Coronavirus: Reports of new US infections expected to rise amid boost in testing capacity

Local health authorities in US states and counties are likely to announce new coronavirus cases more rapidly as they use commercial diagnostic kits that have received quick approval, a top CDC official said on Tuesday. Meanwhile, questions continued to swirl over a Trump administration official’s claim that “close to one million tests” could be performed by the end of the week.

The Centres for Disease Control's Nancy Messonnier, however, said that while the commercial tests would give local authorities “actionable results”, the findings still would have to confirmed by the CDC. The federal health agency will have the capacity to confirm the results of up to 75,000 tests by Friday, said Messonnier, director of the National Centre for Immunisation and Respiratory Diseases. Commercial tests will give local authorities “actionable results” to make public health decisions about so-called presumptive positive cases, but are not considered proof of infection, she said.

“It's a good thing that these tests are going to be widely available, but it also means that the CDC will not always be up-to-the minute in terms of the latest number of cases, especially [compared to] state and local health departments,” Messonnier said.

“That’s why we say we really do need you to look to the states for those updated numbers. CDC may be a little more delayed because there are so [many] testing kits going out,” she said. While the administration is seeking to shore up public confidence by claiming it can ramp up testing quickly through the use of privately manufactured test kits, Messonnier's comments showed that the process is not so straightforward.

Some confusion ensued in public health circles after the Food and Drug Administration's (FDA) commissioner Stephen Hahn on Monday said emergency approval granted by his agency allowing private labs and companies to produce their own tests meant that “by the end of this week, close to a million tests will be able to be performed”.

The FDA later said he was taking into account ramped-up manufacturing by a commercial producer of the tests that it was working with – which did not necessarily mean testing capacity would immediately be ramped up.

US public health researchers have questioned whether kinks in testing – and a sluggish expansion of local testing – for the Covid-19 disease may be a reason that community transmission is occurring in the US. Early on in the global outbreak of the virus, the CDC developed its own diagnostic test, but has since acknowledged that they were faulty in some instances.