This is part of our Coronavirus Update series in which Harvard specialists in epidemiology, infectious disease, economics, politics, and other disciplines offer insights into what the latest developments in the COVID-19 outbreak may bring.
Cases of the new coronavirus that originated in the Chinese city of Wuhan have expanded into the thousands, with more than 170 deaths. The virus’ spread elsewhere — including the U.S., which has at least six confirmed cases, the last one marking the first time the illness was spread from one person to another here — contributed to the World Health Organization’s decision to declare the outbreak a public health emergency. The Gazette spoke to Professor of Epidemiology Marc Lipsitch, director of the Harvard T.H. Chan School of Public Health’s Center for Communicable Disease Dynamics and an expert on the spread of infectious diseases, including his work during the SARS coronavirus outbreak in 2003.
GAZETTE: The Centers for Disease Control and Prevention has identified a handful of coronavirus cases in the nation and is investigating others. How worried should residents be?
LIPSITCH: At this point, worry won’t accomplish anything and doesn’t help. It is reasonably likely that there will be more cases in the United States, but whether that means double digits or many more still remains to be seen. I do think it may be more challenging to control than SARS, because it seems that a lot of cases are relatively mild, which makes them harder to identify.
GAZETTE: It’s a coronavirus, which includes not only SARS but things like the common cold. Does this mean, when the symptoms are mild, that it’s easy to get it mixed up with something like a cold or the flu?
LIPSITCH: It seems that way. Some of the symptoms are more severe than colds or than typical flu, but not everybody has a severe infection. So the milder infections can certainly be missed.
GAZETTE: One thing that struck me watching this unfold is the rapid expansion in China. Is that because it’s more infectious than we had thought, or is it because now that we’re looking for it all these mild cases are turning up?
LIPSITCH: I think it’s a mix of things. I think responsible people weren’t saying how infectious it was until recently. The most optimistic scenario — that it’s acquired from animals and then transmitted among humans only very modestly — is no longer credible. Each day it seems clearer that transmission is relatively common — estimates are converging around something similar to SARS. Reporting has been very irregular, so the big jumps in case numbers don’t necessarily mean new cases, just newly reported cases. We should remember that it’s only been about a month since the problem was recognized. The fact that we’re able to test and confirm cases of a completely unknown virus is amazing and a testament to very, very good biological work being done very quickly.