ALBANY – New York, New Jersey and Connecticut added travelers from California, Tennessee and six other states to its quarantine list Tuesday morning, pushing the total to 16 states representing 48% of the U.S. population.
Georgia, Iowa, Idaho, Louisiana, Mississippi and Nevada were also put on the quarantine list.
Travelers from the affected states will now have to isolate for 14 days upon arriving in the three northeastern states, doubling the original list of eight states included in the joint travel advisory issued last week.
"We've set metrics for community spread just as we've set metrics for everything the state does to fight COVID-19, and eight more states have reached the level of spread required to qualify for New York's travel advisory," New York Gov. Andrew Cuomo said in a statement.
New Jersey, New York and Connecticut are all requiring travelers from states with high COVID-19 infection rates to quarantine for two weeks unless they are passing through for a short period of time, such as a flight layover.
Essential workers are also exempt, with New York offering separate guidance on precautions they should take in lieu of a full quarantine.
The order includes residents of one of the three states who travel to a high-COVID area and return home.
Quarantine order applies to high-COVID states
All three states are following the same criteria: Anyone coming from a state with at least 10 positive COVID-19 cases per 100,000 residents or a 10% positive testing rate on a seven-day rolling average is included.
Enforcement, however, varies from state to state, with New York taking a hardline approach that includes monitoring flight logs and asking travelers to fill out questionnaires on airplanes.
The complete list
The new additions mark a stark new chapter for the quarantine order.
They include the state of California, the most populous state with more than 39 million people. Georgia, meanwhile, is home to Hartsfield-Jackson Atlanta airport, the busiest in the nation.
On Friday, California Gov. Gavin Newsom said he respected the decision-making authority of the New York, New Jersey and Connecticut governors. At the time, it had become clear California had met the threshold to be included on the quarantine list.
"I am not here to judge the actions of other governors," Newsom said.
Welcome to New York, now fill out this questionnaire: New York asking airline passengers to fill out health form as part of COVID-19 quarantine
New states match data analysis
The newly added states matched a USA TODAY Network New York analysis of COVID-19 data, which showed they all surpassed 10 positive cases per 100,000 residents in the past 10 days.
Two of those states, Louisiana and Mississippi, seemed to benefit from technical glitches or corrections that excluded them from the original list.
On June 21, Louisiana's rolling seven-day average was 9.7 positive cases per 100,000 residents.
But that calculation included zero new cases on June 19, when the Louisiana Department of Health removed more than 1,600 duplicate positives, which made the state's cumulative case total fall that day and threw off the seven-day average.
Mississippi, meanwhile, showed only 5.4 positive cases per 100,000 residents for the week that ended June 21. That number was clearly suppressed: Technical issues had prevented Mississippi state officials from updating their daily case total for the four days prior.
New York, New Jersey and Connecticut have worked together on some major COVID-19 decisions, including beach openings in late May, reasoning that there is a high amount of travel among the states that make up the tri-state area.
Massachusetts, another neighboring state, has a more broad-reaching travel advisory in effect, requesting that any traveler to the state (or resident returning home) quarantine for 14 days upon arrival.
On Tuesday, Massachusetts Gov. Charlie Baker eased that advisory, allowing travelers from Rhode Island, Connecticut, Vermont, New Hampshire, Maine, New York and New Jersey to enter without a quarantine beginning July 1.
Jon Campbell is a New York state government reporter for the USA TODAY Network. He can be reached at JCAMPBELL1@Gannett.com or on Twitter at @JonCampbellGAN.
This article originally appeared on New York State Team: NY quarantine order adds 8 states: California, Georgia, Tennessee