Experts say travel restrictions implemented by states are more difficult to enforce than limits placed on travelers from other countries. Getty Images
  • New York, New Jersey, and Connecticut are instituting 14-day quarantines on travelers coming from COVID-19 hot spots.
  • Experts say quarantines and travel bans can help delay and even perhaps reduce COVID-19 transmission, but they can’t prevent the spread of the disease.
  • They note that state restrictions are more difficult to enforce than limits placed on travelers from other countries.

COVID-19 cases are still on the rise in the United States, with the pandemic surging in many states in the South and West after the initial outbreaks in major cities such as New York and New Orleans. 

That dynamic has prompted New York, New Jersey, and Connecticut to put mandatory 14-day quarantines in place for any traveler coming to these states from known pandemic hot spots to prevent a resurgence of the virus.

That’s not the first time a state has implemented aggressive measures on travelers coming from other states. 

In late March, when New York’s COVID-19 outbreak was reaching its peak, Rhode Island Gov. Gina Raimondo called for a National Guard–enforced 14-day quarantine on all travelers coming from New York.

At the time, this prompted New York Gov. Andrew Cuomo to threaten to sue the state, calling the quarantine measures “a point of absurdity.” 

How travel bans do — and don’t — work

Amid all this back-and-forth, the basic question remains: Do these types of interstate travel restrictions even work? 

Experts aren’t so sure.

“The literature is split and the data is incomplete,” said Patrick Hardy, a certified emergency manager, risk manager, and FEMA Master of Exercise Practitioner.

“Most early studies of travel restrictions involving COVID are from February and March with different predictions on the effectiveness of future bans. However, one academic paper published in a major journal studied the China to Australia ban, which was enacted on February 1. In that study, they determined that the ban lowered the number of cases by a whopping 86 percent,” Hardy said.

Most experts agree that outright travel bans — such as closing borders to international travelers — can help buy time to manage the disease, but the prohibitions aren’t likely to stop the spread entirely in countries where the disease is already present. 

“Most of the data on the effectiveness of travel restrictions are in the form of mathematical modeling,” Dr. Mahalia S. Desruisseaux, an infectious disease specialist and associate professor at the Yale University School of Medicine in Connecticut, told Healthline.

“Based on those models, travel bans would succeed in temporarily delaying, not reducing, viral spread. Recent predictive models published show that a 90 percent international travel restriction would delay international spread of the virus by no more than 2 weeks. Less restrictive travel bans would result in even shorter delays,” Desruisseaux said.

Countries such as New Zealand and Vietnam, which have been effective in clamping down on COVID-19 spread and deaths, both employed travel bans and mandatory quarantines as part of their toolkit of pandemic response. 

These measures were effective, in part, because they came early — Vietnam closed its borders to China in February — and worked in concert with a unified national public health response and countrywide lockdowns.

Speed and decisiveness are key, says Dr. Richard Martinello, medical director of infection prevention for the Yale-New Haven Health System in Connecticut.

“Travel bans, whether they be between states or countries, can slow the spread of a disease from areas of high infection rates to areas with low infection rates if the people are compliant with the ban and the ban comprehensively targets travel from areas of high spread,” he told Healthline.

“With a highly transmissible respiratory tract infection such as COVID, a travel ban imposed later may slow but will not stop the spread of the virus,” Martinello said.

State restrictions face challenges 

Perhaps the biggest hurdle facing states like New York and New Jersey trying to enforce mandatory quarantines is their ability to actually enforce such measures. 

“Data on the effectiveness of travel bans is sparse in the United States, but a recent announcement from Singapore sheds some light on the challenge,” Shaun Barry, a global leader for contact tracing at business analytics firm SAS, told Healthline.

“Singapore is widely known for its strict enforcement of health laws, including travel restrictions and stay-at-home orders,” he explained. “Even with this reputation, the Singapore government announced that it has revoked work passes for 140 people for violating travel restrictions. That volume is telling: People who were well informed about travel restrictions risked their jobs by traveling in a country that is only 31 miles wide.” 

“Translate that to the U.S. — but with no enforcement, 100 times the size, and thousands of roads that cross state borders — and it’s easy to conclude that travel bans are more symbolic than effective,” Barry said. 

And, unlike Singapore, states are limited in their enforcement options. 

In New York, New Jersey, and Connecticut, for example, people who don’t voluntarily quarantine will be subject to a $2,000 fine for the first offense, $5,000 for the second, and up to $10,000 if it can be proved that they “caused harm.” 

Those disincentives — and how readily people moving from COVID-19 hot spots to these states can be tracked down — may prove insufficient to do much to prevent a resurgence of the virus. 

Instead, “what these bans do is create a false sense of security and delay other effective measures of mitigating spread,” Desruisseaux said.  

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