As the coronavirus swept the globe, nervous countries imposed bans on flights, cruise ships and border crossings. But from the beginning, Mexico has stayed open. Radically open. New arrivals here aren’t required to show proof of vaccination or a negative coronavirus test, or to quarantine. When the omicron variant was detected, the United States slapped a temporary ban on visitors from eight African countries. Mexico didn’t stop a single flight.
The government estimates covid-19 has caused more than 450,000 deaths. Yet perhaps no other large country so acutely represents the difficult trade-offs involved in trying to slow the spread of the virus. Mexico has tens of millions of poor citizens and an economy dependent on trade and tourism. It shares the world’s busiest land border. With omicron now taking off, it’s one of many nations asking: How much can you seal yourself off?
“You have to make these impossible choices almost — is it your economy or public health?” said Kelley Lee, a global health scholar at Canada’s Simon Fraser University. Countries that imposed strict testing and quarantine requirements have clearly done better at limiting coronavirus outbreaks, she said. “The challenge is most governments aren’t willing to go that route. There are costs, real economic costs, political costs, social costs.”
Health professionals have wrestled for years with the question of how to slow the transmission of disease in an ever-more-globalizing world. In 2005, most countries adopted a new version of the International Health Regulations that discouraged closing borders at the outset of pandemics. Many scientists believed travel bans had little effect against nimble viruses. Worse, such measures could discourage nations from revealing outbreaks, for fear of being hit with economy-crippling travel bans. The rules obliged countries to monitor and quickly report public health threats, and sought to ensure they’d get help.
Hugo López-Gatell, who leads Mexico’s coronavirus response, knows firsthand the costs of travel bans. One Saturday afternoon in 2009, he got a query from the Pan American Health Organization about news reports of an unusual flu outbreak in the state of Veracruz. López-Gatell, then chief epidemiologist at the Mexican Health Ministry, gathered all the available data and sent back a report the next evening. It turned out to be the start of the H1N1 flu pandemic. Mexico was “absolutely, proudly, compulsively transparent,” he recalled.
Nonetheless, one nation after another canceled flights to and from Mexico or warned their citizens away from the country. The economy slumped.
A subsequent study by European scientists found that the restrictions contributed to a 40 percent drop in international air traffic to Mexico — but an average delay of only three days in the virus’s arrival in other countries.
Alessandro Vespignani, a physicist at Northeastern University, was a co-author of that study. “Before the [coronavirus] pandemic, the mainstream thinking was, okay, travel restrictions do not have an effect,” he said.
Then came SARS-CoV-2 — the novel coronavirus that causes covid-19 — a far more infectious pathogen than the typical flu. Scientists began to reevaluate their beliefs.
They were startled at how effectively some countries contained domestic transmission of the coronavirus. China has prevented a nationwide outbreak by imposing draconian measures, including banning many foreigners and locking down tens of millions of citizens. New Zealand and Australia adopted “zero-covid” strategies that left them with a tiny fraction of the number of deaths in other developed countries.
Still, analysts note, those countries had political and geographical characteristics that set them apart. China’s authoritarian system enabled it to implement “a very, very painful strategy, which I’m not sure a large Western democracy could follow,” said Lawrence Gostin, a professor of global health law at Georgetown University. Neither Australia nor New Zealand has land borders; both have relatively small populations and strong economies.
To succeed, experts say, travel bans generally have to be early, strict and comprehensive. That’s not a good description of the restrictions many countries imposed on visitors from southern Africa after omicron was identified there. The U.S. government, for example, allowed its citizens to return from the region without quarantining — potentially bringing the virus with them. Moreover, by the time the U.S. ban took effect on Nov. 29, omicron was present in Europe, Hong Kong and Israel.
For many countries, “closing your border is mostly a political symbol that you are tough on the pandemic,” Gostin said. (Biden administration officials say the month-long ban was aimed at buying time to prepare for omicron.)
Mexican officials didn’t just reject bans on flights from countries with outbreaks. They’ve never required visitors to show evidence of vaccination or negative coronavirus tests. López-Gatell said such measures would be ineffective. Travelers could present fake tests. Or they might carry infections that weren’t yet detectable when they were swabbed. “You let them in, and the next day one of them wakes up with a fever because his period of incubation ended,” he said. “And now he’s infecting his family of 40 in a village in Mexico.”
For a country such as Mexico, which depends on tourism for nearly 9 percent of its gross domestic product and has a massive flow of migrants, workers and students across its nearly 2,000-mile border with the United States, the cost of imposing travel restrictions “is too high compared to the usefulness,” López-Gatell said. And once a variant such as omicron starts multiplying, he said, locally transmitted cases dwarf the number arriving from abroad.
Former top Mexican health officials have condemned the policy, saying the government is prioritizing the economy over citizens’ lives.
“There’s no fatalistic situation that we just have to accept,” said Jaime Sepúlveda, the former director of Mexico’s National Institutes of Health who now heads the Institute for Global Health Sciences at University of California at San Francisco. He noted that other upper-middle-income countries have held down covid-19 deaths by imposing more aggressive policies, including instituting border controls. He characterized Mexico’s response as part of a broader failure to manage the pandemic.
A report produced by Sepúlveda and other health professionals for the World Health Organization last year criticized Mexico for its lack of testing, limited economic relief packages and insufficient promotion of mask-wearing. The public messages from President Andrés Manuel López Obrador’s government “prioritized keeping up appearances” rather than safeguarding health, the authors said.
Samuel Ponce de León, the epidemiologist who heads the National Autonomous University of Mexico’s coronavirus committee, said he doubted that border controls would have much effect on restraining the highly transmissible omicron. “We don’t have the logistical capacity, the infrastructure, to control all the points of entry well,” he said. And such controls “would have an important economic impact.”
But he criticized López Obrador for downplaying the new variant. As recently as last week, the president said it was unclear whether Mexico would have a new coronavirus wave. Since then, the number of new infections has shattered daily records. (Hospitalization rates remain relatively low).
“In these situations, you have to prepare for the worst-case scenario,” said Ponce de León.” There’s no place here for optimism. And politicians tend to be excessively optimistic.”
On Monday, López Obrador tested positive for the coronavirus — for the second time.