Despite a decrease in the number of HIV tests conducted in PEPFAR countries that began before the COVID-19 pandemic, the percentage of positive tests has remained stable at around 4%. More importantly, increasing numbers of people who test positive have initiated treatment, reaching 94% in 2021. This study was presented to the Conference on Retroviruses and Opportunistic Infections (CROI 2022) yesterday by Dr Bakary Drammeh from the US Centers for Disease Control and Prevention.
The US President’s Emergency Plan for AIDS Relief (PEPFAR) changed its universal HIV testing guidelines in 2019 and shifted instead to using targeted testing for those at the highest risk of acquiring HIV. PEPFAR now emphasises the tried and tested public health method of index testing – testing contacts of the person diagnosed with HIV who could be at risk. Another method is using HIV risk-screening algorithms to determine risk profiles of those in the general population most likely to have acquired HIV, and testing individuals in outpatient or community settings who score highly. It is hoped that this will increase testing efficiency and improve HIV case finding.
To evaluate trends in HIV testing and linkage to care, researchers analysed data from 41 PEPFAR countries for the period 2016 to 2021 for those 15 years and older. This included the number of HIV tests conducted overall and the number of positive results; these figures were used to calculate the percent positivity rate or yield – the number of HIV-positive test results divided by the total number of tests done.
The researchers also looked at how many individuals with a positive test started treatment during this period. This led to the calculation of a proxy linkage rate, or the number of individuals newly starting antiretroviral therapy divided by the number of positive tests.
Most of the 41 PEPFAR countries investigated are located in sub-Saharan Africa (22), with a further ten in Asia, six in the Caribbean, two in Central and South America and one in Europe. This represents 99.3% of PEPFAR’s overall HIV testing and treatment data.
Between January 2016 and June 2021, a total of 443 million HIV tests were conducted across the 41 countries. Of these, 17.5 million were positive.
There was a 42% increase in testing from 19 million tests in March 2016 to a peak of 27 million in September 2018. However, this number then decreased by 42% to 16 million tests in December 2019, following the implementation of the new PEPFAR guidelines and before the global pandemic. In June 2021, there were 15 million tests.
The number of positive results increased from around 900,000 in March 2016 to just under a million in September 2017. This number then decreased to 600,000 in June 2021.
The percent positivity rate was stable at around 5% between March 2016 and September 2017 and decreased to 3% in March 2018. It has subsequently been stable at around 4% since December 2019.
The number of people starting treatment increased from around 500,000 in March 2016 to 800,000 in September 2017. It decreased to 600,000 in June 2021, reflecting the reduction in the number of people being diagnosed with HIV.
The gap between diagnosis and linkage to care has narrowed: the proxy linkage rate increased from a low of 66% in March 2016 to 94% in June 2021, showing that the vast majority of those who test positive are now linked to care. Nonetheless, COVID-19 had an impact by lowering this figure during 2020.
Drammeh concluded that since 2018, the number of HIV tests decreased by five million, but the percent positivity rate has remained fairly stable, indicating the benefit of more focused testing efforts. Additionally, the number of newly diagnosed people linked to ART increased substantially during this period.
However, this analysis does not consider the number of people who remain undiagnosed by comparing positive tests with the current HIV incidence estimates in each country.
Dr Kevin de Cock, formerly a senior CDC and WHO official, asked Drammeh about the number of people who are undiagnosed: “The data show that the 2019 guideline change reduced the absolute number of tests and the overall number of positive tests without significant increase in yield. Therefore, more people with HIV went undiagnosed than previously due to this new policy. Will PEPFAR reverse this policy change?”
In his response, Drammeh acknowledged that there may be missed opportunities in terms of diagnoses, but did not indicate that the policy would change. He stated that PEPFAR has recently introduced additional risk-screening tools that will hopefully be sensitive enough to identify those at highest risk and who may remain undiagnosed.
Drammeh, B et al. Trends in HIV testing and linkage to HIV treatment in 41 countries, 2016-2021. Conference on Retroviruses and Opportunistic Infections, abstract 89, 2022.
This article was updated on 21 February 2022 to include Kevin de Cock's comments.