ZNSP

Why Case-Based Surveillance

Zambia has made significant strides in addressing its HIV epidemic, with HIV prevalence declining from 15.6% in 2001-2002 to 11.5% in 2016. However, challenges remain in reaching key populations and ensuring equitable access to HIV services. To strengthen its HIV surveillance system, Zambia has been implementing case-based surveillance with support from the U.S. Centers for Disease Control and Prevention (CDC) and the U.S. President’s Emergency Plan for AIDS Relief (PEPFAR).

Case-based surveillance involves gathering detailed data on individuals living with HIV to monitor their care and treatment over time. This approach allows for a more detailed analysis of the HIV epidemic and program performance. Zambia’s HIV case surveillance system, based on the World Health organization (WHO) guidelines and implemented using the open-source Superset platform, includes components for data collection, analysis, and use to inform decision-making and enhance HIV service delivery across the country. Collected events include HIV positivity, entry to care, initiation on antiretroviral therapy, all laboratory, clinic and pharmacy visits, advanced HIV disease, and mortality.

Sentinel Events	Indicators	Definition	Comments/Notes
HIV Diagnosis	Number of persons newly diagnosed with HIV	Number of HIV+ Persons who have been newly diagnosed.	Stratification: 1. Newly diagnosed. 2. By Socio-demographic data (Age, Sex, location)
Enrolment in Care	1. Number of HIV+ persons that enrolled into care. 2. % of HIV+ persons enrolled into care.	Number and proportion of HIV+ persons who were linked into care.	Stratification: 1) Newly diagnosed (by year). 2) Among all HIV+ persons (ever). 3) By socio-demographic data (age, sex, geographical location)
All CD4 Counts	Baseline CD4 count	CD4 count at or closest to diagnosis before starting ART.	Stratified by socio-demographic data (age, sex, geographical location).
ART Initiation	1. # of HIV+ persons started on ART 2. Percentage of HIV+ persons started on ART	Number and proportion of HIV+ persons who ever started ART.	Stratification: 1) By year of diagnosis. 2) Among all HIV+ persons (ever). 3) By socio-demographic data (age, sex, geographical location).
Current on ART	Number and % of HIV+ persons who are currently on treatment.	HIV + persons who still have ARVs or a valid clinical appointment at the time of measurement.	Stratification: 1) By year of diagnosis. 2) Among people initiated on ART. 3) By socio-demographic data (age, sex, geographical location)
All VL Results	1) Number and % of HIV+ persons who are currently on treatment that are virally suppressed. 2) Number and % of HIV+ persons who are virally suppressed.	1) Number and proportion of HIV+ persons who are determined to be currently on treatment and should have a VL (6 or more months on treatment) that are virally suppressed (<1,000 copies/ml). 2) On a population level: How many HIV+ persons (regardless of treatment status) are virally suppressed.	1) Can be stratified by socio-demographic data (age, sex, geographical location). 2) The 2nd indicator currently not on dashboards but attaining 73% measures achievement on 90-90-90.
Advanced HIV	Number of HIV+ persons with advanced HIV	Number and proportion of HIV+ using WHO Staging and CD4 count	Stratification: 1) By socio-demographic data (age, sex, geographical location).
Death	Number of HIV+ persons who have died.	Number of HIV+ persons who have died.	1) Can be stratified by socio-demographic data (age, sex, geographical location). 2) Trends in deaths overtime. 3) All cause of death included. 4) When cause is available – we can stratify.