Yale study: Connecticut’s first coronavirus cases have roots in Washington state, not foreign countries
[Edited for brevity]
A new study by researchers at the Yale School of Public Health shows that the vast majority of Connecticut’s first coronavirus cases have roots in Washington state, and that the danger of domestic travel has exceeded the danger of international travel since early- or mid-March.
“There’s so much transmission happening within the United States now that we really need to focus on what is happening within our own borders,” said lead researcher Nathan Grubaugh.
The study does not challenge the initial origin of the coronavirus — which is believed to have originated in Wuhan, China — but rather the virus’ route to Connecticut.
The study also
points to a need for local responses to the virus, as opposed to international travel bans or restrictions. While officials were focused on monitoring international travel, the study suggests it was actually domestic travel that brought the virus to the state.
The researchers, led by Grubaugh, looked at the genetic code of the viruses in nine of Connecticut’s first cases. They then constructed what Grubaugh said is essentially a family tree, backtrack the viruses’ lineage.
Grubaugh said
he and his team found that seven of the nine cases were “very similar” to viruses sequenced in Washington state. Although there’s some data still missing at this point, Grubaugh said it appears that the virus didn’t travel directly from Washington state, but instead first spread to states such as Massachusetts, Michigan, Ohio and Pennsylvania, before journeying into Connecticut.
Grubaugh’s team looked at travelers flying into Bradley, Boston Logan and John F. Kennedy airports, from five hot-spot countries and five hot-spot states. With that data, tempered by how accurately those hot spots were measuring their own outbreaks, the researchers created a “risk estimate” for how many infected people could have been flying into Connecticut.
And they found that, by early- to mid-March, “the risk shifted from international importations to domestic,” Grubaugh said. The research team believes that shift would be even more apparent if they had also accounted for train and car travel.
In follow-up studies, the researchers are looking at more recent coronavirus cases. So far, Grubaugh said, many of those cases appear to have roots in New York state.
“Now we’re seeing new ones that look to be introductions coming from New York,” Grubaugh said. “We’re getting that spillover coming in.”
The study’s implications bolster the argument for a domestic — not international — response to the coronavirus.
“We really need to focus on local surveillance and testing and isolating patients who are infected,” he said. “It needs to be a localized response."
This story has been updated.
Author: Emily Brindley can be reached at ebrindley@courant.com.
