Human immunodeficiency virus (HIV) and acquired immunodeficiency syndrome (AIDS)

Notification requirement for HIV infection and AIDS

HIV is a ‘routine’ notifiable condition and must be notified by medical practitioners and pathology services in writing within 5 days of diagnosis.

AIDS is not notifiable.

To maintain confidentiality, only the name code (the first two letters of the surname followed by the first two letters of the first name) is required.

This is a Victorian statutory requirement.

Primary school and children’s services centre exclusion for HIV infection and AIDS

Exclusion is not required.

Infectious agent of HIV infection and AIDS

Human immunodeficiency virus (HIV) types 1 and 2 are members of the family Retroviridae. A number of subtypes exist within HIV-1 and HIV-2.

Identification of HIV infection and AIDS

Clinical features

AIDS is a severe, life-threatening disease that represents the late clinical stage of infection with HIV. HIV weakens the immune system by destroying a type of white blood cell (CD4 or T-helper lymphocytes). Several weeks after infection with HIV, a number of infected individuals will develop a self-limiting glandular fever–like illness lasting for a week or two (seroconversion illness). Infected people may then be free from clinical signs or symptoms for months or years.

Treatment with combination antiretroviral therapy (cART) has resulted in vast reductions in cases of AIDS and mortality. The burden of illness is now increasingly due to non-AIDS infections and malignancies, neurological and psychiatric manifestations of HIV, and coronary artery disease accelerated by a pro-inflammatory state induced by HIV. Newer cART regimens are much less toxic, but significant long-term side effects (including effects on blood glucose, cholesterol and bone health) still occur.

Untreated individuals are at risk of specific opportunistic infections and malignancies, and a range of other AIDS-defining illnesses, including:

• Pneumocystis jirovecii pneumonia
• oesophageal candidiasis
• Kaposi’s sarcoma
• chronic herpes simplex infection, or herpetic oesophagitis
• cryptococcosis
• cryptosporidiosis
• toxoplasmosis
• cytomegalovirus infection
• mycobacteriosis, including tuberculosis
• lymphoma
• HIV encephalopathy
• HIV wasting disease
• recurrent bacterial pneumonia
• progressive multifocal leukoencephalopathy.

Diagnosis

Careful history and physical examination, looking for risk factors and clinical manifestations of immunodeficiency, are necessary.

Diagnostic testing generally involves detection of HIV antibody/p24 antigen by a fourth-generation combination screening test, and confirmation by western blot analysis. Molecular techniques, such as polymerase chain reaction (PCR) to detect proviral DNA sequences, are occasionally necessary to clarify indeterminate results.

Incubation period of HIV

The period from infection to the primary seroconversion illness is usually 1 to 4.weeks. The period from infection to development of anti-HIV antibodies is usually less than 1 month but may be up to 3 months; newer tests have a shorter window period, where a false negative result may be obtained early in infection.

The interval from HIV infection to the diagnosis of AIDS ranges from about 9 months to 20 years or longer, with a median of 12 years. There is a group of people with a more rapid onset of disease who develop AIDS within 3–5 years of infection, and another smaller group who do not seem to progress to AIDS.

Public health significance and occurrence of HIV infection and AIDS

Occurrence is worldwide. More than 30 million people were living with HIV/AIDS by the end of 2009, and an estimated 1.8 million people died from HIV-related illnesses that year. The vast majority of HIV infections occur in developing countries.

For the period 1983–2003, there was a cumulative total of 4,680 HIV diagnoses in Victoria. This represents about 21 per cent of Australia’s total. Males accounted for 94 per cent of the diagnoses. Male-to-male sexual contact, including homosexual and bisexual contact, accounts for the majority of new diagnoses in men. In females, heterosexual contact and injecting drug use are the most common risk factors.

Reservoir of HIV

Humans are the reservoir.

Mode of transmission of HIV

HIV can be transmitted from an infected person by:

• sexual exposure to infected semen, vaginal fluids and other infected body fluids during unprotected sexual intercourse with an infected person; this includes unprotected oral sex Transmission risk following unprotected anal or vaginal sex with a person with HIV is estimated to be 0.1–2 per cent. It is highest following unprotected receptive anal intercourse
• inoculation with infected blood or blood products, transplantation of infected organs such as bone grafts or other tissues, or artificial insemination with infected semen
• breastfeeding of an uninfected infant by an HIV-positive mother. Use of cART during pregnancy decreases the risk of vertical transmission from an infected woman to her child; caesarean section may be recommended if an infected mother has a detectable viral load. Avoiding breastfeeding decreases transmission postpartum; newborns are commonly given ART as post-exposure prophylaxis for potential exposure to HIV during delivery. With these interventions, the risk of mother-to-child HIV transmission is less than 5 per cent. If there is no intervention, including cART during pregnancy, the risk of mother-to-child HIV transmission has been estimated to be 20–45 per cent.
• sharps injuries, including needlestick injuries or other exposure to blood and body fluids. The rate of seroconversion following a needlestick injury involving HIV-infected blood is said to be less than 0.5 per cent, but this is dependent on the type of needlestick injury (deep versus shallow) and the viral load of the infected person. Post-exposure prophylaxis following needlestick injury is given in cases of known HIV-infected blood or body fluids, or high-risk exposures.

Period of communicability of HIV infection and AIDS

All antibody-positive people carry the HIV virus.

Infectivity is presumed to be lifelong, although successful therapy with cART can lower the viral load in blood and semen to undetectable levels.

Susceptibility and resistance to HIV infection

Everyone is susceptible to infection.

The presence of other sexually transmissible infections, especially those with skin or mucosal ulceration, may increase susceptibility.

Control measures for HIV infection

Preventive measures

Preventive measures for HIV centre on personal and institutional factors.

Personal factors include the following:

• Public education should be provided on the use of condoms and safer sex practices.
• Public education should stress that having unprotected sex with unknown or multiple sexual partners and sharing needles (drug users) increase the risk of infection with HIV.
• Unprotected sexual intercourse with people with known or suspected HIV infection should be avoided.
• HIV-infected people should be offered confidential counselling, access to screening and treatment for sexually transmissible infections, and appropriate antiviral therapy for HIV.
• Care should be taken when handling, using and disposing of needles or other sharp items.
• Use of needle exchange programs by injecting drug users should be facilitated.

Institutional factors include the following:

• Appropriate infection control measures (standard precautions) should be used by all healthcare and emergency workers.
• Appropriate infection control measures should be used in all premises where skin penetration is carried out – for example, electrolysis, tattooing or body piercing.
• Blood and blood products for transfusion, and the donors of tissues and body fluids, such as semen, should be assessed for risk and tested for the presence of markers of HIV.
• Sharps injuries, including needlestick injuries, and parenteral exposure to laboratory specimens containing HIV should be dealt with according to Australian guidelines for the prevention and control of infection in healthcare.
• Nonoccupational exposure to infected blood or body fluids should be assessed and managed according to Australian national guidelines for post-exposure prophylaxis after non-occupational exposure to HIV.

Control of case

See ‘Standard precautions – Appendix 3’ of the Blue Book, which applies to all patients.

Additional transmission-based precautions apply for specific infections that occur in AIDS patients, such as tuberculosis. Equipment contaminated with blood or body fluids should be cleaned, and then disinfected or sterilised as appropriate.

Patients and their sexual partners should not donate blood, organs or other human tissue.

All HIV-infected people should be evaluated for the presence of tuberculosis.

Treatment

Antiretroviral drug therapy is used to treat established HIV infection. Because such treatment is specialised and constantly changing, only those doctors experienced in HIV management should prescribe antiretroviral therapy. For further information, see the current edition of Therapeutic guidelines: antibiotic and the Australasian Society for HIV Medicine website. Other treatment includes specific treatment or prophylaxis for the opportunistic infectious diseases that result from HIV infection.

Control of contacts

If a person is diagnosed as having HIV infection, the diagnosing practitioner has a responsibility to ensure that sexual and needle-sharing contacts are followed up, where possible.

Assistance with partner notification may be provided by the department through its partner notification officers.

Pre- and post-test counselling must be provided for all contacts seeking HIV testing.

Control of environment

The procedure for dealing with spills of blood and body fluids is in Appendix 5.

Outbreak measures for HIV infection

The epidemiology of HIV is closely monitored in Victoria. Public health action is informed by enhanced epidemiological information notified to the department.

Special settings

Healthcare workers

Registration boards should be consulted in relation to their policies regarding healthcare workers with bloodborne viruses. F. Recommendations are also included in the Communicable Diseases Network of Australia publication, Australian Guidelines for the management of health care workers known to be infected with blood-borne viruses.

Antenatal care

Antenatal care should include a comprehensive assessment of HIV risk factors. All pregnant women should be encouraged to undergo HIV testing after appropriate pre-test counselling.

Other settings

All workplaces should have policies and procedures in place regarding action to be taken in the event of a blood spill or sharps injury. Refer to Australian guidelines for the prevention and control of infection in healthcare.

International measures

The World Health Organization initiated a global prevention and control program in 1987. Since 1995, the global AIDS program has been coordinated by the Joint United Nations Programme on HIV/AIDS (UNAIDS). Nearly all countries have developed an AIDS prevention and care program.

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