It might delay omicron’s arrival, but maybe not even that.
The Biden administration’s travel ban on eight countries in southern Africa went into effect on Monday, but it probably won’t do much to stave off omicron, a new, fast-spreading Covid-19 variant that was discovered in the region last week.
Travelers from South Africa, Botswana, Zimbabwe, Namibia, Lesotho, Eswatini, Mozambique, and Malawi are now blocked from entering the US, and American citizens and permanent residents coming from those countries must present a negative coronavirus test before traveling. Dozens of other countries have implemented similar measures restricting travel from the region, in addition to quarantine and post-arrival testing requirements for their own returning citizens.
President Joe Biden told reporters Monday that he was operating with very little information when he issued the ban, which was intended to buy his administration time to evaluate how to prepare for the inevitable arrival of omicron in the US. Scientists are still investigating whether omicron is more transmissible or more deadly than current variants. But as part of efforts to halt omicron, the Centers for Disease Control and Prevention has strengthened its guidance to encourage all US adults to get a booster dose of a Covid-19 vaccine.
“[W]hile we know that travel restrictions can slow the spread — they cannot prevent it. We will have to face this new threat,” Biden tweeted on Monday.
If anything, the ban may delay omicron’s arrival for a week or two. But unless coupled with strict quarantine and testing requirements for all travelers, past coronavirus-related travel bans haven’t achieved more than delays. These measures have been largely absent from the US’s pandemic response so far, but are reportedly under consideration.
“[Bans] have generally proved quite ineffective with the more infectious variants like delta, and so will likely do little more than slow the spread of omicron — not prevent it,” said Dr. Chris Beyrer, an epidemiologist at the Johns Hopkins Bloomberg School of Public Health.
The ban, therefore, carries limited potential upside. It not only punishes South Africa and Botswana, which were quick to alert the international community to omicron, but also other countries in the region that have suffered from inequitable distribution of vaccines globally. And it may be that the ban is too narrow — and was implemented too late — to delay omicron’s spread in the US: The variant was spreading in Europe at least a few days before it was discovered in South Africa. European travelers were then allowed to come into the US — and, as of Tuesday, they still are.
Travel bans likely won’t keep omicron out
Researchers have found that, if implemented correctly and at the right time, travel bans can temporarily slow the spread of Covid-19. But they can’t halt it altogether.
A Centers for Disease Control and Prevention (CDC) study last year found that the travel bans implemented by the Trump administration in early 2020 did not come soon enough to prevent the coronavirus from arriving in the US.
Another spring 2020 study, in the journal Science, found that travel restrictions in China implemented right after the virus was identified in Wuhan only slowed its spread internally by about three to five days. The study also said that international travel restrictions did help stave off the virus’s spread globally until mid-February, but that early detection, hand-washing, self-isolation, and household quarantine were more effective mitigation measures.
We don’t yet know whether the latest ban on travel from southern Africa was implemented soon enough to delay omicron’s arrival in the US. But it might also be too narrow to actually be effective.
For travel bans to be a useful tool to slow the spread of Covid-19, a country has to basically go all-in: Shut down their borders, require testing before a flight, enforce mandatory quarantine upon arrival for all travelers (even their own citizens), and test again five to seven days later, said Dr. David Hamer, a professor of global health at Boston University School of Medicine.
“But if it’s not very effectively implemented, it’s probably a waste of time,” he added. And against highly transmissible coronavirus variants like delta and possibly omicron, it’s even less likely to be effective.
Right now, US travel restrictions are far from airtight. International travelers are only required to provide proof of a negative Covid-19 test conducted within three days of their flight if they are fully vaccinated, or within one day if they are not fully vaccinated. (The US is reportedly considering requiring all international travelers, regardless of vaccination status, to take the test within a day of traveling as a means of mitigating the spread of omicron.)
Also, omicron has already been detected in 12 additional countries that are not covered by the ban, so travelers from those countries could still spread it. We now know it was in Europe before South Africa detected and reported its existence. And US citizens and permanent residents are still allowed to travel from banned countries; though they must be tested upon their return to the US, it’s possible they may be in the incubation period when tested. If so, their infection wouldn’t show up on a coronavirus test.
The ban therefore leaves plenty of potential for omicron to spread to the US imminently, if it hasn’t already. It’s possible that scientists have yet to detect the variant due to the CDC’s limited, but rapidly expanding surveillance capabilities. That could mean that the ban was useless from the start. And that uncertain protection comes with a high cost for the affected countries.
The travel ban penalizes the countries it is targeting
South African officials have rebuked the international community’s rush to ban travel from their country and others in Africa, with the foreign ministry claiming that it was “akin to punishing South Africa for its advanced genomic sequencing and the ability to detect new variants quicker.”
There’s some concern that the US’s decision to impose a travel ban on South Africa could create a chilling effect on other countries that might identify new coronavirus variants. If the world continually alienates such countries, it “disincentivizes countries from alerting others to threats that will inevitably land on their shores,” Tedros Adhanom, director-general of the World Health Organization, said in an address before the World Health Assembly on Monday.
“South Africa and Botswana should be thanked for detecting, sequencing, and reporting this variant, not penalized,” he added.
However, it’s not clear how strong that chilling effect might be. After the ban on travel from southern Africa went into effect, the Netherlands still came forward to announce that omicron was circulating within its borders earlier than previously known. But countries have not yet banned Dutch travelers.
Dr. Ashish Jha, dean of the Brown School of Public Health, has also warned that any upsides of travel bans have to be weighed against the kind of message they send to the international community:
The signal to the next country is
If you identify a variant and share it with the global community
You will be punished with a travel ban
I am not pro or anti travel bans
They can be useful in instances
But we should know that its weak tool for fighting a global pandemic
— Ashish K. Jha, MD, MPH (@ashishkjha) November 26, 2021
The ban punishes countries that, through no fault of their own, have not had the resources to vaccinate widely. Some, like South Africa, may not have the infrastructure to distribute the vaccines quickly or in some cases, store them at the necessary ultracold temperatures, forcing them to turn down shipments of additional doses. And much like the US and several European countries, they have also struggled to overcome vaccine hesitancy.
Wealthy countries like the US have hoarded vaccines in an effort to vaccinate and provide boosters to large shares of their populations. According to the WHO, countries that represent the world’s 20 largest economies have received more than 80 percent of the global vaccine supply. By comparison, less than 1 percent of all vaccines have gone to low-income countries, many of which are in Africa.
Wealthy countries may argue that they have the right to protect their own, but importantly, that also requires that the rest of the world gets vaccinated. If those inequities aren’t rectified, new variants may continue to crop up in countries where Covid-19 has been allowed to spread without widespread vaccination, possibly undermining the effectiveness of vaccines for all.
“We’ve been saying for a year that vaccine equity is not simply a matter of justice or ethics, but also of science,” Beyrer said. “You can’t leave billions of people unprotected and expect variants to not emerge.”