Transcript Slide 1

3rd
June,
2011
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The virus/es
Epidemiology/Statistics
HBV disease complications and Transmission
Risk groups
Prevention, Vaccination
HAV
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HBV
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Hepatitis A and B are inflammatory diseases
of the liver1
Caused by different viruses with different
modes of transmission1,2
Both HAV and HBV provoke liver damage1,3
Both diseases have similar signs and
symptoms1,3
A chronic carrier state may develop
1. WHO, Hepatitis A,
only after hepatitis B2
WHO/CDS/CSR/EDC/2000.7
2. CDC, Hepatitis B, Pink book, 2007
3. WHO, WHO/CS/CSR/LYO/2002.2:
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Despite the differences in their modes of
transmission and clinical outcome, the
geographical distribution of HAV and HBV
are similar
Anti-hepatitis A
virus prevalence
High
Intermediate
Low
1.5 million cases per yr
CDC, Travelers’ health: yellow book, 2007
Hepatitis B surface
antigen (HBsAg)
prevalence
High
Intermediate
Low
Mast, et al. MMWR Recomm Rep 2006; 55 (RR16): 1–25
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Prevalence in General Population – 7-10%
Prevalence in Pregnant Women – 9.3%
(2001 KPA study) and HBeAg - 8.8%
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HBV Markers of Kenyans by early teens – 70%-90%
Prevalence in Blood Donors 5 – 7%
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HBeAg in child bearing age women +ve
for HBsAg –8 - 23.6%
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HBeAg higher in children – 60%
Wankya et al EAMJ 1979
Okoth et al 1990
EAMJ Sept. 2006 KPA study
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Acute infection with jaundice
Acute infection, (can last for long) asymptomatic or
subclinical
Chronic infection
- Chronic Liver Disease
- Liver cirrhosis
- HCC
Symptoms
Antibody titre
HBeAg
anti-HBe
Total anti-HBc
IgM anti-HBc
anti-HBs
HBsAg
0
4
8
12 16 20 24 28 32 36
Weeks after exposure
52
100
CDC, Hepatitis B slide set, 2007
Acute
(6 months)
Chronic
(years)
anti-HBe
HBeAg
HBsAg
Antibody titre
Total anti-HBc
IgM anti-HBc
0
4
8
12 16 20 24 28 32 36
52
Weeks after exposure
CDC, Hepatitis B slide set, 2007
100
80
80
60
Chronic infection
60
40
40
20
20
Symptomatic infection (%)
Chronic infection (%)
100
Symptomatic infection
0
Birth
1–6 months
7–12 months
1–4 years
0
Older children
and adults
Age at infection
CDC, Hepatitis B slide set, 2007
High
Blood
Serum
Wound
exudate
s
Moderate
Semen
Vaginal
fluid
Saliva
Low / not
detectable
Urine
Faeces
Sweat
Tears
Breast milk
CDC, Hepatitis B slide set, 2007
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100-times more infectious than the human
immunodeficiency virus (HIV)
Transmitted by exposure to infected
body fluids (e.g. blood, semen, vaginal secretions):
WHO, WHO/CS/CSR/LYO/2002.2: Hepatitis B
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Horizontal
- Most important than vertical
- Intrafamilial spread important,
(between siblings and btw spouses)
- Intrafamilial more important than school
spread
- high infection rate in infants & children with
highest prevalence reached by age ten (may
be due to higher HBeAg rate)
Greenfield1986 & Wankya 1979)
(Okoth et al 1983 &1990)
(Bowry 1983)
(
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If mother positive for HBsAg and HBeAg
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70%-90% of infants infected
90% of infected infants become chronically
infected
If positive for HBsAg only
5%-20% of infants infected
 90% of infected infants become chronically
infected
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In Asia the rate of HBeAg is highest at
40% hence high PT
 PT is present in Kenya but less common
than horizontal
 Sexual transmission exists but no studies
yet
 Parenteral transmission less
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Hepatitis A
Isolation of
Pathogen
FDA vaccine
Licensure
Efficacy
Hepatitis B
1973
1965
1995
1981
94-100%
80-100%
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NO SPECIFIC ANTIVIRAL TREATMENT
AVAILABLE FOR BOTH
Improved Sanitation and Hygiene
Safe Sex
Screening of pregnant mothers
Vaccination for all, newborns, children,
travellers
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Two types of HBV immunization:
- HBV specific immunoglobulin injection
- Short term protection
- Cab be used at birth to reduce perinatal
transmission in HBsAg + mothers
Active Immunization:
- Current HBV vaccines are based on synthetically
Recombinant HBsA
- Contain sections of HBV protein to stimulate a
natural immune response
- available locally: Euvax B and Engerix B
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Babies born to infected mothers1
Persons living in countries where hepatitis B is endemic1
Family members and sexual contacts of a person infected
with hepatitis B1
Healthcare workers (e.g. surgeons, dentists)1
Institutionalised people (developmentally disabled)2
Public safety workers (e.g. police force, fire service,
prison service)3
Travellers1
People who have multiple sex partners and men who
have sex with men3
Patients on haemodialysis3
Injecting drug users1
1. WHO, WHO/CS/CSR/LYO/2002.2: Hepatitis B
2. Mast, et al. MMWR Recomm Rep 2006; 55 (RR16): 1–25
Patients with chronic liver disease3.4 CDC, Viral hepatitis B fact sheet, 2007
4. Oldfield & Keefe, Rev Gastroenterol Disord 2007; 7: 1–21
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Travellers to areas endemic for both hepatitis A
and B
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People at occupational risk
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Institutionalised individuals
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Sexually active homosexual men
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Patients with chronic liver disease
Van Damme & Van Herck, Expert Rev Vaccines 2004; 3: 249–67
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Hepatitis B is the most important Vaccinepreventable communicable disease
Vaccine:
One of the most widely used vaccine in the world
Safe, used for >25 yrs
95% effective in preventing children and adults from
developing chronic infection
Reports of success in reducing carrier rates in children
generally from 8-15% to <1%
Effective 70-90% in preventing PT given alone within
12 hrs of birth or with Immunoglobulins
Co administration with other vaccines together or
separately
Vaccines: targeting 2000, 2nd WSIPD
Advances in Vaccinology, (1)2007
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Taiwan: seroprevalence decreased from 9.8%
in 1984 to 0.7% in 1999 and incidence
decreased from 0.7:100,000 in 1981/1986 to
0.36:100,000 in 1990-1994 in children.
Chan CY. Et al. Legend of hepatitis B vaccination: Taiwan
experience. J. Gastroenterol. Hepatol. 2004; 19;: 121-126.
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1992 WHO recommendation for universal Hep B
vaccination in all highly endemic (HBsAg carriage
rate>8%)countries by 1995 and all other countries by
1997
Min age of vaccination - birth (monovalent)
Schedules
– 0,1, 6-12 months
- 0,1,2 months for rapid schedule
No need for a booster dose in routine vaccination
SAGE Recommendation:
- In all regions of the world, Perinatal transmission
is responsible for a sizable proportion of CHB
infections. Hence all infants should receive the first
dose of Hep B vaccine as soon as possible after
birth.
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World Health Organization:1
 consider in areas of intermediate endemicity
supplements health education and improved
sanitation
 persons at increased risk of hepatitis A virus
infection should also be vaccinated
Schedule: First dose: 12–23 months:
a booster 6- 12m later
1. WHO, Wkly Epidemiol Rec 2000; 5: 38–44
2. Fiore, et al. MMWR Recomm Rep 2006; 55
(RR07: 1–23
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Mass vaccination has dramatically reduced the
incidence of Hib infections in children under
the age of 5
Vaccine in now used in routine immunization
schedule in more than 100 countries worldwide
Vaccines available in Combination with DPT Pentavalent, Pentaxim, and with HepB Titanrix
www.paho.org/English/HVP/hvp_hib_text.htm
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Options:
I. Birth, 6 wks, 6m
II. Birth, 6wks, 6-9m
III. 6wks, 10w, 6-9m
IV. 6wks, 10wk, 14wk
For HBsAg mothers use the
Birth, 6wk, 6mo schedule (birth dose given
within 4-12hrs)
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Birth
6 Wks
1O Wks
14 Wks
9 Months
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BCG, OPV
OPV, DPT/Hib/HepB
OPV/DPT/Hib/HepB
OPV/DPT/Hib/HepB
Measles, Yellow Fever
Mother & Child Health Booklet MOH
216
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Maragua study, high risk group
Plasma derived HB vaccine – 90.2%
Recombinant HB vaccine – 99.1%
Difference significant
Presently vaccine in u se is Recombinant
Okoth et al 1990
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Senegal - 93% - 95% seroconversion,
- no effect on age, maternal Ab,
pregnancy,
SA, Good seroconversion in babies- 93%
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Im administration not sc
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Booster doses at 5-10 yrs
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Mass hepatitis B Vaccination programmes: Kenya,
Gambia, Cameroon
CKiire Gutt 1996; 38: S5-S12
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The serological response to hepatitis B vaccines is
lower for HIV-infected children and adults than
for uninfected persons of similar age. Serological
response rates have varied, but most studies have
reported that only 25–50% of HIV-infected
children have developed protective antibodies.
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126M – Hep B
20M- Hib
17m – Yellow fever
1.2 B single use syringes distributed for
safe vaccination
http://www.gavialliance.org
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Hepatitis B is a serious disease with serious
complications and Chronicity
Its a major contributing factor to HCC
Has a variable prevalence with high
endemicity in the developing world
It is effectively preventable by the use of
Vaccination