Digital contact tracing is not as effective as manual contact tracing, Otago University researchers says.
University of Otago-led research published in the Cochrane Library today revealed contact tracing apps could reduce the number of cases, but not as much as manual contract tracing.
The research concluded there was "very low certainty evidence" that contact tracing apps could make a substantial impact on the spread of Covid-19, as long as issues of low adoption, technological variation and health equity persisted.
But the team of researchers, from New Zealand, the USA, the UK and Australia, said there was still a place for digital technologies in contact tracing.
Department of Preventive and Social Medicine senior research fellow Dr Andrew Anglemyer led a systematic review of the effectiveness of digital technologies for identifying contacts of an identified positive case of an infectious disease, in order to isolate them and reduce further transmission of the disease.
Six observational studies from outbreaks of different infectious diseases in Sierra Leone, Botswana and the USA, and six studies that simulated the spread of diseases in an epidemic with mathematical models were carried out.
The results found a need for caution by health authorities relying heavily on digital contact tracing systems.
"Digital technologies, combined with other public health interventions, may help to prevent the spread of infectious diseases but the technology is largely unproven in real-world, outbreak settings," Dr Anglemyer said.
"Modelling studies provide low certainty of evidence of a reduction in cases, and this only occurred when digital contact tracing solutions were used together with other public health measures such as self-isolation.
"However, limited evidence shows that the technology itself may produce more reliable counts of contacts."
Governments should also consider issues of privacy and equity when choosing digital contact tracing systems.
Dr Anglemyer said the pandemic was disproportionately effecting ethnic minorities, the elderly and people living in high deprivation, and that could be magnified by using digital solutions that do not consider these at-risk populations, who were likely to have poor access to smartphones with full connectivity.
The research identified system access issues such as patchy network coverage, lack of data, technical problems with hardware or software that were unable to be resolved by local technical teams, and there was also a need for higher staff training, including the need for refresher training.
Concerns were also raised around accessibility and logistical issues in administering the systems, particularly in marginalised or under-developed areas of the world.
But contact tracing teams reported that digital data entry and management systems were faster to use than paper systems for recording of new contacts and monitoring of known contacts, and were possibly less prone to data loss.
They suggested that governments consider digital technologies as a way to improve current contact tracing methods, rather than to replace them.
"In the real world, they won’t be pitted against each other, the technology would hopefully just augment the current contact tracing methods in a given country," Dr Anglemyer said.
The research was carried out as the Covid-19 pandemic shows no signs of waning and the World Health Organization and more than 30 countries are exploring how digital technology solutions could help stop the spread of the virus.
University of Otago, Wellington senior research fellow Tim Chambers and Department of Statistics associate professor Matthew Parry were also co-authors of the paper.