Improving HIV testing for children and adolescents is vitally important, because children and adolescents experience a disproportionate amount of HIV-related illness and death compared to adults. Although children and adolescents aged up to 19 years old were only 7% of the global population living with HIV in 2021, they represented 17% of HIV-related deaths. This is due, in part, to late diagnosis of HIV. 

A new approach to finding undiagnosed children living with HIV, known as index-linked testing, has been recommended by the World Health Organisation to improve diagnosis rates. Index-linked testing involves targeting of HIV testing to children of people living with HIV (known as indexes). This focused approach has the potential to find more children living with HIV and be more cost-effective than blanket testing approaches.

The “Bridging the Gap in HIV Testing and Care for Children in Zimbabwe” (B-GAP) study evaluated index-linked HIV testing for children aged between two and 18 years old at nine primary care clinics, covering both rural and urban areas. People living with HIV in a household with one or more children of unknown HIV status, or with a known HIV negative result more than 6 months ago, were eligible to take part in the study. Those who consented to have children tested could choose either a test at the clinic, a test at home delivered by a community healthcare worker (HCW), or a test at home delivered by a caregiver using an oral HIV self-test. B-GAP provided an opportunity to examine implementation in-depth, so lessons could be learned for future roll-out.

The B-GAP team kept in touch via two long-running WhatsApp chats, one for the whole field team, and the other for the rural areas only. We used those WhatsApp chats, as well as field team logs, meeting minutes, and incident reports, to identify barriers and facilitators to scale-up of index-linked testing. Data from each source was analysed thematically.

The WhatsApp chats deepened our understanding of implementation. In the chats, the team often offered more comprehensive opinions on successes and challenges than in other sources. For example, one chat had detailed discussion on difficulties coordinating with partner organisations who were delivering HIV testing of children in the community. This clarified the underlying reasons why these challenges were occurring, such as differences in aims between the partner organisations and the research team, as well as resource constraints faced by partner organisations. The chats also provided a real-time and dynamic account of events, such as stock-outs of HIV test kits, over time.

However, WhatsApp chats required more effort to analyse than the other sources. As the chats were an informal record, sometimes it was challenging to work out what researchers were referring to in their messages. Unlike with the other sources, the team presumed readers had prior knowledge of what was being discussed, making it difficult for an outsider to follow the conversation. Moreover, sometimes researchers met face-to-face or communicated using other technology, which led to sudden jumps in the topics being covered in the chats.

Nonetheless, through analysing the WhatsApp chats and other sources, we identified a range of challenges to index-linked testing for children. These are illustrated in the flow diagram to the right. Some challenges were recognised barriers to provision of many forms of HIV testing, such as stock-outs of HIV test kits, difficulties reaching clinics, and stigma around HIV. However, we also identified some unexpected challenges, such as indexes sending someone else to the clinic on their behalf, and a lack of familiarity with oral HIV testing, which resulted in low uptake. As index-linked HIV testing for children is used more widely it will be critical to find ways to ensure these challenges can be overcome.

The WhatsApp chats gave us valuable insight into the barriers and facilitators of index-linked HIV testing. It is important to consider newer technologies and social media alongside traditional sources of data to fully capture the complexity of implementation of public health interventions. By doing so, we can more effectively address barriers to delivery of interventions and ultimately improve health outcomes.

Read more about the B-GAP study and its findings in the following publications:

1. Delivery of index-linked HIV testing for children: learnings from a qualitative process evaluation of the B-GAP study in Zimbabwe
2. Comparison of index-linked HIV testing for children and adolescents in health facility and community settings in Zimbabwe: findings from the interventional B-GAP study
3. Addressing the challenges and relational aspects of index-linked HIV testing for children and adolescents: insights from the B-GAP study in Zimbabwe 
4. Feasibility and Accuracy of HIV Testing of Children by Caregivers Using Oral Mucosal Transudate HIV Tests