(West Africa)

Population (2005) : 3'228'000 % of urban population : 48 Total number of cases (n) : 639 Total number of deaths (n) : 40 Average case - fatality rate (%) : 6 Year of introduction of yellow fever vaccine in routine immunization : 2001

Figure : Yellow fever cases reported in Liberia, 1950-2004

400

370

Yellow fever immunization in routine 350

300

250

200

150

110

100

59

50 42

25 25

5 3 00000000000000000 000000000000000000000000000 0 0 0 0 1950 1952 1954 1956 1958 1960 1962 1964 1966 1968 1970 1972 1974 1976 1978 1980 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004

Table : Yellow fever cases, deaths, case- fatality rate (CFR) and vaccine coverage in Liberia, 1950-2004 Year 1950 1951 1952 1953 1954 1955 1956 1957 1958 1959 1960 1961 1962 1963 1964 1965 1966 1967 1968 1969 Cases (n) 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 5 0 0 Deaths (n) 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 3 0 0 CFR (%) 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 60 0 0 Vaccine coverage (%) 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Year 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 Cases (n) 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Deaths (n) 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 CFR (%) 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Vaccine coverage (%) 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Year 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 Cases (n) 0 0 0 0 0 370 0 3 25 0 110 59 0 25 42 Deaths (n) 0 0 0 0 0 9 0 1 7 0 4 3 0 5 8 CFR (%) 0 0 0 0 0 2 0 33 28 0 4 5 0 20 19 Vaccine coverage (%) 0 0 0 0 0 0 0 0 0 0 0 35 18 7 13

Background :

9 7th in descending order of total number of notified yellow fever cases es in Africa since 1950. 9 Urban outbreak : Buchanan (1995). 9 Complex emergency situation. 9 Rainy season : May - October.

Yellow fever events :

9 July - November 1995 : Buchanan City, . • 359 cases, including 1 death, were officially notified in Buchanan (CFR 0.3%). 55 cases were laboratory confirmed among the 90 samples taken. Laboratory confirmation was obtained 3 weeks after the identification of the first cases. • Yellow fever suspected cases were identified in and in . In the mean time, one yellow fever case was confirmed in . • Aedes aegypti and Aedes africanus were the predominant vectors. • To respond to the outbreak, a mass immunization campaign was launched with a target population of 1,3 million people. In Buchanan, vaccine coverage reached 80% of its 120 000 inhabitants.

9 1995 (continuation) : Margibi, Bong county . • 7 suspected cases of yellow fever , with no death, were identified. • To respond to the outbreak, 180 000 people were vaccinated.

9 1995 (continuation) : Montrovia, . • 4 suspected cases of yellow fever , with no death , were identified. • To respond to the outbreak, 150 00 people were vaccinated.

9 July 1997 : district, . • The outbreak began during the rainy season. Lofa county had not benefited from the mass immunization campaign conducted in 1995 because of civil unrest, poor weather conditions and accessibility. • The index case was laboratory confirmed . He was a 35-year old male and died. The total number of cases is not available. • To respond to the outbreak, mass immunization campaigns were undertaken in Voinjama (94% vaccine coverage) and in the neighboring districts of Bolahun, Kolahun and , with a vaccine coverage ranging from 39% to 43%. The target population included the numerous refugees repatriated from . Liberian refugees displaced in Côte d'Ivoire were vaccinated thanks to the Ivorian government's collaboration. The mass immunization campaign experienced the same logistics difficulties than in 1995.

9 June 1998 : Duowin surroundings, . • Most of the cases occurred among a single family and their relatives. They lived in a forested farm, located at 3 hours walking distance from Duowin. • 25 cases, including 7 deaths, were officially notified (CFR 28%). 4 cases were laboratory confirmed . 68% of the cases were over 20 years of age. The M/F sex ratio was 0.9. • To respond to the outbreak, 180 000 people were vaccinated in August.

9 August - September 2000 : . • 102 cases were officially notified.

9 August 2001 : Mariland county. • 3 yellow fever cases , including 3 deaths , were officially notified (CFR 100%). 1 case was laboratory confirmed . • To respond to the outbreak, a mass immunization campaign was planned in the affected county.

9 January - March 2003 : Salala district, Bong county. • 10 yellow fever cases, including 3 deaths, were officially notified (CFR 30%). 2 cases were laboratory confirmed . • To respond to the outbreak, 26 498 people were vaccinated. Vaccine doses came from the global yellow fever vaccine stockpile supported by GAVI.

9 March 2003 : Gbelageh and Zoe-Geh districts, Nimba county. • 10 cases, including 2 deaths, were officially notified (CFR 20%) in Gbelageh. 2 cases were laboratory confirmed. • To respond to the outbreak, 49 473 people were vaccinated in Gbelageh and 23 680 in Zoe-Geh. Vaccine doses came from the global yellow fever vaccine stockpile supported by GAVI. • 9 January - March 2004: Bong, Gbarpolu, Grand Bassa, Grand Gedeh, Margibi, Montserrado, Nimba and River Gee counties. • 8 of the 15 counties of the country were affected by the epidemic. • 42 cases, including 8 deaths, were officially notified (CFR 19%). 4 cases, all of them from Bong and Nimba counties, were laboratory confirmed. Laboratory confirmation was obtained in 2 weeks. • To respond to the outbreak, a mass immunization campaign was carried out in the Bong and Nimba counties, bordering respectively Guinea and Côte d’Ivoire. 49 395 people were vaccinated in the refugee camps of Totota and Miamu I, II, III (Bong) and 32 318 people in the Western part of Zoe-geh (Nimba). Vaccine doses came from the global yellow fever vaccine stockpile supported by GAVI. Yellow fever cases reported in Liberia, 1950- 2004

Voinjama 1995

Guinea Sierra Leone

Sanniqueville 1998 2000 2003

Bopolu 2004

Tubmannburg

Robertsport 2003 2004 2004 Côte d'Ivoire

Buchanan 1995 2004 Atlantic Ocean

River Cess Fish Town

1995 No reported case 2004 Barclayville 1 case

≥ 2 cases 2001

Administrative level 1 boundary Harper Main road

The boundaries and names shown and the designations used on this map do not imply the expression of any opinion whatsoever on the part of the World Health Organization concerning the legal status of any country, territory, city or area or of its authorities, or concerning the delimitation of its frontiers or boundaries. Dotted lines on maps represent approximate border lines for which there may not yet be full agreement. © WHO 2005. All rights reserved.

Bibliography:

1. The yellow fever situation in Africa and South America in 2004. Wkly Epidemiol Rec. 2005 July 22;80(29):250-56. 2. Yellow fever, 1998-1999. Wkly Epidemiol Rec. 2000 Oct 06;75(40):322-28. 3. Yellow fever, 1996- 1997. Part I. Wkly Epidemiol Rec. 1998 Nov 13;73(46):354-59. 4. Yellow fever in Liberia. Wkly Epidemiol Rec. 1997 Aug 15;72(33):252. 5. Yellow fever in 1994 and 1995. Wkly Epidemiol Rec. 1996 Oct 18;71(42):313-18. 6. Yellow fever in Liberia. Wkly Epidemiol Rec. 1995 Dec 15;70(50):360. 7. Yellow fever in Liberia. Wkly Epidemiol Rec. 1995 Nov 17;70(46):332.

Last updated : 21 September 2005