Epidemic Experts Say "Cluster Zones" Imperfect But An Experiment Worth Trying

Public health interventions are almost always trial and error, and with hotspots around the city approaching a six-fold increase in the infection rate over the past month, epidemiologists say Governor Andrew Cuomo’s experiment in micro-targeting cluster zones is worth trying.

“The state’s plan makes sense,” said Dr. Jessica Justman, an epidemiologist and infectious disease specialist at Columbia University’s Mailman School of Public Health. “I understand it will be confusing to some to implement, but that’s because we’re not used to this kind of geographically tailored COVID plan.”

Under the plan, the state is re-imposing some of the stringent rules from earlier in the pandemic to six areas across the state, including two in Brooklyn and one in Queens. Within each area, there are three concentric circles, each with varying levels of restrictions on activities such as gathering indoors and outdoors, dining in restaurants, and attending school in-person.

Experts say success is far from guaranteed, especially given the pushback from many local residents in the affected areas. But the consensus among epidemiologists contacted by Gothamist is that the state’s plan—which was developed in consultation with experts such as Dr. Thomas Frieden, a former city health commissioner and a former director of the Centers for Disease Control and Prevention—represents a measured response to an emerging problem, striking a balance between doing too much and too little.

“The other thing would be to move to a stay-at-home situation, like we did in March, which we absolutely know works,” said Dr. Denis Nash, a former epidemiologist at the city Health Department and the Centers for Disease Control and Prevention, who teaches at the CUNY Graduate School of Public Health.

“That's not what anyone wants for any neighborhood,” he said. But extreme lockdowns remain an option if coronavirus spread continues to escalate and gets out of control, because, “that is what we know is most effective at getting the reproductive number down to a place where it can be controlled again.”

The reproductive number—sometimes called R0 or Rt—is a way of measuring the rate of transmission. For a pathogen to spread, each infected person needs to transmit it to more than one other person or it will eventually die out. If people are quickly isolated after being diagnosed, an infectious disease will eventually have nowhere to go.

Nash said Cuomo’s “cluster zone” approach will be far from perfect at containing the coronavirus, because people are allowed to move freely in and out of the zones.

“You can use zip code borders or other borders to think about where the intervention needs to be targeted, but at the end of the day, the virus really doesn't recognize any borders—it goes where it wants,” Nash said. “If people are moving back and forth, we have to expect that the virus is going to do the same, so I'm a little worried these measures are not going to contain the spread as much as we would hope.”

Nash says he would be more optimistic if there were a quick and dramatic reduction in gathering sizes in these areas.

“We don’t have a lot of direct data, which is unfortunate, but there's a presumption that I think is reasonable... that a lot of [the spreading] has to do with mass gatherings, and so I think the focus on reducing those is a good idea,” he said.

Dr. Stephen Morse, who’s also an epidemiologist and infectious disease specialist at Columbia University’s Mailman School of Public Health, is far more critical of the plan. He is concerned that Cuomo’s restrictions will only work on paper and will provoke unquellable civil unrest.

“I don’t know how you can realistically enforce this,” Morse said. “Those resisting feel they’re being discriminated against, and others in the same zones who are following recommended precautions will feel similarly, for different reasons. It’s a pity it came to this. I hope it achieves the intended effect of preventing spread in these communities, but I’m not optimistic.”

The last three nights, which have coincided with the eight-day fall harvest festival of Sukkot — a sort of holy Oktoberfest for observant Jews — have seen anti-government demonstrations that at times have turned violent.

Morse said there needs to be greater outreach to community leaders — something city and state leaders say they’ve done repeatedly over the past several weeks, but to little avail. Nonetheless, he said, they need to keep trying.

“It’s reminiscent of the measles outbreak [last year] in these same places, though at least then there was a vaccine,” he said. “Here, with not even a vaccine, we have fewer and blunter instruments to work with.”

Dr. Lorna Thorpe, a former CDC and city Health Department epidemiologist now at NYU, agreed that authorities need to find “champions and credible voices in these neighborhoods to help build trust.” She also said enforcement efforts, even as they single out specific geographic areas, have to carefully avoid being discriminatory.

“I think it’s critical to target these neighborhoods and be consistent across all schools and places of worship,” Thorpe said —adding that to do this effectively, the Cuomo and de Blasio administrations will need to work better together.

“Most of all the public needs to see coordination between city and state” Thorpe said.