- The epidemic in China is likely much broader than official statistics currently suggest.
- A lot of mild cases probably remain unrecognized.
- Global spread appears inevitable. So too are the emergence of outbreaks in the U.S.
Dr. Scott Gottlieb is a CNBC contributor, a resident fellow at the American Enterprise Institute, Pfizer board member and the former commissioner of the FDA.
Even though there's a lot that we don't know about the novel coronavirus that's burning its ways through China, there are some critical assumptions we should make about its continued spread.
First, the epidemic in China is likely much broader than official statistics currently suggest. A lot of mild cases probably remain unrecognized. Even a lot of severe cases are unreported since diagnostic tests were only recently deployed to the front lines of China's healthcare system.
Second, global spread appears inevitable. So too are the emergence of outbreaks in the U.S., even if a widespread American epidemic can still be averted. When pockets of the outbreak arrive on our shores, we shouldn't have undue panic. But we need to be ready.
The most important public health measures to contain new outbreaks are the early identification and isolation of cases to prevent further spread. Key to applying these measures and limiting spread will be easy access to reliable and rapid diagnostic tests to enable widespread screening. These tools will allow us to identify new cases early and isolate sick individuals.
Right now, the Centers for Disease Control and Prevention has a test that works by detecting parts of the virus' genome in the blood. CDC is working with the Food and Drug Administration to make this type of test more widely available to public health labs throughout the U.S. The agencies are working to advance the test under an authorization for emergency use. This is a regulatory designation that accelerates the normal FDA clearance process during public health emergencies.
The CDC test is fast. It can diagnose a sample in a few hours once a blood specimen reaches a designated lab. The test is likely to be given primarily to state and local public health laboratories. But to adopt more widespread surveillance and diagnosis, we may need a diagnostic that's more readily accessible to providers on the front line of response. This includes tests that can be used right in the doctor's office, clinics, and hospitals – or even at ports of entry.
Since the CDC's test requires samples to be sent to a reference lab, screening is largely a clinically driven decision. So, who gets screened is based on an individual's symptoms and their travel history. Only more severe cases that are most likely to have coronavirus are being tested. This approach will work well when the numbers of infected people are low. But if we have wider outbreaks in American cities, then containing further spread will require wider screening.
We need to adapt technologies that can allow testing right at the point of care. These kinds of rapid diagnostics exist for diseases like influenza. In the case of flu, a nasal swab is used to make a rapid diagnosis in the doctor's office, where the strip test offers physicians a readable output.
These same technologies can be tailored to coronavirus. One approach is based on the use of antibodies that adhere to parts of the virus that contribute to its symptoms called antigens. If virus is present, the antibodies bind to these viral antigens and produce a chemical reaction that signals the presence of an infection.Once a coronavirus is identified in a sick patient, doctors could then rely on more sophisticated tests done in public health and reference labs to confirm whether it's the Wuhan strain.
Another approach, using platforms like GeneXpert, can rapidly amplify and detect specific parts of viral RNA. These tests are based on a self-contained machine that's widely used to test for things like hepatitis C. It was also used to screen for Ebola virus. Bringing more of these capabilities to the point of care can improve surveillance and diagnosis.
Accurate diagnostics are key to enabling successful public health measures. They allow us to identify and isolate patients and allocate scarce medical resources for isolation and treatment.
FDA would need to specifically authorize the adoption of such tests at the point of care, rather than only allow their use in sophisticated labs. In the setting of a wider outbreak public health workers won't be able to broaden testing without diagnostics that can be deployed in the field.
Given past experience, we know that the public health labs performing the more sophisticated DNA tests that CDC is aiming to deploy will quickly become overwhelmed in the setting of multiple outbreaks here in the U.S. In that case, to prevent wider spread, what may be most needed are simple, reliable tests that let us screen more widely for the spread of this novel virus.