Our knowledge of the disease will help us with tools and policies. There are a number of key things we still don’t understand. A number of studies are being done to answer these questions, including one in Seattle done with the University of Washington. The global collaboration on these issues is impressive and we should know a lot more by the summer.
Is the disease seasonal or weather dependent? Almost all respiratory viruses (a group that includes COVID-19) are seasonal. This would mean there are fewer infections in the summer, which might lull us into complacency when the fall comes. This is a matter of degree. Because we see the novel coronavirus spreading in Australia and other places in the Southern hemisphere, where the seasons are the opposite of ours, we already know the virus is not as seasonal as influenza is.
How many people who never get symptoms have enough of the virus to infect others?What about people who are recovered and have some residual virus—how infectious are they? Computer models show that if there are a lot of people who are asymptomatic but infectious, it is much harder to open up without a resurgence in cases. There is a lot of disagreement about how much infection comes from these sources, but we do know that many people with the virus don’t report symptoms, and some portion of those might end up transmitting it.
Why do young people have a lower risk of becoming seriously ill when they get infected? Understanding the dynamics here will help us weigh the risks of opening schools. It is a complicated subject because even if young people don’t get sick as often, they might still spread the disease to others.
What symptoms indicate you should get tested? Some countries are taking the temperature of lots of people as an initial screening tool. If doing this helps us find more potential cases, we could use it at airports and large gatherings. We need to target the tests we have at the people at greatest risk since we don’t have enough tests for everyone.
Which activities cause the most risk of infection? People ask me questions about avoiding prepared food or door knobs or public toilets so they can minimize their risk. I wish I knew what to tell them. Judgements will have to be made about different kinds of gatherings like classes or church going and whether some kind of spacing should be required. In places without good sanitation, there may be spread from fecal contamination since people who are infected shed the virus.
Who is most susceptible to the disease? We know that older people are at much greater risk of both severe illness and death. Understanding how gender, race, and co-morbidities affect this is a work in progress.
