Feb. 20 (UPI) -- As many as 30 countries have instituted some form of travel restriction in response to the new coronavirus, COVID-19, World Health Organization officials said Thursday, in spite of limited scientific evidence indicating that they work in containing the spread of infectious diseases.
According to Jaouad Mahjour, acting WHO Regional Director for the Eastern Mediterranean, the measures instituted in these countries have varied from the effective "lockdown" on Wuhan, China -- the city at the center of the outbreak -- imposed in January to the decision by the United States to deny entry to foreign nationals who have visited China in the 14 days prior to their arrival
"The U.S. is doing anything possible to try and limit the number of COVID-19 infections coming into the country, and if we believe it may be arriving, then using travel restrictions can possibly delay arrival to allow us time to prepare is key," Brandon Brown, associate professor of social medicine, population and public health at the University of California-Riverside School of Medicine, told UPI.
Officials at both the U.S. Centers for Disease Control and Prevention and the WHO, and their counterparts in several nations, have said the intention was exactly that -- to allow time to prepare.
Earlier this week, Sylvie Briand, director of infectious hazards management for WHO, credited the containment measures taken in Wuhan for delaying spread of COVID-19 to other parts of China by two to three days, and slowing the spread to other countries by at least two weeks.
Restrictions may slow spread
In a paper scheduled for publication in the CDC's Emerging Infectious Diseases in May, but released this week, the authors noted there is "limited evidence" that measures such as border closures would contain or control a flu pandemic.
But researchers did find some studies supporting the use of travel restrictions to "delay the start of local transmission and slow international spread."
In addition, they concluded that there is "no available evidence" indicating that screening of travelers "would have a substantial effect on preventing" the spread of the flu.
"The few studies included in the paper are the best evidence we have at this time, and if there is a possible benefit of travel restrictions we should utilize them in our prevention toolkit," said Brown, who has not involved in the EID review. "Although the ban delayed the spread within and outside China, we also need to make sure that people at the center of the outbreak have the resources -- food, water, power, medical care, prevention tools -- they need."
Additional interventions needed
The WHO wrote on Wednesday that modeling assessments designed to estimate the impact of the Wuhan travel ban on reducing transmission both inside and outside of China concluded that the measures are "projected to have only a modest effect on the progression of the outbreak."
To maximize their effectiveness, per the report, the measures would need to be combined with other public health interventions, including early case isolation, social distancing and population-level behavioral changes.
WHO director-general Tedros Adhanom Ghebreyesus has consistently urged countries considering travel restrictions to "balance" the health rationale for the measures against human rights considerations.
In a briefing from U.S. President Donald Trump's COVID-19 Task Force on February 7, CDC director Robert Redfield noted that the travel restrictions imposed by the administration were part of a layered response centered around early case recognition, isolation and contact tracing to prevent further spread "using effective and proven public health measures."
Nancy Messonnier, of the agency's National Center for Immunization and Respiratory Diseases, on February 14, also said the measures were intended to "slow the introduction and impact" of COVID-19 in the United States.
Have they helped?
To date, the U.S. has reported 15 confirmed cases of the virus, not including those among the passengers evacuated from the Diamond Princess cruise ship earlier this week. All of the confirmed cases have been quarantined, either in hospitals or in military facilities.
While cases have been found in 26 countries, spread of the virus is thought to have been slowed. Compared to the nearly 75,000 cases in China, there have been just over 1,000 in the rest of the world.
"The logistics of outbreak response are complicated and can only be managed by integrating local, state, and federal agencies, including hospitals, public health systems, government and academia," Brown said. "For the current situation with COVID-19, with the vast majority of cases and deaths limited to mainland China, I do agree with the travel restrictions and traveler screening currently taking place to protect us."