COVID-19 Resource Center

COVID-19 Resource Center


Healio Interviews

Disclosures: Adalja and Marrazzo report no relevant financial disclosures.
February 05, 2021
3 min read

Variants will continue to spread despite travel restrictions


Healio Interviews

Disclosures: Adalja and Marrazzo report no relevant financial disclosures.
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Last week, President Joseph R. Biden Jr. signed an order suspending entry into the United States of any noncitizens traveling within 14 days of being in South Africa.

Biden also reinstated restrictions on travelers to the U.S. from Brazil, the United Kingdom — excluding overseas territories — Ireland and an area of Europe encompassing 26 countries.

Amesh A. Adalja
Jeanne Marrazzo

In announcing the newly signed restrictions, the White House cited concerns about SARS-CoV-2 variants first recorded in Brazil, South Africa and the United Kingdom, which have raised fears about vaccine effectiveness.

Experts have debated the usefulness of travel restrictions to control the spread of pathogens, saying that history has shown them to be ineffective, and sometimes even counterproductive, although acknowledging they could sometimes be necessary.

Amesh A. Adalja, MD, a senior scholar at the Johns Hopkins Center for Health Security, said it is important to remember that “even with travel restrictions, the variants are spreading in the United States and we should not get a false sense of security by these measures.”

“I think that there needs to be a distinction drawn between travel bans and travel restrictions, Adalja told Healio. “For example, we have the testing technology to be able to facilitate travel in a relatively COVID-19-free manner, it just needs to be implemented — at the gate.”

Jeanne Marrazzo, MD, MPH, FACP, FIDSA, director of the division of infectious diseases and endowed chair in infectious diseases at the University of Alabama at Birmingham School of Medicine, said travel restrictions can and do work.

However, “timing is everything,” said Marrazzo, who is also an Infectious Diseases News Editorial Board Member. The efficacy of such restrictions depends on accurately identifying travelers who pose a real risk, she said.

“COVID-19 has posed a special challenge, because at least half — and possibly more — of all transmission comes from people who are infected but don’t know it — either they don’t have symptoms, or they don’t recognize them as concerning for COVID,” said Marrazzo. “For this reason, broadly applying travel bans to a region that is believed to be the source of a specific concern could be effective.”

The emerging variants are thought to be more transmissible, with the potential to bypass immunity elicited by natural infection or vaccination.

Researchers have predicted that the variant discovered in the U.K., B.1.1.7, could be the dominant SARS-CoV-2 virus in the U.S. by March. According to the CDC, the variant spreads more easily and quickly than other variants, and experts in the U.K. have reported that it may be associated with an increased risk for death, although more studies are needed to confirm this.

The B.1.351 variant that was first identified in South Africa is the most worrisome, National Institute of Allergy and Infectious Diseases Director Anthony S. Fauci, MD, and other experts have said. The variant first identified in Brazil is known as P.1. According to the CDC, all three have been detected in the U.S., although it is unclear how widespread they are.

Marrazzo said experts believe the window of opportunity to prevent variants from entering the U.S. or spreading out of control has closed. She said travel bans could prevent the importation of even more variants that could potentially emerge in response to various pressures, “but that is highly theoretical at this point, and the overall effect of such bans — including the human, societal and economic implications — needs to be carefully considered,” she said.

Regardless, Marrazzo said it is essential that the U.S. increases efforts to monitor emerging variants travel restrictions or not.

“The only reason we even knew about the B.1.1.7 strain is because the U.K. has one of the most aggressive and sophisticated sampling and sequencing approaches — if not the most — in the world. We have nothing like that in the U.S. at this point, like many countries,” Marrazzo said. “The only way we’ll be able to catch the emergence of these and new variants is to have a system in place to know what’s coming — and any travel bans, if appropriate, should be informed by those data.”


CDC. New COVID-19 variants. Accessed on February 4, 2021.

The White House. Proclamation on the suspension of entry as immigrants and non-immigrants of certain additional persons who pose a risk of transmitting coronavirus disease. Accessed on February 4, 2021.