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Faculty Viewpoints

Coronavirus Update: How Far Has the Virus Spread and What’s Next?

In the last few weeks, Professor Howard Forman’s Twitter feed (@thehowie) and his other public communications have become a valuable source of information and expertise related to the COVID-19 outbreak in the United States. He says that greatly increased testing capacity is key to unlocking greater understanding of the disease and learning how to slow its spread.

Coronavirus emerging from the surface of a cell.


  • Howard P. Forman
    Professor of Radiology and Biomedical Imaging, Economics, Public Health, and Management; Co-founder, Pozen-Commonwealth Fund Fellowship in Health Equity Leadership, MD/MBA Program, and MBA for Executives Program

There are small, but meaningful, pockets of wide community spread, making local mitigation a logical priority over complete containment and, perhaps, the only logistical opportunity. Through much of the rest of the country there is still a relatively low prevalence of documented disease. We do not know whether this is due to under-testing (likely, but not certain) or whether spread is being limited and active containment measures (active testing, tracing of contacts, cancellation of public events, social distancing, etc.) can keep it in check.

“Once adequate testing is here, we can do surveillance of broader populations to answer key questions: How readily does the disease spread? What percent are asymptomatic? Are asymptomatic carriers shedding virus?” 

The U.S. has not started to do even minimally appropriate testing: there is a vast shortage of capacity. Last weekend, we were told that this was about to change. It did NOT. We are again told that testing will begin to grow significantly: we know, for instance, that the last four states without any in-state testing are now online as of Friday evening. We are told that two large private companies will be providing testing beginning on Monday, March 9. Some academic medical center/university labs are either already open or about to open. Still, we do not expect to be at full testing capacity until the latter part of next week or later. We should expect the number of documented cases to grow significantly, even as we know that some regions (King County, Washington) have discouraged testing of presumed cases.

Once adequate testing of potential COVID-19 patients is here, we then can do some surveillance of broader populations to answer key questions: How readily does the disease spread? What percent are asymptomatic? Are asymptomatic carriers shedding virus? When? We would like to know whether children are infected at the same rate as adults (even as they appear relatively unaffected). Are they transmitting infection for as long as adults and, thus, a source of further infection in the community? What factors account for differing severities of illness observed? 

Answers to the above questions will help inform private and public decisions about closings of public entities (schools, in particular) and businesses, and guide further testing. Better understanding the disease will also allow us to protect the most vulnerable populations. Elderly and immunocompromised people are at great risk. Healthier and younger individuals have an obligation to protect not just themselves, but those at greatest risk. 

Follow Howard Forman on Twitter.

Department: Faculty Viewpoints