HEPATITIS A

Last updated: 06 September 2004

1. Reason for surveillance

• To identify the source of the infection and to prevent further cases
• To monitor the epidemiology of hepatitis A and so inform the development of better prevention strategies.

2. Case definition

Probable case
A probable case requires clinical AND epidemiological evidence.

Laboratory evidence
Not applicable.

Clinical evidence
Clinical hepatitis (jaundice and/or bilirubin in urine) without a non-infectious cause.

Epidemiological evidence
Contact between two people including a plausible mode of transmission at a time when:

• One of them is likely to be infectious (from two weeks before onset of jaundice to a week after onset of jaundice), and
• The other has an illness that starts within 15 to 50 (average 28-30) days after this contact, and
• At least one case in the chain of epidemiologically linked cases (which may involve many cases) is laboratory confirmed.

Confirmed case
A confirmed case requires laboratory definitive evidence only.

Laboratory definitive evidence

• Detection of anti-hepatitis A IgM, in the absence of recent vaccination, or
• Detection of hepatitis A virus by nucleic acid testing.

Clinical evidence
Not applicable.

Epidemiological evidence
Not applicable.

Factors to be considered in case identification
The illness is frequently mild, though prolonged and severe cases can occur. Subclinical and anicteric infections can occur, and are frequent in children <5 years old. Hence it is important to obtain a laboratory diagnosis wherever possible.

In a patient who has not recently been vaccinated for hepatitis A, diagnosis is established by the presence of IgM anti-HAV antibodies. IgM antibodies usually become detectable before the onset of clinical symptoms and persist for ≥4 months in most persons (and occasionally up to 1 year). Approximately three percent of HAV infected people will be IgM negative if blood is taken on or before the onset of jaundice. Probable cases with negative IgM results from early specimens should be retested in 4 to 7 days. IgM antibodies are detectable in subclinically infected persons as well as symptomatic cases.

Anti-HAV IgG antibodies are markers of any exposure to the disease or immunisation and they persist for life after infection. Although useful for identifying persons who are currently immune to HAV infection, they are not useful indicators of recent infection.

3. Notification criteria and procedure

Hepatitis A is to be notified by:

• Medical practitioners and hospital CEOs on diagnosis of acute viral hepatitis (ideal reporting by telephone on same day of diagnosis)
• Laboratories on serological confirmation (ideal reporting by telephone on same day of diagnosis).

Probable and confirmed cases should be entered onto NDD.

4. The disease

Infectious agents
The hepatitis A virus (HAV), an RNA picornavirus.

Mode of transmission
Hepatitis A is transmitted almost entirely by the faecaloral route. It may occur through contamination of food by poor food handling practices, faecal contamination of drinking water, ingestion of filter-feeding shellfish raised in contaminated waters and ingestion of faecal material transferred by direct contact including sexual contact.

In recent years, outbreaks of hepatitis A have been identified in NSW linked to contaminated oysters, childcare centres, infectious food handlers, gay men, and injecting drug users and homeless youth.

Parenteral transmission is rare because viraemia is brief and the concentration of virus in blood is low. Urine may be infective during this brief period of viraemia. Saliva has not been shown to be a source of infection.

The virus can remain infectious for ≥ 1 month at room temperature on environmental surfaces, so transfer on fomites is likely to be important in some settings, such as in child care facilities.

Timeline
The incubation period is 15 to 50 days, but more commonly 28 to 30 days.

Maximum infectivity occurs during the latter half of the incubation period, extending to a few days after onset. The concentration of virus in the stool, and therefore the infectivity, is highest before onset of symptoms. Cases can generally be considered non-infectious a week after onset of jaundice (if it occurs) or 2 weeks after onset of prodromal symptoms, whichever comes first. (This period may be longer in immunocompromised persons.)

Clinical manifestations
The usual clinical presentation is acute fever, malaise, anorexia, nausea and abdominal discomfort followed a few days later by dark urine and jaundice. Symptoms usually last several weeks. The likelihood that symptoms will follow infection increases with age: jaundice occurs in only a small proportion of infants and young children, but a majority of adults.

5. Managing single notifications

Response times
Investigation
Within 1 working day of notification of a probable or confirmed case begin follow-up investigation.

Data entry
Within 1 working day of notification enter probable and confirmed cases on NDD.

Response procedure
The response to a notification will normally be carried out in collaboration with the case's health carers. But regardless of who does the follow-up, PHU staff should ensure that action has been taken to:

• Confirm the onset date and symptoms of the illness
• Confirm results of relevant pathology tests, or recommend the tests be done
• Find out if the case or relevant care-giver has been told what the diagnosis is before beginning the interview
• Seek the doctor's permission to contact the case or relevant care-giver
• Review case and contact management, ensuring that relevant exclusions have been made
• Determine the likely source of infection
• Assess the number of contacts requiring NIGH
• Ensure proper control measures are taken to prevent further spread.

Case management
Investigation and Treatment
Treatment is supportive only.

Education
The case or relevant care-giver should be informed about the nature of the infection and the mode of transmission. Education should include information about hygienic practices, particularly hand-washing before preparing food and eating and after going to the toilet.

Adult cases should also be advised, during the infectious period:

• Not to donate blood
• Not to prepare or handle food to be consumed by other people
• Not to practise oral or anal sex
• Not to share drug paraphernalia, and
• To advise health care workers of infection.

Exposure investigation
Information regarding exposures during the period 15 to 50 days before onset of jaundice should be sought. This should include information about:

• Household and sexual contacts who have had an illness consistent with hepatitis
• Restaurants where the case has eaten
• Social gatherings where the case has eaten
• All sources of drinking water
• Consumption of raw or partially cooked shellfish
• Attendance or employment at child care centres by case or household contacts
• Illicit drug use
• Travel by the case or household contacts to countries with endemic hepatitis A
• Recreational water exposure
• Exposure to sewage, or failed sewage disposal systems.

Isolation and restriction
Confirmed and probable cases should not attend child care facilities during the infectious period. Cases must not provide personal care to people in child care or health care settings or handle food for others while infectious(for at least 7 days after onset of jaundice or dark urine, or 2 weeks after onset of the prodrome).

Environmental evaluation
Water supply
Drinking water systems are potential sources of HAV infection if there is opportunity for faecal contamination. Where an unexpected cluster is reported, an evaluation may include review of water treatment procedures and bacteriological quality.

Sewage disposal
Determine if the case has been exposed to a failed sewage disposal system.

Food service facility
Where contaminated food is a suspected source, PHU staff should ask the NSW Food Authority Foodborne Outbreak Coordinator to ensure that the premises where food was prepared is evaluated to determine the likelihood of disease transmission (see section 6).

Childcare facility
PHU staff should review the facility's infection control procedures to determine the likelihood of disease transmission, and establish if carers of children <2 years old have changed nappies and prepared food in the same shift (see section 6).

Contact management
Identification of contacts
The following is a general list of persons considered to be contacts if exposed to infectious cases:

• All immediate family, household members and sexual partners
• All persons who consumed food not subjected to further cooking that was prepared by the case (see section 6)
• If case is a food handler, other food handlers in the same establishment
• All persons who provided direct care to cases who are in nappies.

In child care centres and preschools with separate sessions, only the affected group need be regarded as at increased risk. However, written advice may be offered to parents and staff caring for children in other groups (see section 6).

Investigation and treatment
Passive immunisation
Normal immunoglobulin (human) (NIGH, also called gamma globulin) is a preparation of pooled antibodies which, given soon after exposure, will prevent or modify clinical illness. Its efficacy declines rapidly within days of exposure, and becomes ineffective about 2 weeks after exposure. NIGH should be given in a single intramuscular dose at the following dosage:

The routine administration of NIGH to contacts of a case of hepatitis A in the school or workplace is not usually necessary, but may be recommended in certain cases. NIGH is rarely given to persons exposed to a potential common source of HAV (such as food or water) because cases related to such a source are usually recognised too long after the exposure for NIGH to be effective.

NIGH is available through the Australian Red Cross Blood Service (ARCBS) during working hours by calling the Transfusion Medical Officer on 9229-4347, or the After Hours Medical Officer on call 9229 4444. ARCBS keeps a small stock of NIGH at its Clarence Street, Sydney and Newcastle Distribution Departments. These departments are not set up for public access. The majority of NIGH is issued via CSL at North Ryde following approval from ARCBS.

For individual doses, the ARCBS may provide NIGH from stock at a local hospital, issue stock direct or access it via CSL, depending on the urgency.

For outbreaks, the PHU should discuss with ARCBS the number of potential patients involved and the best way to distribute the product according to whether a clinic will be set up or whether patients will be referred to individual GPs. The Communicable Diseases Branch can assist in negotiations. If a clinic is planned, ARCBS will arrange for product to be transported to the site of clinic, but the PHU will need to ensure availability of suitable storage for the NIGH (e.g., the hospital blood bank or pharmacy). If it is planned to refer patients to individual GPs, a suitable entral access point for NIGH will need to be identified (e.g., a local hospital blood bank or pharmacy). The PHU is responsible for notifying GPs on the process for accessing product for their patients.

Small stocks of NIGH are held at some hospitals including: Westmead, Wollongong, Gosford, John Hunter, Cessnock, Albury, Orange, Macksville, Port Macquarie, Lismore, Tamworth, Armidale, Narrabri, Wagga Wagga, Tumut, Griffith, Broken Hill, Hornsby and Sutherland.

Active immunisation
A single dose of hepatitis A vaccine gives protection to most recipients within 2 weeks. It may be given at the same time as NIGH, when both immediate and long-term protection is required. There is currently insufficient evidence to support the routine use of HAV vaccine as post-exposure prophylaxis. However if a contact wishes to receive vaccine rather than NIGH, then the cost should be borne by the contact, rather than by NSW Health.

Recent immunisation may confuse the interpretation of follow-up serology.

Antibiotic prophylaxis
None

Education
Provide contacts (or parents/guardians) with a Hepatitis A Fact Sheet, including advice on the risk of infection; counsel them to watch for signs or symptoms of hepatitis occurring within 50 days of exposure and seek medical attention early if symptoms develop. Parents of infants or young children should be reminded that jaundice may not occur. Advice about careful hygiene should be given, particularly about hand washing after going to the toilet.

It is especially important that any food handlers monitor their own development of hepatitis symptoms after contact with the disease and seek medical attention promptly if symptoms are detected.

Isolation and restriction
Contacts are not normally excluded from child-care, school or work.

6 Managing Special Situations

Cases among children or staff in child care
Because most HAV infections in young children are asymptomatic, illness among staff members or household contacts is often the first (and only) indication of daycare facility outbreaks.

Case attends or works at a child-care centre that serves children in nappies
If recent or ongoing transmission is suspected within the childcare centre, NIGH prophylaxis is generally recommended for staff and attendees in the affected class. If >1 case is associated with the centre, NIGH may be indicated for all household contacts of attendees.

In order to quickly identify new infections, the PHU should institute surveillance for hepatitis-like illness among households connected to the centre for 50 days after onset of the last case; this is usually done by letter. All such households should be provided with basic information about hepatitis A, and instructed to contact the PHU immediately should suspicious symptoms develop.

The critical role of good personal hygiene (especially handwashing) should be reviewed with child-care staff. Staff involved in food handling should not be involved in changing nappies on the same shift.

Affected centres should be discouraged from accepting new children for 50 days after onset of the last case, unless NIGH or vaccine is given before admission. Transferring children to other centres should be discouraged during this period.

Case is a household contact of a child-care attendee
It is helpful to test any child-care attendees in such households for IgM anti-HAV, in order to rule out asymptomatic infections. If positive, see previous section. Interview the child care operator to identify any suspect cases among staff or attendees, and review relevant operations at the centre. Institute surveillance for suspect cases among staff and attendees for a period of 50 days from the onset of the last case. Two or more cases reported from different households linked to the same centre suggests child-care-associated transmission, and should be investigated as such.

Cases among infectious food handlers
PHU staff must work in close collaboration with the NSW Food Authority Foodborne Outbreak Coordinator in managing the risk to other staff and patrons.

Risk to other food handlers
Food handlers can transmit hepatitis A to consumers through contaminated food. If the investigation shows that other food handlers at the facility are at risk because they either ate food prepared by the case, or because they shared toilets or washing facilities with the case, then NIGH should be provided to other unimmunised food handlers at the facility.

Where other cases are suspected among food handlers, blood should be collected (with consent) for serology.

Alerting patrons when a risk is identified
It can be difficult to identify all people who may have been exposed to food prepared by a case. It is therefore important to evaluate the degree of risk to patrons by assessing the risk behaviours of the case.

Where a risk is identified, there are two primary reasons to alert patrons:

• To provide NIGH to potentially exposed individuals, in order to prevent further cases
• To warn persons (and their doctors) who may be already incubating the infections about their exposure, educating them about the symptoms and signs of hepatitis, in order to facilitate rapid diagnosis and prevent a subsequent generation of cases. (Public announcements can be worthwhile even if it is too late to offer NIGH to exposed individuals.)

These measures can be readily applied in a setting with an easily located clientele, such as a school, childcare centre or private home. Identification and follow-up of consumers is not as easy in other food service settings such as restaurants and sandwich shops. In these situations, it sometimes becomes necessary to notify those at risk through the news media or other forms of public announcement. The food service facility operators should be counselled about their responsibility to protect the public's health and the need to cooperate in public alerts.

Going public
The following guidelines are designed to assist in deciding whether potentially exposed patrons should be alerted via the news media. In applying these criteria and judging the risk of further spread of infection, the PHU should:

• Make every possible effort to obtain accurate information
• Exercise considerable judgment about the accuracy of information received, especially the consistency of hygiene information received from different sources
• Consider the record of the facility's food inspections records while under its current management
• Determine whether the manager has had food safety training and applies it through employee training, supervision and hazard control systems at the facility. Good practices include:
  • Management supervises and inspects food protection and food handling practices of all shifts on a routine basis
  • Training addresses personal hygiene and supervision of food handler hand washing practices
  • Management has established a routine means of evaluating employee performance such as watching that all food handlers wash their hands upon entering a food preparation area in addition to restroom hand washing
  • Hand washing facilities are checked frequently each day for adequate supplies and operation
  • High risk food handling tasks are designed so that direct handling of food and cross contamination are minimised
  • An effective management policy is in place for encouraging employees not to work with symptoms, that could indicate a communicable disease (e.g., diarrhoea or vomiting), thereby encouraging employees to report illnesses to management.

High Risk Food is defined as food that is handled and not subsequently cooked before consumption (e.g., salad fixings, cake icing, sliced fruit).

General principles for decision-making
Generally, infectious food handler situations fall into one of three categories. The decision-making process is unique for each of them. In all cases, other food handlers at the establishment in question should be evaluated to determine whether any have, or recently have had, hepatitis A. If other food handlers are found to be infected, the risk to patrons should be re-evaluated. The PHU and food service managers should monitor other food handlers who are at risk for hepatitis A for one incubation period (50 days) after their last exposure to the index case.

Food handler has not handled any high risk food.
Notification of potentially exposed patrons is rarely necessary.

Food handler handles high risk foods, but facility manager has received food service safety training and uses a hazard control system.
If the case always uses gloves or utensils appropriately, then public notification generally is rarely necessary. Glove use per se is not a panacea, however, and at worst can create a false sense of security. The potential for breaks in proper practices should be carefully evaluated.

If the food handler has handled high risk foods with bare hands, but the facility manager can document receipt of approved training and implementation of an approved hazard control system, public notification is usually not indicated, if the following conditions are met:

• No transmission within the facility to co-workers or to patrons has been documented
• The record of inspections of the facility under present management indicates that both personal hygiene of food handlers and the facilities for food handlers to wash hands have met inspection standards
• Inspection of the facility after identification of the case reveals that hand washing facilities for employees are adequate
• Information obtained from the infected food handler, supervisor, and other reliable sources indicates that the infected food handler followed optimum hand washing practices
• The infected employee, while potentially infectious, did not handle high risk foods on days when experiencing diarrhoea.

The food handler handles high risk food, and the manager has not received training and/or does not have an approved hazard control system.
If the food handler has handled high risk foods and the facility manager has not received training within the last three years and/or does not use a hazard control system, notification of potentially exposed patrons through the news media should be considered, especially if one or more of the following criteria is met:

• Transmission within the facility to co-workers or to patrons has already been documented
• Inspection of the facility after identification of the case reveals that hand washing facilities for employees in the food preparation area or the employees toilet facility are inadequate (e.g., no soap, no towels, no running water)
• One or more food handlers are not conforming to good hygienic practices (e.g., food handlers are not washing their hands on arrival at work or after using the toilet)
• The record of inspections of the facility under the present management indicates that personal hygiene of food handlers or facilities for food handlers to wash their hands have been a problem two or more times during the previous two years
• The infected employee, while potentially infectious, handled high risk foods on days when experiencing diarrhoea
• Information obtained from the infected food handler, supervisor, or other reliable source indicates that the infected food handler did not follow good hand washing practices or failed to appropriately use gloves or utensils, (e.g., didn't change gloves when food preparation was interrupted for a non-food preparation task)
• The infected food handler in the facility handled high risk foods with bare hands, (e.g., failed to use gloves or utensils).

Consult with the Communicable Disease Branch (CDB) staff and the Media Unit before going public. CDB may convene an expert panel to advise in difficult cases.