The Harvard Gazette spoke with Marc Lipsitch an epidemiologist and head of the Harvard T.H. Chan School of Public Health’s Center for Communicable Disease Dynamics, about the course of the epidemic, including the still-unresolved question of its effect on children.
GAZETTE: You’ve been quoted you as saying you expect between 40 percent and 70 percent of humanity to be infected with this virus within a year. Is that still the case?
LIPSITCH: It is, but an important qualifier is that I expect 40 to 70 percent of adults to be infected. We just don’t understand whether children are getting infected at low rates or just not showing very strong symptoms. So I don’t want to make assumptions about children until we know more. That number also assumes that we don’t put in place effective, long-term countermeasures, like social distancing for months at a time which, I think, is a fair assumption. It may be that a few places like China can sustain it, but even China is beginning to let up.
GAZETTE: You mentioned children having been hit only lightly by this. What about other parts of the population? What do we know about the impact of this from a demographic standpoint?
LIPSITCH: It’s definitely the case that the older you are, the more at risk of getting infected you are and, if you get symptomatic infection, the more at risk of dying you are. Men also seem to be overrepresented among those getting severe illness. The reasons why are a really important research question. One thing that also needs to be looked at is the impact on health-care workers because they are at high risk of getting infected, and I would like to know whether they’re at higher risk of getting severe infection. Some of the anecdotal cases of young physicians dying make me wonder whether they’re exposed to a higher dose and that’s making them sicker.
GAZETTE: What’s the most important unanswered question to your mind?
LIPSITCH: One of the most important unanswered questions is what role do children play in transmission? The go-to intervention in flu pandemic planning is closing schools, and that may be very effective or it may be totally ineffective. It’s a costly and disruptive thing to do, especially in the United States, because many people rely on school breakfast and lunch for nutrition. So we really need evidence that closing schools would help. We need detailed studies in households of children who are exposed to an infected person. We need to find out if the children get infected, if they shed virus, and if that virus is infectious. The second issue that we should be trying to get ahead of is the extent of infection in communities and in places that aren’t doing extensive testing.
GAZETTE: What do we know about for sure about how children are affected by this virus?
LIPSITCH: We know that the cases of children sick enough to get tested is much lower per capita than those of adults. And we also know that, in China outside of Hubei province, the difference between children and adults is smaller. Children are still underrepresented, but they’re a larger part of the total than inside Hubei province. That would suggest that part of the equation is that they are getting infected but they’re not that sick — it’s easier to identify less-severe cases in a system that’s not overwhelmed as it is in Hubei. But we don’t know whether they’re infected and not as sick or whether there are a lot of kids that aren’t getting infected even when they’re exposed.
Header: An adult and child wear flu masks in Manila, Philippines. AP photo.