Introduction to an HIV Case Surveillance System

Case Finding

Identifying

reporting

sources

• 
  laboratories
  
• 
  healthcare clinics (health centres)
  
• 
  ART treatment clinics
  
• 
  TB clinics
  
• 
  voluntary HIV counselling and testing sites
  
• 
  hospice (initially)
  
• 
  hospitals
  
• 
  blood banks
  
• 
  programmes prevention of mother-to-child HIV transmission
  
• 
  vital statistics registries.
  

Educating

providers

Providers of case information should be educated regarding reporting requirements, including laws and regulations, case definitions, specific data elements, case surveillance forms, laboratory reports, and timeliness of reporting.

identify cases

New cases of HIV infection are found by both passive and active surveillance. The definitions of active and passive surveillance are:

• 
  Active surveillance: surveillance activity where the public health surveillance staff regularly contact reporting facilities (hospitals, clinics, physician offices, laboratories) to identify potential/suspect HIV cases.
  

• 
  Passive surveillance: surveillance activity that is initiated by persons at the health facilities—that is, the surveillance office receives HIV case reports from physicians, laboratories, or other individuals or institutions without regularly contacting the reporting sources.
  

Comprehensive case (surveillance) information may be contained in documents obtained by both active and passive surveillance. For example, the surveillance office may receive an electronic laboratory report through passive reporting. However, for complete case information, surveillance office staff may contact or travel to the diagnostic or treatment facilities to obtain the additional data items not provided on laboratory reports.

initiated

reporting

Identify all laboratories in your geographic area. If positive HIV EIA/WB or CD4 or viral load tests are reportable, work with the labs to develop a system where they can report cases to the surveillance unit in a confidential and timely manner. Special efforts should be made to automate systems as much as possible, so as not to cause unnecessary burden to the staff members. This will be critical to ensuring timely reporting of cases.

• 
  patient’s name or code
  
• 
  sex
  
• 
  date of birth
  
• 
  lab identifier
  
• 
  specimen collection date
  
• 
  date of test
  
• 
  type of test
  
• 
  test result
  
• 
  requester/provider name and telephone number.
  

Following up

with provider

Once a positive HIV test has been reported to the surveillance unit, the surveillance officer can follow up with the provider to obtain the remaining information on the case surveillance form.

information

It is important to update case information through disease progression from asymptomatic infection through to advanced HIV infection, AIDS and death.
Note: The HIV database needs to hold longitudinal data on cases without overwriting case information.
Duplicate cases

The surveillance system should be able to correctly distinguish newly reported persons from persons previously reported. Failing to properly link newly submitted case reports to previously reported cases leads to over-counting; incorrect linking of duplicate reports can result in under-counting and contamination of existing records with data from another case. Because doctors, hospitals, laboratories, and other sources may be required to report all HIV diagnoses whether or not they are newly identified, duplicate case reporting within a country may not be identified during routine case entry into the surveillance database (that is, duplicate case reports may not be readily identified as such). Eliminating duplicate reports on a regular basis is an important component of maintaining a reliable surveillance database and ensures accurate case counts at the national levels.

variables for

counting a cases

A minimum set of information must be available in order to count a patient as an HIV case.

• 
  case identifier (name or code)
  
• 
  sex
  
• 
  date of birth
  
• 
  date of diagnosis (specimen collection date or date of diagnosis by healthcare provider)
  
• 
  test result date
  
• 
  date of death (essential to accurately count the number of persons with HIV).
  

As an HIV case may be reported from multiple sources or from the same source multiple times, having a minimum set of required information allows the national surveillance unit to accurately match an individual to his/her record and ensure that each HIV case is only counted once. This is of particular importance when a previously reported patient progresses through the stages to advanced HIV disease, AIDS and death.

missed cases

Missed cases can be identified from:

• 
  anecdotal comments of cases not being reported
  
• 
  timeliness assessments that show cases reported more than six months after the diagnosis date
  
• 
  finding unreported cases by reviewing death certificates
  
• 
  matches with other databases
  
• 
  assessments of completeness of reporting from particular providers (See Unit 5).
  

Reporting chain

Each country must determine the reporting chain for HIV case reports. This may involve forwarding report forms from healthcare providers to a sub-national level, but ultimately HIV case reports should be sent to the national surveillance unit, where a complete database should be housed. This will allow de-duplication of cases reported from several sources, thereby giving a more accurate picture of the HIV situation for the country. At the national level, the office of the National Epidemiologist is responsible for the transmission of aggregate reports to CAREC.
Roles and

responsibilities

Roles and responsibilities of reporting sources:

• 
  complete one HIV case surveillance form for each person newly diagnosed with HIV infection
  
• 
  complete an HIV case surveillance form for each person who experiences a change in clinical status (for example, clinical diagnosis of HIV-advanced disease or AIDS, CD4 count less than 350, etc—see Figure 4.7)
  
• 
  complete an HIV case surveillance form for each HIV-infected person who dies (and include cause of death, if available)
  
• 
  submit forms to sub-national or national level surveillance unit, as per reporting chain for the country (under confidential cover, see Unit 7)
  
• 
  record each instance of case reporting to the surveillance unit on patient’s clinical record.
  

Roles and responsibilities of the national HIV surveillance programme:

• 
  solicit, receive, review and file HIV case surveillance forms on a timely basis
  
• 
  ensure case surveillance forms are filled out completely, accurately and clearly
  
• 
  evaluate each form to determine whether the case meets the criteria for HIV diagnosis
  
• 
  evaluate each case report to establish whether it contains enough information for determination of clinical stage (documentation of the clinical stage, clinical information that can be used to determine clinical stage, or immunological information, such as CD4 count/percent)
  
• 
  ensure that minimum data elements are documented (that is, demographic characteristics, geographic region, risk information, diagnosis date and report date)
  
• 
  conduct follow-up investigations on cases of epidemiologic importance
  
• 
  maintain a complete and accurate HIV surveillance database that is secure and accessible only to authorised personnel
  
• 
  identify reporting sources, provide an active liaison with physicians and institutions reporting cases, abstract medical records to generate case reports when necessary, and supply routine feedback to providers in cases reported
  
• 
  analyse, interpret and disseminate HIV surveillance data
  
• 
  critically assess the performance of the surveillance programmes through ongoing monitoring of surveillance activity.