Accurate testing is critical to stopping an outbreak. When one person is confirmed positive for the disease, they can be put in isolation. Then, their contacts can be identified and put into quarantine, as well, effectively curtailing the spread of the disease.

And yet, the US has been extremely slow to roll out diagnostic testing for the coronavirus (Covid-19). A combination of factors has held up the development and distribution of a sanctioned Covid-19 diagnostic test, including the monopolisation of development by the Centers for Disease Control and Prevention (CDC) and a faulty test reagent that caused a massive setback just when the CDC had finally started distributing the test to the states.

In general, viral respiratory infections are detected using real-time reverse-transcriptase (RT) polymerase chain reaction (PCR) tests. PCR is a common tool used to detect the presence of a pathogen, using nuclear probes for a specific section of DNA. To successfully perform PCR, the reaction (e.g. reagents, DNA sample, etc.) must be very clean. Any cross-contamination between samples or from previous reactions can return a false result. To control this, a ‘negative control’ reaction is included to ensure the quality of the results. A negative control is a control reaction that contains all of the same components of the PCR reaction except the viral sample.

In the US, the only Covid-19 diagnostic test available was through the CDC. Having only one national governing body in control of this created a significant bottleneck in testing suspected patients and curbing the spread and of the disease. Disaster struck when issues arose with one of the test reagents, the negative control, which cast doubt on the validity of the test itself when the CDC finally made the test available to other states, as reported by the journal Science, on 28 February.

In stark contrast to the 2,000 coronavirus tests done by the US so far, as sourced by the Atlantic, South Korea has already performed more than 140,000 coronavirus tests. The quick response of the South Korean Government to roll out testing, including programmes such as drive-through testing stations, to the Covid-19 outbreak is seen as one of the major reasons that the mortality rate is only 0.6% as compared to the current global mortality rate of 3.4%, as estimated by the World Health Organization.

In Seattle, the US city with the most Covid-19 cases, the Bill and Melinda Gates Foundation has committed $5m to battle the outbreak in the area, which includes the development of home testing kits for Covid-19. This would enable people in Seattle to swab their noses and send the samples back for analysis, which would encourage testing and prevent an overflow of patients coming into healthcare centres once state-wide testing becomes available. With more and more states advocating for regional control of Covid-19 testing, GlobalData expects Covid-19 diagnostic tests in the US to reach thousands every day.