Scheduled airline traffic around the world – Credit Wikipedia
First the CDC statement, after which I'll return more on the checkered history of interdicting diseases at ports of entry.
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While reassuring the public that the current risk to Americans from the Ebola outbreak in the DRC is `low', yesterday the CDC announced enhanced screening of travelers and imposed `Entry restrictions on non-US passport holders' if they have visited Uganda, DRC, or South Sudan in the past 3 weeks.This invocation of Title 42, and a de facto `travel ban' for non-US passport holders is noticeably more restrictive than what we saw during the 2014-2015 Ebola outbreak in West Africa (see CDC Statement On Airport Screening Of Arrivals From West Africa).
First the CDC statement, after which I'll return more on the checkered history of interdicting diseases at ports of entry.
CDC Statement on the Use of Public Health Travel Restrictions to Prevent the Introduction of Ebola Disease into the United States
For Everyone
May 18, 2026
What to know
On May 18, 2026, CDC, DHS, and other appropriate federal agencies implemented enhanced travel screening, entry restrictions, and public health measures to prevent Ebola disease from entering the United States amid ongoing outbreaks in East and Central Africa.
Statement on Title 42 Order
Title 42 Order
Title 42 Order Suspending the Right to Introduce Certain Persons from Countries Where a Quarantinable Communicable Disease Exists
The Centers for Disease Control and Prevention (CDC), and the Department of Homeland Security (DHS), and other appropriate federal agencies, are taking proactive measures to protect the health and safety of the American public in response to ongoing Ebola Virus Disease (EVD) outbreaks.
Under authority granted by Sections 362 and 365 of the Public Health Service (PHS) Act, 42 U.S.C. §§ 265, 268, and their implementing regulations, CDC is implementing targeted public health measures intended to reduce the risk of Ebola disease caused by the Bundibugyo virus (EVD) by preventing its introduction into the United States. These actions are based on current epidemiological evidence, ongoing risk assessments, and the highly serious nature of EVD. This order will be in effect for 30 days, effective immediately.
Effective immediately, CDC will:At this time, CDC assesses the immediate risk to the general U.S. public as low, but we will continue to evaluate the evolving situation and may adjust public health measures as additional information becomes available.
- Enhance public health screening and traveler monitoring for individuals arriving from areas affected by Ebola outbreaks in the region.
- Entry restrictions on non-US passport holders if they have been in Uganda, DRC, or South Sudan in the previous 21 days.
- Coordinate with airlines, international partners, and port-of-entry officials to identify and manage travelers who may have been exposed to Ebola virus.
- Enhance port health protection response activities, contact tracing, laboratory testing capacity, and hospital readiness nationwide.
- Continue deployment of CDC personnel to support outbreak containment efforts in affected regions.
If you have traveled through the affected countries you are encouraged to monitor CDC travel health notices and seek medical attention immediately if you develop symptoms consistent with Ebola, including fever, weakness, vomiting, diarrhea, or unexplained bleeding, within 21 days of travel to affected areas.
As we discussed in 2014's The New Normal: The Age Of Emerging Disease Threats, the reality of life in this third decade of the 21st century is that disease threats that once were local, can now spread globally in a matter of hours or days.
Between asymptomatic (or presymptomatic) carriage, and long incubation periods, vast oceans and prolonged travel times no longer protect us against infected travelers crossing borders.
Globally, airlines handle over 5 billion passengers and over 40 million flights per year; that's roughly 12 million passengers and 100,000 flights each day. In the U.S. there are roughly 160 airports which handle international flights.
With incubation periods that can range from a couple of days to several weeks, anyone who is recently exposed could easily change planes and continents several times before ever they ever show signs of illness.
Previous failed attempts to prevent the spread of H1N1 pandemic flu and COVID illustrate just how difficult interdiction really is.
- In 2010's Japan: Quarantine At Ports Ineffective Against Pandemic Flu, we looked at a study which found for every person identified, and quarantined, by port authorities - researchers estimated 14 others infected by the virus entered undetected.
- In April of 2012, in EID Journal: Airport Screening For Pandemic Flu In New Zealand, we looked at a study that found that the screening methods used at New Zealand’s airport were inadequate to slow the entry of the 2009 pandemic flu into their country, detecting less than 6% of those infected.
- And in late 2020, a CDC MMWR Risk Assessment and Management of COVID-19 Among Travelers Arriving at Designated U.S. Airports, January 17–September 13, 2020, found that `Symptom-based screening programs are ineffective because of the nonspecific clinical presentation of COVID-19 and asymptomatic cases.'
Surveillance can often identify acutely ill individuals when they are likely to be the most contagious so they can be promptly isolated, and it can provide important surveillance information. And it might even help slow the rate of entry of an emerging disease into a region, allowing additional time to mount public health interventions.
But as far as preventing an infectious disease like Ebola, MERS-CoV, or novel Flu from entering this - or any other country - airport screening is unlikely to provide much in the way of long-term protection.
The best place to try to stop the next pandemic is not at the inbound passenger gate, but in the places around the world where they are most likely to emerge.
But in our increasingly chaotic and insular world, that goal seems less obtainable with every passing day.
