Epidemiology of Viral Hepatitis

Ashry Gad Mohamed

Prof. of Epidemiology

Consultant Medical Epidemiologist

Hepatitis A

• Abrupt onset.

• Fever

• Malaise

• Anorexia

• Abdominal discomfort

• Jaundice

• More than 90% are asymptomatic

• Seroprevalence increases with age.

• At age 15, 95% are seropositive.

• Case fatality rate (CFR)= 0.3%.

• If age > 40 years CFR=2%.

• Studies in KSA:

1997 25%

1999 25% Taif

10-82% Jazan (1-12 years)

• Agent: RNA virus

• Reservior : Human (Clinical & subclinical

cases)

• Incubation period: 15-35 days ( median

one month).

• Period of communicability : Last two weeks of I.P. + one week of illness.

• Modes of transmission:

Fecal-oral route.

Common source outbreaks.

Blood transfusion (rare).

Prevention and Control

• Good sanitation & personal hygiene. “Careful hand washing”• Day- Care centers Hand washing after every diaper change and before eating.• Shellfish heat 85-90C 4 minutes. steam 90 seconds.

• Inactivated hepatitis A vaccine

0 -1 -6 months.

Protection after one month.

Lasting immunity at least 10 years.

• Hepatitis A patient:

Enteric precaution for the PC

Hepatitis B

• Incidous onset.

• Anorexia.

• Abdominal discomfort.

• Nausia.

• Vomiting.

• Arthralgia.

• Jaundice.

• Carriage rates: Sudan 13-19% Pakistan 10-16% Egypt 2.7-15% Saudi Arabia 8.5% Jordan 7-10. Syria 4-6% Iraq 4-5% Morocco 3-6% Yemen 5-6%

2 billion people infected 360 million CHB

More than 500,000 death/year

OVERALL PREVALENCE OF HBsAg AMONG SAUDIS IN THE 80’S ACCORDING TO REGIONS

5.5

8.99.6

8.3

0

2

4

6

8

10

Central(n=6649)

South-western(n=7235)

Eastern(n=8300)

Total (n=32183)

Pos

itiv

ity

(%)

Al-Faleh. Annals of Saudi Medicine, 1988

COMPARISON OF PREVALENCE OF HBsAg AMONG SAUDI CHILDREN IN 1989 (n=4575) AND 1997 (n=5355) – ACCORDING TO

AGE

9.68

0 0

6.54

0.16

7.24

0.3

5.06

0

6.35

0

7.57

0.2

6.51

0.82

7.2

0.93

5.81

2.31

0

66.71

0.310

2

4

6

8

10

Per

cent

age

1 2 3 4 5 6 7 8 9 10 11 12

Tot

al

(Age in years)

1989 1997Al Faleh, J Infect 1999

PREVALENCE OF HBsAg POSITIVITY AMONG BLOOD DONORS IN KKUH FROM 1987 TO 2000

4.7

3

1.4

1.971.7

1.21.7

0

1

2

3

4

5

1987 (n= 3565)

1991(n=1991)

1996(n=6885)

1997(n=6285)

1998(n=6031)

1999(n=6841)

2000(n=6394)

Pos

itiv

ity

(%)

Natural History

Gow, BMJ 2001

• Agent: Double strand DNA.

Serotypes adw, ayw, adr, ayr.

• Reservior: Human (case + carrier).

• I.P. 2-3 months.

• P.C. One week of I.P. + illness period + carriage.

• Carriage depends on age.

Concentration of Hepatitis B Virus in Various Body Fluids

Concentration of Hepatitis B Virus in Various Body Fluids

High ModerateLow/Not

Detectable

blood semen urineserum vaginal fluid feces

wound exudates saliva sweat

tearsbreastmilk

• Sexual

• Parenteral

• Perinatal

Hepatitis B Virus Modes of Transmission

Hepatitis B Virus Modes of Transmission

Modes of transmission:

• Percutaneous and permucosal exposure to infective body fluids.

Blood transfusion.

Organs transplants.

Sharing needles.

Haemodialysis.

Needlestick.

Tattooing.

Razors & toothbrushes.

• Sexual transmission.

• Perinatal transmission.

Prevention and control

• Wide scale immunization of infants.• Immunization of high risk persons. Haemodialysis patients. Bleeding disorders. Susceptible households. Health care personnels.• Blood banks: avoid donors from risky groups.

Education & history taking.

Testing for HBs Ag.

• Discourage:

Tattooing, Drug abuse,

Extramarital sexual relations.

• Needle stick

Single dose of HBIG (24 hours).

Vaccine series.

• Sexual exposure

Single dose of HBIG (14 days).

Vaccination.

• Infants to HBsAg +ve mothers.

0.5 ml HBIG im.

First dose of the vaccine.

2nd & 3rd doses at 1 & 6 months later.

• Health care personnel.

Universal precautions

Hepatitis C

USA 4 M

USA 4 M

SOUTH

AMERICA

10 M

SOUTH

AMERICA

10 M

AFRICA 32 MAFRICA 32 M

EASTERNMEDITERRANEAN

20M

EASTERNMEDITERRANEAN

20MSOUTH EAST

ASIA30 M

SOUTH EAST ASIA30 M

AUSTRALIA0.2 M

AUSTRALIA0.2 M

WHO, 1999

WESTERN EUROPE

9 M

WESTERN EUROPE

9 M

FAR EAST/ASIA60 M

FAR EAST/ASIA60 M

170 Million Hepatitis C virus (HCV) carriers

3-4 MM new cases / year

170 Million Hepatitis C virus (HCV) carriers

3-4 MM new cases / year

AGE SPECIFIC PREVALENCE OF ANTIBODY TO HCV/ANTI-HCV AMONG HEALTHY SAUDIS

Age Group

(years)

Community Based Study

No. tested Anti-HCV Pos. (%)

Location

1 – 10 1214

490

677

1096

1019

0.6

0.0

0.4

0.9

1,9

Central Province

Eastern Province

North-Western Province

South-Western Province

Southern Province

10 – 19 504 6 (1.2) Gizan

20 – 29 361 4 (1.1) Gizan

30 - 39 290 6 (2.1) Gizan

40 – 49 183 6 (3.3) Gizan

> 50 144 5 (3.5) Gizan

Total 1482 27 (1.8) Gizan

Al-Faleh et al, Hepatology Vol. 14(2), 1991

COMPARISON OF PREVALENCE OF ANTI-HCV IN SAUDI CHILDREN BETWEEN THE STUDIES

CARRIED OUT IN 1989 AND 1997

0.87

0.04

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

Per

cent

1989 (n=4496) 1997 (n=5350)

PREVALENCE OF ANTIBODY TO HCV TO SAUDI HIGH RISK GROUPS

High Risk Group No. Tested

No. Pos.

% Location

Hemophiliacs 28 22 78.6 KKUH, Riyadh

Thalassaemia and sickle cell disease

78 26 33.3 KKUH, Riyadh

-thalassaemia major

20 14 70.0 KKUH, Riyadh*

Sickle cell anaemia 55 10 18.2 KKUH, Riyadh*

Patients with sexually transmitted diseases

220 35 15.9 KKUH, Riyadh*

2nd-generation anti-HCV tests and confirmation were only donein this study.

ANTI-HCV IN HAEMODYLYSIS PATIENTS IN SAUDI POPULATION

Author No. of Persons Type of Test %

Fakunle et al 895 ELISA I 53.7

Al-Mugeriren et al 20 Children ELISA I 45.0

Ayoola et al 74 ELISA I 41.9

Huraib et al 22 HD Centre

1147 Persons

ELISA II 68.8

• 11( 6 major) with many subtypes and quasispecies

• The predominate genotype in Saudi is Genotype 4 (62.9% )

• Europe & America Genotype 1 75 (24.8) % severe disease

• Genotype 2 = 10.8 (7.4) %

• Genotype 3 = 5.8 (5.9) %

• Genotype 1 & 4 Poor response to therapy

Hepatitis C Virus Genotypes

Natural History of HCV Infection

Exposure(Acute phase)

ResolvedResolved Chronic

CirrhosisStableStable

SlowlySlowlyProgressiveProgressive

HCCTransplant

Death

20% (17)

15% (15) 85% (85)

25% (4)

80% (68)

75% (13)

HIV and HIV and AlcoholAlcohol

MJ Semin Liver Dis 1995; 15: Management of Hepatitis C NIH Consensus Statement 1997; March 24-26:15(3).

Blood transfusio

n

Blood transfusio

nIV drug abuseIV drug abuse

Important HCV Transmission Modes

Important HCV Transmission Modes

1:100,000 in US80% infected in first year

Vertical transmission mother - Child

Vertical transmission mother - Child

Uncommon HCV Transmission Modes

Uncommon HCV Transmission Modes

Household transmission

1-5%

?

Needle stick injury

3%

Other Transmission Issues

HCV not spread by kissing, hugging, sneezing, coughing, food or water, sharing eating utensils or drinking glasses, or casual contact

Do not exclude from work, school, play, child-care or other settings based on HCV infection status

HCV Counseling

Features of Hepatitis C Virus InfectionFeatures of Hepatitis C Virus Infection

Incubation periodIncubation periodAverage 6-7 weeksAverage 6-7 weeks Range 2-26 weeksRange 2-26 weeks

Acute illness (jaundice)Acute illness (jaundice) Mild (Mild (<<20%)20%)

Case fatality rateCase fatality rate LowLow

Chronic infectionChronic infection 60%-85%60%-85%

Chronic hepatitisChronic hepatitis 10%-70%10%-70%

CirrhosisCirrhosis <5%-20%<5%-20%

Mortality from CLDMortality from CLD 1%-5%1%-5%

Age-related

Chronic Hepatitis C Factors Promoting Progression or Severity

• Increased alcohol intake

• Age > 40 years at time of infection

• HIV co-infection

• Other– Male gender– Chronic HBV co-infection

Serologic Pattern of Acute HCV Infection with Progression to Chronic Infection

Symptoms +/-

Time after Exposure

Tit

eranti-HCV

ALT

Normal

0 1 2 3 4 5 6 1 2 3 4YearsMonths

HCV RNA

Exposures Known to Be Associated With

HCV Infection in the United States

• Injecting drug use• Transfusion, transplant from infected donor • Occupational exposure to blood

– Mostly needle sticks

• Iatrogenic (unsafe injections)• Birth to HCV-infected mother• Sex with infected partner

– Multiple sex partners

Injecting Drug Use and HCV Transmission

• Highly efficient– Contamination of drug paraphernalia, not just

needles and syringes

• Rapidly acquired after initiation– 30% prevalence after 3 years– >50% after 5 years

• Four times more common than HIV

Occupational Transmission of HCV

• Average incidence 1.8% following needle stick from HCV-positive source – Associated with hollow-bore needles

• Prevalence 1-2% among health care workers – Lower than adults in the general population– 10 times lower than for HBV infection

HCV Related to Health Care Procedures

• Recognized primarily in context of outbreaks– Chronic hemodialysis– Hospital inpatient setting– Private practice setting– Home therapy

• Unsafe injection practices– Reuse of syringes and needles– Contaminated multiple dose medication vials

HCW to Patient Transmission of HCV

• Rare– In U.S., none related to performing invasive

procedures

• Most appear related to HCW substance abuse– Reuse of needles or sharing narcotics used for

self-injection

• No restrictions routinely recommended for HCV-infected HCWs

Perinatal Transmission of HCV

• Transmission only from women HCV-RNA positive at delivery– Average rate of infection 6%– Higher (17%) if woman co-infected with HIV– Role of viral titer unclear

• No association with– Delivery method– Breastfeeding

• Infected infants do well– Severe hepatitis is rare

Sexual Transmission of HCV

• Case-control, cross sectional studies– Infected partner, multiple partners, early sex, non-

use of condoms, other STDs, sex with trauma, Partner studies

– Low prevalence (1.5%) among long-term partners• infections might be due to common percutaneous

exposures (e.g., drug use), BUT

– Male to female transmission more efficient• more indicative of sexual transmission

Household Transmission of HCV

• Rare but not absent• Could occur through percutaneous/mucosal

exposures to blood– Contaminated equipment used for home

therapies• IV therapy, injections

– Theoretically through sharing of contaminated personal articles (razors, toothbrushes)

Reduce or Eliminate Risks for Acquiring HCV Infection

• Screen and test donors• Virus inactivation of plasma-derived products• Risk-reduction counseling and services

– Obtain history of high-risk drug and sex behaviors

– Provide information on minimizing risky behavior, including referral to other services

– Vaccinate against hepatitis A and/or hepatitis B• Safe injection and infection control practices

Reduce Risks for Disease Progressionand Further Transmission

• Identify persons at risk for HCV and test to determine infection status– Routinely identify at risk persons

through history, record review

• Provide HCV-positive persons– Medical evaluation and management– Counseling

• Prevent further liver damage• Prevent transmission to others

MMWR 1998;47 (No. RR-19)

HCV Prevalence by Selected GroupsUnited States

0 10 20 30 40 50 60 70 80 90

Hemophilia

Injecting drug users

Surgeons, PSWs

Hemodialysis

Average Percent Anti-HCV Positive

Gen population adults

Military personnel

STD clients

Pregnant women

HCV Testing Routinely Recommended

• Ever injected illegal drugs• Received clotting factors made before 1987• Received blood/organs before July 1992 • Ever on chronic hemodialysis• Evidence of liver disease

• Healthcare, emergency, public safety workers after needle stick/mucosal exposures to HCV-positive blood

• Children born to HCV-positive women

Based on increased risk for infection

Based on need for exposure management

Postexposure Management for HCV

• IG, antivirals not recommended for prophylaxis

• Follow-up after needlesticks, sharps, or mucosal exposures to HCV-positive blood– Test source for anti-HCV – Test worker if source anti-HCV positive

• Anti-HCV and ALT at baseline and 4-6 months later

• For earlier diagnosis, HCV RNA at 4-6 weeks– Confirm all anti-HCV results with RIBA

• Refer infected worker to specialist for medical evaluation and management

Hepatitis E - Clinical

FeaturesHepatitis E - Clinical

Features

• Incubation period: Average 40 daysRange 15-60 days

• Case-fatality rate: Overall, 1%-3%Pregnant women,

15%-25%

• Illness severity: Increased with age

• Chronic sequelae: None identified

•Most outbreaks associated withfecally contaminated drinking water

•Minimal person-to-person transmission

Hepatitis E -

Epidemiologic FeaturesHepatitis E -

Epidemiologic Features

Geographic Distribution of Hepatitis E

Geographic Distribution of Hepatitis EOutbreaks or Confirmed Infection in >25% of Sporadic Non-ABC Hepatitis

Outbreaks or Confirmed Infection in >25% of Sporadic Non-ABC Hepatitis

Viral Hepatitis - OverviewViral Hepatitis - Overview

AA BB CC DD EESource ofvirus

feces blood/blood-derived

body fluids

blood/blood-derived

body fluids

blood/blood-derived

body fluids

feces

Route oftransmission

fecal-oral percutaneouspermucosal

percutaneouspermucosal

percutaneouspermucosal

fecal-oral

Chronicinfection

no yes yes yes no

Prevention pre/post-exposure

immunization

pre/post-exposure

immunization

blood donorscreening;

risk behaviormodification

pre/post-exposure

immunization;risk behaviormodification

ensure safedrinkingwater

Type of HepatitisType of Hepatitis