HIV testing trial in Thailand increases retesting by 25%

A study in Thailand that tried out a simple and affordable approach to HIV testing has increased the number of at-risk people retesting for HIV.

The study took place in 2017 in four HIV and STI testing clinics in Chiang Mai and Chiang Rai, two cities in northern Thailand.

Around 650 people who tested HIV negative but were at an increased risk of getting HIV were put in three groups. Around 55% were men, the median age was 24, and 63% had never tested for HIV before.

People in the first group – the control – were told by the counsellor to return after three or six months depending on their level of risk for HIV, but were not given an appointment, nor a reminder.

In the second group, appointments were not immediately rebooked, but they did receive a text message asking them to return for re-testing after 24 weeks. They also received a reminder message a week later if they had not made an appointment.

People in the third group were given a retest appointment six months later. They also received a text message one week before their appointment asking for them to confirm that they would attend. If people did not respond, they received a phone call the next day.

Around 37% of the people booked in for an HIV retest and follow-up reminder (group three) returned for testing within seven months. This is compared to just 11% of people who did not have an appointment nor a reminder (group one – the control), and 19% who did not have an appointment but had been reminded to rebook (group two).

In the group that had been given an appointment and reminders, 8% of people confirmed their appointment after receiving the text message while 27% confirmed it after receiving the follow-up phone call. This suggests the personal nature of the phone call contributed to this approach’s effectiveness.

The two experimental reminder strategies were found to be affordable, at a total mean cost of less than US $1 per person. Both approaches were also highly cost‐effective. The cost of increasing HIV retesting by 5% was estimated to be an extra mean cost per person of less than US $0.15.

It is important to note that nearly one-third of those who were sent text reminders did not receive them. This is because some mobile operators block automatic text messages. It is also because some people’s mobile phone numbers were no longer active. Sending reminders through instant messaging platforms such as Whatsapp may be an alternative but this relies on people having internet access. Sending text reminders manually is one way to overcome the issue of blocked texts but may add significant cost.

The study’s authors had predicted that 25% of participants in the control group and 40% in each experimental group would return for HIV retesting within seven months. The fact that the results were lower overall is a cause for concern because frequent testing of people at higher risk of HIV is crucial for detecting and treating infections early and preventing HIV from spreading. But the trial does suggest that retesting will increase if new approaches are tried.