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close this bookWHO Recommended Surveillance Standards (WHO; 1999; 157 pages)
View the documentAcknowledgements
View the documentAcronyms
View the documentIntroduction
View the documentNational Coordination of Communicable Disease Surveillance
View the documentExplanatory notes
View the documentSurveillance activities: criteria and WHO Department
View the documentCommunicable disease contacts in Regional Offices
close this folderDiseases
View the documentB20-B21-B22-B23-B24 AIDS
View the documentA22 Anthrax
View the documentA23 Brucellosis
View the documentA00 Cholera
View the documentA81.0 Creutzfeldt-Jakob disease
View the documentA90, A91 Dengue fever (A90) including Dengue haemorrhagic fever (DHF) & Dengue shock syndrome (DSS, A91)
View the documentA36 Diphtheria
View the documentB72 Dracunculiasis (Guinea worm disease)
View the documentA98.3, A98.4 Ebola-Marburg viral diseases
View the documentA83.0 Japanese encephalitis
View the documentB74 Lymphatic filariasis
View the documentB96.3 Haemophilus influenzae type b
View the documentB15-B17 Acute viral hepatitis
View the documentB20-B24 HIV infection
View the documentJ10, J11 Influenza
View the documentA96.2 Lassa fever
View the documentA48.1 Legionellosis
View the documentB55.1, B55.2 Cutaneous leishmaniasis
View the documentLeishmania / HIV co-infections
View the documentB55.0 Visceral leishmaniasis
View the documentA30 Leprosy
View the documentA27 Leptospirosis
View the documentB50-54 Malaria
View the documentB05 Measles
View the documentA39 Meningococcal disease
View the documentA87 Viral meningitis
View the documentB73 Onchocerciasis
View the documentA37.0 Pertussis
View the documentA20 Plague
View the documentA36 Poliomyelitis
View the documentA82 Rabies
View the documentA02.0 Salmonellosis
View the documentB65 Schistosomiasis
View the documentA50-52 Syphilis
View the documentA33 Tetanus, neonatal
View the documentB56-0, B56-1 African trypanosomiasis
View the documentB57 American trypanosomiasis
View the documentA15-A19 Tuberculosis
View the documentA75.3 Scrub typhus
View the documentA95.9 Yellow fever
open this folder and view contentsSyndromes
View the documentAnnex 1 Software free and in the public domain
View the documentAnnex 2 Proposed surveillance definitions
View the documentAnnex 3 Role and use of Geographic Information Systems (GIS) and mapping for epidemiological surveillance
 

B20-B24 HIV infection

RATIONALE FOR SURVEILLANCE

The surveillance of HIV infection is the best way to forecast the future impact of AIDS on national health resources. It may also allow counselling, follow-up and chemoprophylaxis when appropriate at an individual level.

RECOMMENDED CASE DEFINITION

Clinical description

There is no clinical description; the diagnosis is based on laboratory criteria.

Laboratory criteria for diagnosis

HIV positive serology (ELISA)

Confirmation by a second serological test is necessary only in settings where estimated HIV prevalence is known to be <10%.

Confirmation should be a second ELISA or simple/rapid assay based on a different antigen preparation and/or a different test principle.

Case classification

 

Suspected: Not applicable.
Probable: Not applicable.
Confirmed: A laboratory-confirmed case.

 

Note: Except for unlinked anonymous testing, serological testing should only be done in combination with appropriate pre- and post-counselling services. Western Blot is used for individual confirmation rather than for general HIV surveys, in countries which have the appropriate resources.

RECOMMENDED TYPES OF SURVEILLANCE

In countries where HIV prevalence is low (e.g., ≤1% among pregnant women or other groups representative of the general population) and where infections are concentrated in a few high-risk sub-groups of the population, the current trend is to monitor the scope and course of the epidemic through HIV case reporting (HIV case surveillance). This approach is currently used mainly in developed countries, where a majority of those who are HIV positive have access to testing and are actually tested.

In areas of relatively high prevalence and in developing countries, the method of preference is unlinked anonymous testing in sentinel sites. In order to monitor time trends it is necessary to ensure continuity of the same sentinel surveillance sites over time, and to ensure that within sites the same sampling scheme is used over time (periodical and standardized).

For countries with low prevalence, the sentinel sites should focus on testing of high-risk groups (patients seeking treatment for sexually transmitted diseases, users of intravenous drug use, or commercial sex workers seeking health care treatment etc.).

For countries with higher prevalence, monitoring of high risk groups should continue, and surveillance of general population groups such as pregnant women attending antenatal clinics should be carried out.

Routine yearly reporting of HIV prevalence data from each sentinel site to intermediate and to central level. Some countries report case-based data. Other sources of data:

 

• Hospitals
• Antenatal clinics
• Dermatologists
• STD clinics
• Blood banks
• Army (data from army recruits)
• Special surveys
• Mortality reports

RECOMMENDED MINIMUM DATA ELEMENTS

Case-based data for reporting

 

• Age, sex, location, risk factors

Aggregated data for reporting

 

• On a yearly basis: number of cases tested by age, sex, patient group, sentinel site (where appropriate)

RECOMMENDED DATA ANALYSES, PRESENTATION. REPORTS

 

• Analysis of prevalence by age and sex and geographic area, rural/urban locations and population subgroups, risk factors

• Analysis of trends in prevalence over time, by age and sex and geographic area, rural/urban location and population subgroup

• Graphs and tables: prevalence and confidence intervals, by year, age and sex, by sentinel site, population subgroup, geographic area, rural/urban location

• Maps: prevalence levels at each sentinel site


At national level, show median value for sentinel sites, with minimum and maximum values observed.

PRINCIPAL USES OF DATA FOR DECISION-MAKING

 

• Assess the current magnitude and current trends of the HIV/AIDS epidemic
• Project the number of AIDS cases over the next 5 years
• Identify high risk population sub-groups and/or geographic areas for intervention
• Evaluate the impact of specific interventions
• Assess impact on health services, plan health and social service activities for people with HIV/AIDS
• Increase public and political awareness of the disease

SPECIAL ASPECTS

None.

CONTACT

Regional Offices

See Regional Communicable Disease contacts on section "Communicable disease contacts in Regional Offices".

Headquarters: WHO, 20 Avenue Appia, CH-1211 Geneva 27, Switzerland

UNAIDS/WHO Working Group on Global HIV/AIDS and STD Surveillance

E-mail: surveillance@unaids.org / Surveillancekit@who.ch
Tel: (41 22) 791 2403/2526
Fax: (41 22) 791 4198

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