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Trends in CD4 and viral load testing 2005 to 2018: multi-cohort study of people living with HIV in Southern Africa (lay summary)

This is a lay summary of the article published under the DOI: 10.1002/jia2.25546

Published onApr 30, 2023
Trends in CD4 and viral load testing 2005 to 2018: multi-cohort study of people living with HIV in Southern Africa (lay summary)

Researchers say inconsistent HIV testing threatens treatment in sub-Saharan Africa 

The effectiveness of anti-HIV treatment in southern Africa is at risk, said researchers, because inconsistent or declined HIV testing might miss patients who suffer with advanced disease or those for whom treatment is not working.

A person’s HIV status is commonly checked using a test called a “CD4 cell count”, which measures the number of immune cells (called CD4 cells) that are actively fighting the infection. Doctors can also check a patient’s viral load (VL), which is the number of HIV particles in their body, if they want to know how well treatment is working to suppress the virus.

The World Health Organisation (WHO) recommends a CD4 cell count before a patient starts antiretroviral therapy (ART) to determine if a person has advanced HIV disease, and they suggest routinely checking viral load once treatment has started to make sure it is working.

In this study, researchers wanted to find out how CD4 cell counts and viral load testing is being used to monitor HIV status and treatment success in patients in southern Africa.

They analysed data from more than 500 000 patients in HIV treatment programmes within Lesotho, Malawi, Mozambique, South Africa, Zambia and Zimbabwe, during the years 2005 to 2018.

Their key finding was that CD4 cell count testing declined over time, and viral load testing trends to monitor treatment success were inconsistent. As mentioned above, CD4 cell counts are important to detect advanced HIV disease before starting treatment, but researchers said this testing declined despite the fact that many patients did initiate treatment with advanced HIV disease. 

The findings from this study showed that the countries had drastically reduced their CD4 counts, but this is a problem because CD4 testing is important in finding out the stages of HIV and should still be used before the patients start their therapy.

Researchers caution however that their study has several limitations. For instance, the patient data they used did not represent different regions as a whole. Also, differences in lab testing could have skewed results, and they couldn’t account for missing patients who had stopped or changed treatment, or died.

The researchers say that without CD4 testing and expanded viral load testing, patients who have advanced HIV disease, or patients for whom treatment doesn’t work, may go undetected, which undermines the success of antiretroviral therapy in southern Africa.

The authors of this paper were from Africa, the United States and the United Kingdom. 


Introduction: The World Health Organization (WHO) recommends a CD4 cell count before starting antiretroviral therapy (ART) to detect advanced HIV disease, and routine viral load (VL) testing following ART initiation to detect treatment failure. Donor support for CD4 testing has declined to prioritize access to VL monitoring. We examined trends in CD4 and VL testing among adults (≥15 years of age) starting ART in Southern Africa. Methods: We analysed data from 14 HIV treatment programmes in Lesotho, Malawi, Mozambique, South Africa, Zambia and Zimbabwe in 2005 to 2018. We examined the frequency of CD4 and VL testing, the percentage of adults with CD4 or VL tests, and among those having a test, the percentage starting ART with advanced HIV disease (CD4 count <200 cells/mm3 ) or failing to suppress viral replication (>1000 HIV-RNA copies/mL) after ART initiation. We used mixed effect logistic regression to assess time trends adjusted for age and sex. Results: Among 502,456 adults, the percentage with CD4 testing at ART initiation decreased from a high of 78.1% in 2008 to a low of 38.0% in 2017; the probability declined by 14% each year (odds ratio (OR) 0.86; 95% CI 0.86 to 0.86). Frequency of CD4 testing also declined. The percentage starting ART with advanced HIV disease declined from 83.3% in 2005 to 23.5% in 2018; each year the probability declined by 20% (OR 0.80; 95% CI 0.80 to 0.81). VL testing after starting ART varied; 61.0% of adults in South Africa and 10.7% in Malawi were tested, but fewer than 2% were tested in the other four countries. The probability of VL testing after ART start increased only modestly each year (OR 1.06; 95% CI 1.05 to 1.06). The percentage with unsuppressed VL was 8.6%. There was no evidence of a decrease in unsuppressed VL over time (OR 1.00; 95% CI 0.99 to 1.01). Conclusions: CD4 cell counting declined over time, including testing at the start of ART, despite the fact that many patients still initiated ART with advanced HIV disease. Without CD4 testing and expanded VL testing many patients with advanced HIV disease and treatment failure may go undetected, threatening the effectiveness of ART in sub-Saharan Africa.


This summary is a free resource intended to make African research and research that affects Africa, more accessible to non-expert global audiences. It was compiled by ScienceLink's team of professional African science communicators as part of the Masakhane MT: Decolonise Science project. ScienceLink has taken every precaution possible during the writing, editing, and fact-checking process to ensure that this summary is easy to read and understand, while accurately reporting on the facts presented in the original research paper. Note, however, that this summary has not been fact-checked or approved by the authors of the original research paper, so this summary should be used as a secondary resource. Therefore, before using, citing or republishing this summary, please verify the information presented with the original authors of the research paper, or email [email protected] for more information.

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