Download The Epidemiology of Hepatitis A, B, and C

Definitions
The Epidemiology of
Hepatitis A, B, and C
Epidemiology:
Jamie Berkes M.D.
University of Illinois at Chicago
[email protected]
Definitions
A microscopic particle that can infect the cells of
biological organisms. Viruses can replicate themselves
only by infecting a host cell. Consist of genetic material
contained within a protective protein coat.
Hepatotropic viruses:
Incidence:
The number of new cases of a disease during a given time interval,
usually one year.
Prevalence:
The total number of cases of a disease in the population at a given
time.
Viral Hepatitis in the US
Virus::
The study of the incidence and prevalence of diseases in large
populations and the detection of the source and cause of epidemics of
infectious disease.
The study of the relationships between exposures such as nutrition,
biological agents, stress, or chemicals to outcomes such as disease,
wellness, and health indicators.
Predominantly infect the liver.
Hepatitis A, B, C, D, and E.
AKA; HAV, HBV, HCV, HDV, and HEV.
Incubation period:
The time between exposure to an infection and when
symptoms and signs first occur.
Acute infections
Acute liver failure
deaths/year
Chronic
infections
Chronic liver
disease
deaths/year
HAV
HBV
HCV
930K
780K
28K
50
100
Rare
0
1-1.25
million
5,000
2.82.8-4 million
0
8,0008,000-10,000
CDC estimates, 2001.
1
REPORTED CASES OF SELECTED NOTIFIABLE
DISEASES PREVENTABLE BY VACCINATION,
UNITED STATES, 2001
Hepatitis A
Hepatitis B
Pertussis
Meningococcal disease
H. influenzae, invasive
Mumps
Measles
Geographic Distribution of Hepatitis A
Virus Infection
10,609
7,843
7,580
2,333
1,597
266
116
Source: NNDSS, CDC
Hepatitis A: Clinical Features
Transmission:
2 to 6 weeks (average 25 days).
Infectivity:
2 to 3 weeks.
> 1 week prior to the onset of symptoms.
Prevalence:
> 40% in U.S. have had previous infection.
~ 100% in developing countries.
Accounts for 40% of all cases of acute viral
hepatitis.
Fecal-oral, unsanitary conditions, contaminated
food/water, rarely blood.
Incubation:
Hepatitis A: Epidemiology
Groups at risk:
Children/workers in day-care
Homosexual men
Residents and traveler in underdeveloped
countries
No risk factor identified for 40%-50% of cases.
2
Hepatitis A: Clinical Course
Symptoms:
Early: fever, nausea and vomiting, fatigue, diarrhea,
anorexia.
Late: right-upper abdominal pain, dark urine, and
jaundice.
Severity/Natural history:
Age dependant.
Jaundice by
age group:
<6 yrs
<10%
6-14 yrs
40%-50%
>14 yrs
70%-80%
Recover is the rule: provides life long immunity from
future infections.
Never causes chronic disease.
Rarely may lead to fulminant liver failure (<1:3000).
45
40
Rate per 100,000
Reported Cases of Hepatitis A, United States,
19521952-2002
35
30
25
20
15
10
5
0
52
Prevention, prevention, prevention.
No effective treatment exists:
Liver transplantation.
Immune globulin, (IG):
For unvaccinated persons, who have recently
been exposed to HAV.
Must be given within two weeks of exposure to
HAV in order to work.
64
68
72
76
80
84
88
92
96 2002
Source: NNDSS, CDC
Hepatitis A: Prevention
Supportive care.
Fulminant Liver Failure:
60
Year
Hepatitis A: Treatment
56
Wash hands after using the bathroom,
changing a diaper, or before preparing or
eating food.
Hepatitis A vaccines:
Provide long-term protection against hepatitis A.
HighHigh-risk persons (IV drug users, homosexual
men, travelers to endemic areas).
Chronic liver disease.
Transplant recipients.
Success rate: >95%.
3
Geographic Distribution of Hepatitis B
Virus Infection
Hepatitis B: Epidemiology
30% of acute viral hepatitis and 15% of chronic viral
hepatitis in the US
Globally
HBsAg Prevalence
United States
≥8% - High
2-7% - Intermediate
<2% - Low
Modes of Transmission
Blood
transfusion
Unknown
Household
contact
Sexual contact
Hemodialysis
Hepatitis B
Occupational
exposure
Injection
drug use
Mother-toinfant
350 million persons infected
75% in Asia
>500,000 deaths per year
1.25 million persons infected (0.3%)
5-15% of Asian Americans
4-5,000 deaths per year
Hepatitis B: Clinical Features
Incubation period:
Average 60-90 days
Range 45-180 days
Clinical illness
(jaundice):
<5 yrs, <10%
>5 yrs, 30%-50%
Acute case-fatality rate:
0.5%-1%
Chronic infection:
<5 yrs, 30%-90%
>5 yrs, 2%-10%
Premature mortality from
chronic liver disease:
15%-25%
4
Clinical Features & Natural
History
95% clear infection and develop lifelong immunity
(HBsAg negative, IgG HBc Ab positive).
5% HBsAg positive for > 6 month = chronic
infection
Hepatitis B Prevention and
Vaccination
Chronicity:
Chronicity: 90% in neonates, 2525-50% of children <6 years
old
Inactive carrier state (low viral level, normal LFT’
LFT’s and
biopsy)
Chronic active hepatitis (elevated LFT’
LFT’s, necrosis and
inflammation on liver biopsy)
Geographic Distribution of Hepatitis
C
Virus Infection
Prevent perinatal HBV transmission
Vaccination is routine for infants
Ages 11-15 “catch up”, and through age 18
Over 18 – high risk groups:
Occupational risk (Health care workers)
Hemodyalisis patients
All STD clinic clients
Multiple sex partners or prior STD
Inmates in Correctional settings
MSM
IDU
Household contacts/sex partners of persons with chronic HBV.
Post-vaccination testing: 1-2 months after last
shot, if establishing response is critical (HCW).
Hepatitis C (HCV)
Hepatitis C is a hepatotropic viral that causes chronic
inflammation of the liver.
Parenteral transmission.
20% of persons infected with HCV develop cirrhosis
over a 40-50 year period.
Acute and chronic infection is typically asymptomatic
until overt liver failure develops (AKA the “silent
killer”)
HCV has replaced alcoholic liver disease as the leading
indication for liver transplantation in the US.
5
Prevalence by Risk Factors
Sexual
contact
Blood
transfusion
prior to 1992
Tattoos, body
piercing
Intranasal
drug use
Organ and
tissue
transplantation
Hepatitis C
Injection
drug use
Percent US population
Modes of Transmission
60
50
58%
40
30
20
3.5%
10
0.7%
0
Noscomial
Occupational
exposure
IDU
Mother-toinfant
Non-IDU
No drugs
Prevalence of HCV
NIH Consensus Development Conference Statement. 2002.
Percent US population
Sexual Transmission
12
Hepatitis C: Clinical Features
Incubation: 2 to 22 weeks
Symptoms
10
8
6
4
2
75% asymptomatic, jaundice uncommon
Fatigue, right upper quadrant abdominal pain
most common symptoms
Chronic infection occurs in 6060-85%
85%
30% have normal liver enzymes
0
0-1
2 to 9
10 to 49
# Lifetime Sexual Partners
> 50
“silent
killer”
killer”
6
NHANES III
(Third National Health and Nutrition
Examination Survey)
HCV seropositivity:
(1.8%)
3.9 million (3.1-4.8)
HCV viremia:
(0.96%)
2.7 million (2.4-3.0)
Highest observed prevalence:
(9.8%)
black men 40 to 49 years old.
Incidence: 28,000 new infections annually
Mortality: 8-10,000 deaths annually
NHANES III 1988 - 1994
4.5
Anti-HCV positive (%)
Age Specific Prevalence
4
3.5
3
2.5
2
1.5
1
0.5
0
6-11
12-19
20-29
30-39
40-49
Alter MJ, et. al. N Engl J Med 1999
Prevalence (%)
6.0
3.4
2.9
3.0
2.0
1.0
2.9
2.4
2.0 1.8
1.6
0.2 0.4
0.7
0.7
0.0
<20
20-29
30-49
>49
Age Group
Alter MJ, et. al. N Engl J Med 1999
P e r c e n t A n ti-H C V P o sitiv e
6.1
4.0
70-79
80+
Prevalence of HCV Infection by
Age, Ethnicity, and Gender, 198819881994
7.0
Caucasian
Mexican
Black
60-69
Alter MJ, et. al. N Engl J Med 1999
HCV Prevalence by Age
& Ethnicity
5.0
50-59
Age (Years)
10
9
8
7
6
5
4
3
2
1
0
Black females
Black males
White males
White females
6-11 12-19 20-29 30-39 40-49 50-59 60-69 70+
Age in Years
Source: NHANES III
7
Estimated Incidence of Acute Hepatitis
C
United States, 19821982-2000
Natural History of HCV Infection
100 People
Surrogate testing of
blood donors
85%
Resolve (15)
Anti-HCV test
(1st generation)
licensed
Chronic (85)
80%
25%
Stable (13)
99
20
00
97
98
96
94
95
92
93
91
89
90
87
88
86
84
85
Mortality (4)
Leading Indication for Liver Transplant
Source: Sentinel Counties
Hepatitis C : Clinical Course
50
Progression Depends on Histologic
Activity
100
40
Percent
Cirrhosis
(17)
75%
Decline among
injection drug users
Decline among
transfusion recipients
20%
Stable (68)
Anti-HCV test
(2ndgeneration)
licensed
82
83
Cases per 100,000
20
18
16
14
12
10
8
6
4
2
0
Time
15%
30
Predictors
Age > 40
> 50 g
ETOH
Male
Fatty liver
HIV
HBV
20
10
0
< 20
30
Cirrhosis
(%)
Severe Inflammation
Moderate Inflammation
50
Mild Inflammation
> 50
Time to Cirrhosis (years)
0
Poynard, Lancet 1997;349:825-832
5
10
Years
15
20
Yano, Hepatology 1996;23:1334-1340
8
Hepatitis C: Indications for
Testing
Transfusion prior to 1992
Hemodialysis
Multiple sexual partners
Spouses/partners
Injection drug use
Intranasal cocaine use
Hepatitis C : Prevention
No vaccine available
Screening and testing donors of blood, organs, and
tissues
RiskRisk-reduction counseling and services
Latex condoms if multiple partners
Avoid sharing toothbrushes, razors, combs
Cover open wounds
Infection control practices
Blood and body fluid precautions
NIH Consensus Statement, 1997
9