By Andrew Iliff, HGHI | March 6, 2020
Public health departments across the country are scaling up the crucial work of testing thousands of Americans for the coronavirus that causes COVID-19. The process, essential in an outbreak, has been delayed by a CDC error in the first set of tests made available,budget cuts, and restrictions on who qualified for testing. As a result, numbers may spike up significantly over the next week, and lead to fear and more questions. HGHI Faculty Director Dr. Ashish Jha explains the situation, and what to expect.
“Right now, we have more than 250 identified cases. But there are probably a couple of thousand Americans with coronavirus infection right now. We just don’t know about it because we haven’t been testing those people. They not only have the infection, they’re also spreading it to others.
“As testing ramps up, we will start identifying all those people. And the reaction is going to be, Oh my God, the infection is spreading in massive numbers!
“And the answer is: No, that’s not what the data tell us. The data is going to tell us that we are finally identifying people. So, I worry about the panic that is going to ensue when large numbers of people start getting identified.
The thing to understand is, those people are already here and they’re already infected. Identification is the first part of the strategy of containment. It’s going to be particularly important for public health leaders to speak in terms that offer people assurance. Not understating the importance of this, but reminding people that these are not new cases. “
Why testing matters
Increased testing is beginning to show that there already are clusters of coronavirus infections across the United States. While this is a concerning discovery, understanding these patterns of how the virus spreads is crucial to mitigating the outbreak. Here is why testing is such an important part of an epidemic response:
It tells us where the virus is, and where it is spreading
It gives us a better sense, for example, if the virus is only spreading from known cases, or showing up unexpectedly without knowledge of the source (so-called community transmission)
It allows us to sequence the genome of the virus, with which we can then trace the origin of a specific strain. For example, a patient in Seattle had been infected with a coronavirus also found in earlier cases in Europe
Taken together, these data points inform what protection and prevention measures are appropriate for each community.