The extraordinary success of Singapore, Taiwan and Hong Kong in limiting the impact of the sudden acute respiratory syndrome coronavirus-2 (SARS-CoV-2) demonstrates that it is possible to mount an effective response to an outbreak by major investment in pandemic preparedness. Despite their proximity to China, these three regions have managed to keep case numbers and fatalities low. By learning from previous coronavirus outbreaks where these territories bore the brunt, they were able to rapidly deploy widespread testing, combine it with digital surveillance to trace individuals’ movements, and impose strict quarantines in suspect cases, in addition to building large stockpiles of personal protective equipment.
The first quantitative reverse-transcriptase-based PCR (RT-PCR) tests for detecting SARS-CoV2 were designed and distributed in January by the World Health Organization (WHO), soon after the virus was identified. The test protocol is complex and expensive, however, and is mainly suited to large, centralized diagnostic laboratories. Tests typically take 4–6 hours to complete, but the logistical requirement to ship clinical samples means the turnaround time is 24 hours at best
Point of Care Testing
POC tests are needed as well to accelerate clinical decision-making and to take some of the workload off centralized test laboratories. Rapid POC tests for use at community level were identified by a WHO expert group convened in Geneva last month as the first of eight research priorities. The Foundation for Innovative New Diagnostics (FIND), a Geneva-based not-for-profit that supports the development and delivery of diagnostics to low-income countries, is aiding that broad effort by inviting assay developers to submit their products for independent evaluation. It has received 220 submissions, which are being assessed, and qualifying manufacturers will be contacted by the end of this month.
Immunoassays can provide historic information about viral exposure, as well as diagnostic evidence. They exploit antibody–antigen recognition, either by using monoclonal antibodies (mAbs) to detect viral antigens in clinical samples or by using cloned viral antigens to detect patient antibodies directed against the virus.