed its commitment to eliminate measles and urged member states to interrupt all residual endemic measles virus transmission as rapidly as possible (6). To achieve elimination, intensified efforts are needed to identify and close gaps in population immunity, by increasing coverage with MCV2 to ≥95% in all countries and areas and by conducting high-quality SIAs in countries with sustained measles virus transmission (e.g., China, Malaysia, and the Philippines). In countries and areas with <95% MCV1 or MCV2 coverage, urgent action is needed to strengthen routine immunization services and to identify and implement targeted SIAs for measles-susceptible populations. In the four remaining countries and areas (Lao People's Democratic Republic, Papua New Guinea, Solomon Islands, and Vanuatu) that do not provide MCV2 in the routine childhood vaccination schedule, strategies are needed to increase MCV1 coverage, conduct periodic SIAs to provide a second opportunity for all birth cohorts to receive MCV, and prepare for introduction of routine MCV2.

The WPR Guidelines on Verification of Measles Elimination (7) were finalized in March 2013; progress toward measles elimination in WPR will be monitored by the Regional Verification Commission through annual progress reports from each country or area and from the Pacific Islands countries and areas reporting as one epidemiologic block. High-quality case-based measles surveillance is critical to the verification process. Despite overall improvement in measles surveillance performance, gaps persist, as reflected by the low proportion of second-level administrative units with one or more nonmeasles discarded case per 100,000 population. Additionally, incomplete investigations of suspected measles cases in some countries challenge efforts to rapidly identify and respond to outbreaks and to measure and document progress toward elimination. For example, in Vietnam, only six (0.8%) of the 771 suspected measles cases with specimens available for testing reported in 2012 were laboratory confirmed. However, 631 additional cases did not have specimens collected but were reported as clinically confirmed measles. The sensitivity of the measles surveillance system in other countries with discarded nonmeasles reporting rates of <2 per 100,000 population might be insufficient to rapidly detect and respond to outbreaks or to meet verification criteria.

The WHO Global Vaccine Action Plan calls for the elimination of rubella and congenital rubella syndrome in five of the six WHO regions by 2020 (8). In April 2012, the Measles and Rubella Initiative launched the 2012–2020 Global Measles and Rubella Strategic Plan to integrate rubella with measles elimination efforts (9). Rubella-containing vaccine is not provided in six WPR countries and areas; five of these countries (Cambodia, Lao People's Democratic Republic, Papua New Guinea, Solomon Islands, and Vietnam) are eligible for financial support offered by the GAVI Alliance to conduct a wide-age-range SIA using combined measles-rubella vaccine followed by the introduction of rubella vaccine in their national routine immunization programs. In addition to contributing to rubella elimination, these SIAs would provide a unique opportunity to boost population immunity to measles and contribute momentum to achieve and sustain measles elimination in WPR.

References

  1. World Health Organization, Regional Committee for the Western Pacific. Resolution WPR/RC56.R8: measles elimination, hepatitis B control, and poliomyelitis eradication. Manila, Philippines: World Health Organization; 2005. Available at http://www2.wpro.who.int/rcm/en/archives/rc56/rc_resolutions/wpr_rc56_r08.htm.
  2. World Health Organization, Regional Office for the Western Pacific. Western Pacific Region measles elimination field guide (2013 version). Manila, Philippines: World Health Organization; 2013 (in press).
  3. World Health Organization. Progress towards the 2012 measles elimination goal in the WHO's Western Pacific Region, 1990–2008, Wkly Epidemiol Rec 2009;84:271–9.
  4. Featherstone DA, Rota PA, Icenogle J, et al. Expansion of the global measles and rubella laboratory network 2005-09. J Infect Dis 2011;204(Suppl 1):S491–8.
  5. World Health Organization. Framework for verifying elimination of measles and rubella. Wkly Epidemiol Rec 2013;88:89–99.
  6. World Health Organization, Regional Committee for the Western Pacific. Resolution WPR/RC63.5: elimination of measles and acceleration of rubella control. Hanoi, Vietnam: World Health Organization; 2012. Available at http://www.wpro.who.int/about/regional_committee/63/resolutions/wpr_rc63_r5_measles_elimination_03oct.pdf.
  7. World Health Organization, Regional Office for the Western Pacific. Western Pacific Region guidelines on verification of measles elimination (2013 version). Manila, Philippines: World Health Organization; 2013 (in press).
  8. World Health Organization. Global vaccine action plan: report by the Secretariat. Geneva, Switzerland: World Health Organization; 2012. Available at http://apps.who.int/gb/ebwha/pdf_files/wha65/a65_22-en.pdf.
  9. World Health Organization. Global measles and rubella strategic plan: 2012–2020. Geneva, Switzerland: World Health Organization; 2012. Available at http://www.who.int/immunization/newsroom/Measles_Rubella_StrategicPlan_2012_2020.pdf.

* Measles elimination is defined as the absence of endemic measles virus transmission in a defined geographic area (e.g., region or country) for ≥12 months in the presence of a well-performing surveillance system.

The Pitcairn Islands, with a population of approximately 50 persons, does not report immunization coverage data to WHO/UNICEF.

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

The epidemiologic block of the Pacific Islands countries and areas includes American Samoa, Cook Islands, Fiji, French Polynesia, Guam, Kiribati, the Marshall Islands, the Federated States of Micronesia, Nauru, New Caledonia, Niue, the Commonwealth of the Northern Mariana Islands, Palau, the Pitcairn Islands, Samoa, Solomon Islands, Tokelau, Tonga, Tuvalu, Vanuatu, and Wallis and Futuna.

** This network includes one WHO global specialized laboratory in Japan, three regional reference laboratories (in Melbourne, Australia; Beijing, China; and Hong Kong, China), 19 national or subnational laboratories, and 31 provincial and 331 prefecture-level laboratories in China.

†† Cases that meet the WHO clinical case definition of measles for which no adequate specimen was collected and cannot be epidemiologically linked to a laboratory-confirmed case of measles.

§§ Essential data elements include name or identifier, date of birth or age, sex, place of residence, vaccination status or date of last vaccination, date of rash onset, date of notification, date of investigation, date of specimen collection, and place of infection or travel history.


What is already known on this topic?

The World Health Organization (WHO) Regional Committee for the Western Pacific Region (WPR) has resolved to eliminate measles by 2012. Substantial progress had been made in reducing the burden from measles by most countries in the region by 2008. The number of reported measles cases in WPR (excluding China) decreased 86%, from 106,172 (255.6 per million population) in 2000 to 14,724 (32.6 per million population) in 2008.

What is added by this report?

This report updates the previous report that summarized progress during 1990–2008 and describes progress toward measles elimination in WPR during 2009–2012. During this period, measles incidence in the region reached a historic low, decreasing by 83%, from 34.0 to 5.9 cases per million population. In China, a nationwide measles vaccination campaign was implemented in 2010 and reported confirmed measles cases decreased 88%, from 52,461 in 2009 to 6,183 in 2012.

What are the implications for public health practice?

Despite the progress to date, achieving measles elimination in WPR will require additional efforts. These include 1) introducing a routine second dose of measles-containing vaccine (MCV) in the four remaining countries and areas that do not yet have a routine 2-dose MCV schedule; 2) strengthening routine immunization services in countries and areas with <95% coverage with the routine first or second dose of MCV; and 3) closing immunity gaps through supplementary immunization activities in measles-susceptible populations in countries and areas that have ongoing measles virus transmission.


TABLE 1. Reported coverage with the first and second dose of measles-containing vaccine (MCV),* age of vaccination, number of confirmed measles cases, and confirmed measles incidence, by country/area — World Health Organization Western Pacific Region, 2009 and 2012

Country/Area

2009

2012

% coverage with
the first
MCV dose

% coverage with
the second
MCV dose

Country or area MCV schedule

No. of confirmed
measles cases

Measles incidence per million population

% coverage with
the first
MCV dose

% coverage with
the second
MCV dose

Country or area
MCV schedule

No. of confirmed
measles cases

Measles incidence per million population

1st dose

2nd dose

1st dose

2nd dose

American Samoa

NR§

NR

M12

Y4

0

0.0

NR

NR

M12

Y4

0

0.0

Australia

94

83

Y1

Y4

104

5.0

94

91

M12

Y4

199

8.7

Brunei Darussalam

100

99

Y1

Y3

2

5.0

99

96

Y1

Y3

1

2.4

CNMI

87

84

M12

Y4

0

0.0

68

65

M12

Y4–6

0

0.0

Cambodia

92

NA

M9–11

NA

865

58.9

93

82

M9

M18

0

0.0

China

99

98

M8

M18–24

52,461

39.5

100

100

M8

M18

6,183

4.6

Cook Islands

78

61

M15

Y4

0

0.0

97

98

M15

Y4

0

0.0

Fiji

72

57

M12

Y6

4

1.3

90

NR

M12

Y6

0

0.0

French Polynesia

99

84

M12

M24

0

0.0

NR

99

M10

M15

0

0.0

Guam

NR

NR

M12

Y4–6

0

0.0

51

44

Y1

Y4–6

0

0.0

Hong Kong (China)

98

99

M12

P1

22

3.1

96**

98

M12

P1

8

1.1

Japan

94

92

Y1

Y5

705

5.5

95

93

Y1

Y5

228

1.8

Kiribati

82

35

Y1

Y6

0

0.0

91

61

M12

P1

0

0.0

Lao People's Democratic Republic

59

NA

M9

NA

72

12.1

72

NA

M9

NA

36

5.6

Macao (China)

91

88

M12

M18

0

0.0

93

89

M12

M18

1

1.8

Malaysia

95

95

Y1††

Y7

56

2.1

86

99

Y1††

Y7

1,868

63.7

Marshall Islands

78

66

M12

M13

0

0.0

78

58

M12

M15

0

0.0

Micronesia

86

82

M12

M13

0

0.0

91

70

M12

M13

0

0.0

Mongolia

94

97

M9

Y2

8

3.0

99

98

M9

Y2

0

0.0

Nauru

100

92

M12

M15

0

0.0

96

81

M12

M15

0

0.0

New Caledonia

99

78

M12

Y2

0

0.0

96

86

M12

Y2

0

0.0

New Zealand

89

NR

M15

Y4

253

60.0

92

85

M15

Y4

55

12.3

Niue

100

100

M15

Y4

0

0.0

100

98

M15

Y4

0

0.0

Palau

75

NR

M12

M15

0

0.0

91

86

M12

M15

0

0.0

Papua New Guinea

58

NA

M9§§

NA

0

0.0

67

NA

M9§§

NA

0

0.0

Philippines

88

58¶¶

M9

M12–15

1,490

16.6

85**

38**

M9

M12–15

1,536

15.9

Republic of Korea

93

100

M12–15

Y4–6

17

0.4

99

97

M12–15

Y4–6

2

0.0

Samoa

49

29

M12

M15

0

0.0

85

67

M12

M15

0

0.0

Singapore

95

93

Y1–2

Y6–7

16

3.6

NR

NR

M12

M15–18

40

7.6

Solomon Islands

60

NA

M12

NA

0

0.0

85

NA

M12

NA

0

0.0

Tokelau

100

100

M12

M15

0

0.0

100

85

M12

M15

0

0.0

Tonga

99

98

M12

M18

0

0.0

95

95

M12

M18

0

0.0

Tuvalu

90

84

M12

M18

0

0.0

98

93

M12

M18

0

0.0

Vanuatu

80

NA

Y1

NA

0

0.0

94

NA

Y1

NA

0

0.0

Vietnam

97

96

M9

Y6

5,222

59.0

96

83

M9

M18

637

7.1

Wallis and Futuna Islands

NR

NR

M9

M18

0

0.0

120

107

M12

M18

0

0.0

Western Pacific Region

96

94

 

 

54,291

34

98

97

 

 

8,524

5.9

Abbreviation: CNMI = Commonwealth of the Northern Mariana Islands.

* Country or area reported coverage for first or second dose of MCV based on administrative data or coverage survey data, if available.

Country MCV schedule abbreviations: M = month of age when dose is given; Y = years of age when dose is given; and P = primary grade of school when dose is given.

§ NR = not reported (country did not report coverage in the year specified).

NA = not applicable (dose was not included in the vaccination schedule for that year).

** Data are preliminary.

†† Additional 6-month dose provided subnationally.

§§ Additional 6-month dose provided nationally.

¶¶ Second dose administered at subnational level; therefore, the denominator is from the population served only.


TABLE 2. Characteristics of measles supplementary immunization activities (SIAs),* by year and country/area — World Health Organization Western Pacific Region, 2009–2012

Year

Country/Area

Age group targeted (mos)

Measles- containing vaccine used

Children reached in targeted age group

Other interventions delivered

Oral polio vaccine

Vitamin A

Deworming medication

Tetanus toxoid vaccination

No.

(%)

2009

China

8–179

M

94,167,415

(98)

 

 

 

 

 

Kiribati

12–59

MR

9,865

(106)

 

Yes

Yes

 

 

Papua New Guinea

6–83

M

945,582

(86)

 

 

 

 

 

Solomon Islands

12–59

M

60,025

(90)

 

 

 

 

 

Vanuatu

12–59

M

29,919

(97)

 

 

 

 

2010

China

8–179

M

102,300,000

(97)

 

 

 

 

 

Federated States of Micronesia

12–83

MMR

11,485

(90)

 

Yes

Yes

 

 

Papua New Guinea

6–35

M

464,973

(83)

Yes

Yes

Yes

 

 

Tuvalu

12–71

MR

1,095

(79)

 

Yes

Yes

 

 

Vietnam

9–71

M

7,034,895

(96)

 

 

 

 

2011

Cambodia

9–119

M

1,819,360

(100)

Yes

Yes

Yes

Yes

 

Lao People's Democratic Republic

9–228

MR

2,614,002

(97)

Yes

Yes

Yes

 

 

Philippines

9–95

MR

15,649,907

(84)

Yes

 

 

Yes

2012

Mongolia

36–179

MR

522,414

(91)

Yes

 

 

 

 

Papua New Guinea

6–35

M

552,872

(88)

Yes

Yes

Yes

Yes

 

Solomon Islands

12–59

MR

68,261

(102)

 

Yes

Yes

 

2009–2012

Western Pacific Region

 

 

226,252,070

(96)

 

 

 

 

Abbreviations: M = measles vaccine; MR = measles and rubella vaccine; MMR = measles, mumps, and rubella vaccine.

* 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 generally 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. The exact age range for follow-up SIAs depends on the age-specific incidence of measles, coverage with measles-containing vaccine through routine services, and the time since the last SIA.

Targeted age groups varied by province.


TABLE 3. Measles surveillance indicators and targets, by country, area, or epidemiologic block* — World Health Organization, Western Pacific Region, 2009 and 2012

Country, area, or
epidemiologic block

2009 

2012

Discarded nonmeasles rate per 100,000

Second-level units with
≥1 discarded cases per
100,000

Suspected cases with adequate investigation

Suspected cases with adequate blood specimens

Laboratory results in ≤7 days of specimen reception

Discarded nonmeasles rate per 100,000

Second-level units with
≥1 discarded cases per
100,000

Suspected cases with adequate investigation

Suspected cases with adequate blood specimens†

Laboratory results in ≤7 days of specimen reception

Target

≥2

≥80%

≥80%

≥80%

≥80%

≥2

≥80%

≥80%

≥80%

≥80%

Australia§

ID

ID

ID

ID

100.0

ID

ID

ID

ID

100.0

Brunei Darussalam

1.5

100.0

75.0

75.0

NA**

1.5

100.0

71.4

85.7

NA

Cambodia

26.4

58.3

62.0

98.4

38.7

6.8

58.3

56.1

99.2

98.3

China

1.3

54.8

86.9

70.1

76.2

2.3

71.0

99.0

97.9

97.1

Hong Kong (China)

0.1

100.0

46.9

71.9

96.2

2.5

100.0

92.0

97.3

98.7

Macao (China)

3.7

100.0

100.0

100.0

98.2

3.9

100.0

95.7

100.0

96.6

Japan

0.0

0.0

ID

ID

ID

0.1

0.0

ID

ID

ID

Lao People's Democratic Republic

2.5

35.3

57.8

60.0

94.0

7.6

64.7

49.3

76.6

93.7

Malaysia

7.9

86.7

34.1

72.4

100.0

22.7

93.8

74.4

83.4

97.7

Mongolia

6.4

47.6

34.5

98.9

100.0

22.0

40.9

64.2

100.0

100.0

New Zealand

ID

ID

ID

ID

99.5

ID

ID

ID

ID

99.3

Papua New Guinea

1.2

15.0

26.8

2.4

NA

0.6

10.0

61.9

81.0

57.6

Philippines

1.6

82.4

29.4

73.8

73.5

2.1

64.7

56.5

79.4

95.3

Republic of Korea

0.1

0.0

40.3

62.7

96.1

0.3

6.3

84.0

90.4

100.0

Singapore

ID

ID

ID

ID

96.4

ID

ID

ID

ID

96.9

Vietnam

4.5

78.1

27.5

72.4

42.5

0.9

25.0

44.3

55.0

96.6

Pacific Islands countries and areas

2.6

13.0

9.9

14.3

100.0

5.7

ID

0.0

ID

93.4

Western Pacific Region

2.8

43.1

38.0

78.8

54.9

2.4

35.1

88.8

93.1

96.0

* The 21 Pacific Islands countries and areas are considered as one epidemiologic block for purposes of measles surveillance.

Excludes epidemiologically linked cases.

§ Reports only confirmed cases.

ID = Insufficient data reported by the country to calculate the indicator.

** NA = not available; no World Health Organization–accredited laboratory in the country.


FIGURE. Confirmed measles cases,* by month of rash onset — World Health Organization Western Pacific Region (WPR), 2009–2012

The figure shows confirmed measles cases, by month of rash onset for the World Health Organization's Western Pacific Region during 2009-2012. The highest number of confirmed cases was reported from China and decreased 88%, from 52,461 in 2009 to 6,183 in 2012.

Abbreviation: SIA = supplementary immunization activity.

* Confirmed measles cases reported by countries and areas to World Health Organization. A case of measles is confirmed by serology when measles-specific immunoglobulin M antibody is detected in a person who was not vaccinated in the previous 30 days. A case of measles is confirmed by epidemiologic linkage when linked in time and place to a laboratory-confirmed measles case but lacks serologic confirmation. During 2009–2012, a case of measles meeting the case definition but without a specimen collected could be reported as clinically confirmed.

SIA conducted in China in which approximately 100 million children aged 8–179 months were vaccinated against measles, with targeted age group varying by province.

Alternate Text: The figure above shows confirmed measles cases, by month of rash onset for the World Health Organization's Western Pacific Region during 2009-2012. The highest number of confirmed cases was reported from China and decreased 88%, from 52,461 in 2009 to 6,183 in 2012.


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