Commonsense Coronavirus: Expert Explains Containment

HUDSON VALLEY, NY — With 421 cases of the new coronavirus confirmed in New York as of midday Friday — 158 of them in Westchester County — Patch returned to an expert to talk about the meaning of efforts by state health officials to fight the virus officially known as COVID-19.

Dr. Robert W. Amler is a dean at New York Medical College, heading the School of Health Sciences and Practice, and is also vice president for government affairs at the campus in Valhalla. Formerly he was chief medical officer at the federal Centers for Disease Control and Prevention's Agency for Toxic Substances and Disease Registry. See his earlier interview with Patch: Expert Offers Common-Sense Reasons Not To Panic Over Coronavirus.

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Patch: Are there still commonsense reasons not to panic?

Amler: Yes. For the vast majority of Americans the risk of infection is still low, and for those infected the risk of serious illness is low.

Also on the positive side we are testing many many more people now with a much broader availability of tests. So, we'll have better ascertainment of the whole picture of the virus — what it does, who it affects the most, what's the incubation period, how long are you contagious, what happens to people when the virus affects them. The second great benefit is if we identify more cases more quickly we can make sure they are quarantined and their friends and neighbors and loved ones are less likely to be accidentally exposed. It's a great benefit, knowing someone is positive.

Q: What's the difference between slowing the rate of infection and stopping the outbreak?

A: Imagine your car going down the Saw Mill Parkway and you realize you're going too fast. You can't just stop on a dime, maybe you don't even possess the kind of brakes that allow you to get to zero flat. In outbreaks you sometimes get to a stage where things are happening so much and there's so much transmission you can't stamp it all out, but you can put the brakes on and slow it down.

That's what mitigation is. Mitigation doesn't guarantee that the efforts are going to stop the virus in its track. But by slowing the virus we reduce the number of people getting sick, we reduce the number of people in the ICU on ventilators.

We do the same with influenza. We want to stop transmission at every possible chance but also to mitigate the overall transmission in the community.

Q: What is a cluster?

Amler: We would consider a cluster of cases to be any verified group of cases that occur within a circumscribed geographic area, or circumscribed time period, or circumscribed group of people.
Clusters occur in nature. and sometimes clusters occur because of some common source.

Q: The outbreak in New Rochelle, New York meets all three of those criteria. So what do public health officials do with a cluster?

Part of the response is the usual case-by-case person-by-person investigation, which is really what we've been doing across the country. Then you have a broader strategic response across the cluster: Who gave it to whom, and so forth. What is going on in that group and how can we interrupt exposure?

Q: Why make a 1-mile containment zone as has been done in New Rochelle?

A: Typically you try to draw a reasonable boundary around what you think is the epicenter of the outbreak. You can't know exactly what the zone of risk is geographically, so in a typical situation like this you want to err on the side of being a little wider to have some assurance that you have not missed anything.

It's just like the six-foot rule of staying away from sick people. Are you less protected when you're 5 feet 11 inches away? That's not the case, you're just trying to have a benchmark, something people can work with.

Q: Since people are free to travel in and out of the containment zone, couldn't someone who is contagious just carry the virus elsewhere?

A: It's not meant to be an onerous restriction. What they're containing is the large group gatherings, because we saw evidence that previous large group gatherings there accounted for so many of the cases that were popping up.

The people themselves, for the ones who are not under quarantine, their movement is not restricted, unless they want to go into a large group gathering in that area, that's what the state is saying right now.

Q: What about the presence of the New York State National Guard?

A: I think the presence of the National Guard runs the risk of alarming people. We've seen so many disaster movies. It's my understanding that the role of the Guard is to make sure that there's a stringent cleaning activity in place and make sure that people have enough food.

Q: What's the use of testing for people who had the new coronavirus and recovered?

A: It's less useful for the containment zone but very useful for our understanding of the pattern of this virus. For example, we might find the virus has been around longer than we think and has not caused much damage ... that something happened this season to change things. Or we might find that this is truly an emerging virus.

Q: Much of the outbreak in New York was initially connected to one New Rochelle resident. Is he a "patient zero?"

A: Many times we call it an index case. There's no question that once you get a very sick person in the community it triggers a lot of investigation to find out what's going on. He presumably got it from someone who was in that area or who passed through.

It's more common that people who are early cases in an investigation can't tell you where they got it.

Coronavirus in New York and Beyond

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• Coronavirus In New Rochelle: Life At The Epicenter