MEXICO CITY - For months, health officials and hospital executives in Southern California watched as coronavirus vaccines neared their expiration dates unused while demand for doses waned.
A small group around San Diego had an idea: It would donate thousands of shots to Mexico, a short drive away, where the vaccine rollout had been much slower and the infection rate remained high.
But as the plan was readied, it was blocked by the White House Vaccine Task Force. The doses were instead discarded.
State and local officials across the country have run into the same problem, as the Biden administration has prevented efforts to donate leftover vaccines to India and other countries suffering from acute outbreaks.
The reason, White House officials say, is that vaccines in the United States are the property of the federal government, not the cities or states in which they are distributed. That means the federal government is liable for their use, and donation efforts must be run out of Washington. The White House runs its own program to donate vaccines, usually through the State Department and the U.S. Agency for International Development.
Related video: Why waving vaccine patents isn't enough to end the pandemic
The United States has given away more than 200 million vaccine doses abroad, carrying out President Biden's pledge to be "the arsenal of vaccines for the rest of the world." But it has denied multiple requests by local or state governments to donate soon-to-expire doses.
The policy has been particularly frustrating for health workers along the southern border, who have seen up close the demand for vaccines in Mexico, and the ease with which unneeded doses could be driven to Mexican vaccination sites in border cities such as Tijuana and Mexicali.
"It seemed like a win-win and something consistent with the Biden administration's goals," said Adolph Edwards, CEO of El Centro Regional Medical Center in California. "On the Mexican side, they were begging us for help. It's infuriating that we had to say no, when it would have been so easy to make a difference."
The conflict began several months ago, when health professionals and officials in San Diego County helped to identify 10,000 expiring vaccine doses and worked with their Mexican counterparts in Baja California, who agreed to receive, transport and deliver them. A vaccination site was identified - a shopping mall near the border in Mexicali - before the message arrived from Washington.
"I contacted the White House Vaccine Task Force and was told it was not possible," said Eric McDonald, chief medical officer for San Diego County.
The White House says legal liability means vaccines can be exported only by the federal government. If California, for example, distributed damaged vaccines, administration officials say, the federal government would be responsible.
"Given chain-of-custody considerations, moving doses out from more than 80,000 providers would involve significant legal and logistical challenges," said a U.S. official, who spoke on the condition of anonymity because they were not authorized to discuss export restrictions publicly. "We have examined those, and continue to work with states, CDC, FDA and CAG as we explore all options, but that process is being led at the federal level and states have been advised they should not be sending any doses internationally, due to these complex factors."
During the spring and summer, the gap between the U.S. and Mexican vaccination programs was wide.
"The contrast was huge," said Carlos González Gutiérrez, the Mexican consul in San Diego. "My 23-year-old daughter was able to get fully vaccinated in California, while in Mexico family and friends over 65 were still not able to get their first dose."
The difference has narrowed, but Mexico still does not have enough doses to open its vaccination program to most minors.
"The responsibility of vaccinating people lies with the Mexican government and I think we've done a good job of it," González said. "But we won't reach our full potential unless we continue to receive support from our friends in California."
The United States has donated 10.9 million vaccine doses to Mexico, making it among the top recipients. Nearly 40 percent of Mexicans have been fully vaccinated. But health officials on the border say they are frustrated that a bureaucratic hurdle is impeding an easy way to further expand vaccine availability in Mexico.
"It's hard to believe that it's ever better to let doses expire and throw them away rather than put them to use," said Jess Mandel, chief of pulmonary and critical care medicine at the University of California at San Diego School of Medicine.
In May, the university helped spearhead a drive to vaccinate 26,000 Mexican workers from 40 maquilas, factories that produce goods for export to the United States. Vaccine export restrictions meant the drive had to be held between Mexican and U.S. customs checkpoints.
Public health officials say they understand liability concerns, but they shouldn't preclude state and local donation efforts, particularly if recipient countries are willing to sign waivers.
"Not only do we have a moral imperative to help our neighbors," Mandel said, "but the better we can ensure that covid is controlled a few miles away on the Mexican side of the border, the more it will protect the health of people here in San Diego."
The U.S.-Mexico border has been closed to nonessential travel since March 2020. But tens of thousands of people still cross the border each day, many of them U.S. citizens or permanent residents who choose to live in Mexico, or essential workers who enter the United States for their jobs.
That cross-border traffic, and the severity of Mexico's coronavirus outbreak, were among the reasons, for some time, Southern California had among the country's highest caseloads. Next month, the border will reopen to nonessential traffic, raising new concerns about viral spread. Officials in California and Mexico are exploring ways to bring Mexicans across the border to be vaccinated in San Diego.
Across the United States, state health officials have repeatedly asked the federal government about the possibility of sharing expiring U.S. vaccine doses with nations in need. Those conversations became more urgent this summer as coronavirus cases spiked in India, while some U.S. states sat on unused stockpiles. Johnson & Johnson vaccines, in particular, piled up after regulators probed the shots' safety and Americans opted for mRNA vaccines from Pfizer-BioNTech and Moderna instead.
"Everybody was looking at that thinking, boy, we've got all this perfectly good vaccine that's going to expire, and in India they can't even get any," said Marcus Plescia, chief medical officer at the Association of State and Territorial Health Officials.
Plescia said "that conversation sorted itself out" after the federal government clarified the reasons it's impractical to share expiring doses. Pfizer doses, for example, need to be kept in cold storage, and there's no standard to ensure that health providers can safely gather and transport expiring doses.
The frustration in California notwithstanding, Plescia said state health officials generally support the federal government's caution.
"At least right now, there's not any kind of system or mechanism to provide any quality assurance to this," he said.
As of Oct. 11, approximately 4.6 percent of more than 486 million coronavirus vaccine doses have been wasted, according to federal data.
"This rate remains low, which is evidence of the strong partnership among the federal government, jurisdictions, and vaccine providers to get as many people vaccinated as possible while reducing vaccine wastage across the system," said Kirsten Allen, a spokeswoman for the Department of Health and Human Services.
The federal government is exploring ways to reabsorb unused vaccines that it could then send internationally, but it has run into logistical problems. Because vaccines are dispersed so widely, officials said, going from site to site to gather them would consume significant resources.
The Centers for Disease Control and Prevention has stressed publicly that it retains control over the vaccines, including the possibility of export. On its website, the CDC writes, the doses remain "U.S. government property until administered to the vaccination recipient."