When Spirit Airlines learned that a Texas woman had died of covid-19 on one of its flights in July, the airline said it alerted the Centers for Disease Control and Prevention and received an acknowledgment from the agency.

But Spirit spokesman Erik Hofmeyer said it was never asked by health authorities to share passenger manifests to aid in tracking down people who might have been exposed.

State health officials in New Mexico, where the woman was declared dead after the Dallas-bound flight was diverted to Albuquerque, acknowledged they failed to investigate, as did the CDC.

The first the woman’s fellow passengers probably heard that her death was caused by the virus was in October, when The Washington Post and other news organizations were able to determine what flight the woman had been on, building on limited details about the case that were released by officials in Dallas County. By that time, it was far too late for the information to be useful in helping slow the potential spread of the virus.

Meanwhile, the CDC said it has no record of being contacted by Spirit.

Spirit did not respond to questions about how many passengers were on the flight.

The woman’s death was an extreme example of an in-flight coronavirus case, but it highlights the gaps in the nation’s efforts to protect citizens and improve the safety of air travel during the pandemic. The CDC and outside researchers both say limits on contact tracing and subsequent testing have made it hard to determine how air travel may be spreading the virus.

Responding to the virus

The federal government has largely been unwilling to set new rules for air travel, relying instead on recommendations and leadership from the industry. Only a few airlines offer preflight testing for the virus — mostly on select routes. The Department of Transportation recently rejected a petition from transportation unions to require masks on planes and public transportation.

Lisa Lee, an expert in infectious-disease epidemiology and ethics at Virginia Tech, said the government could be doing more.

“We’re still at the place where we have been since the beginning of this epidemic,” said Lee, a former CDC official. “Every airline and every airport has the responsibility to create their own covid-19 safety plan.”

“The primary tool we need is testing and very swift contact tracing,” Lee said.

The CDC typically coordinates with airlines and local officials to carry out contact tracing. But Caitlin Shockey, a CDC spokeswoman, said the agency has no record of a notification from Spirit or any indication that an investigation was launched.

Death investigators in New Mexico, where the woman was declared dead after the flight diverted to Albuquerque from Las Vegas, learned within two days that she had been positive for coronavirus and informed the local police and fire departments that responded to the scene, according to Dan Sosin, an epidemiologist at the state health department.

But Sosin said the health department itself received the test result directly from the lab, rather than from the Office of the Medical Investigator, and failed to conduct an investigation into the woman’s death. So it never learned that she had been on a plane and it didn’t initiate the tracing process with the CDC.

“The procedure we had should have picked it up,” Sosin said. “We’re reinforcing some of our written procedures about how this gets handled and revisiting with staff the importance of this follow up.”

The case illustrates how responsibility is shared between local, state and federal officials. Several federal agencies have a role in responding to the virus in the air travel system — including the Federal Aviation Administration, the CDC, the Transportation Security Administration and Customs and Border Protection — a factor that has complicated the government’s response.

In a statement, the Department of Transportation said it expects passengers to follow public health guidelines and that it stands ready to help wherever it can, even while it stresses that it is not responsible for public health.

“We will continue to apply our aviation expertise to help lead efforts with other Federal agencies, with industry, and with our international partners to address public health risk in the air transportation system, both internationally and here in the United States,” the department said.

The woman who died, a 38-year-old who had asthma and was obese, according to her autopsy, was on her way home from Las Vegas to Dallas. She boarded Spirit Flight 208 at McCarran International Airport on the evening of July 24, a Friday.

Nevada began reopening its economy May 1, with Las Vegas casinos opening back up the first week of June. By late July, the daily number of new coronavirus cases had reached a peak, climbing well above 1,000 on several days. On July 24, authorities reported 966 cases.

It’s not clear whether the woman knew she was infected with the virus or where she was exposed. A relative who was traveling with her told police she had been suffering shortness of breath, but a section in the police report detailing medical history makes no mention of covid-19 or the coronavirus. The relative declined to comment after the death was made public and could not be reached this past week.

The woman was not subject to any health screening by airport officials in Las Vegas, a hands-off approach that is in line with the stance taken by airports around the country.

Chris Jones, a spokesman for McCarran, said the airport has taken other steps to combat the virus, including mandating masks and reassigning people from desk jobs to cleaning duties.

“Everyone in the industry is in favor of making people comfortable with the idea of traveling,” Jones said. “The question is what is the best solution and how do you achieve it, and I think those answers are still to be determined.”

The airline industry unsuccessfully pushed the TSA to take on the job of screening passengers’ temperatures. The agency has been reluctant to do so, because, it said, it’s not clear the scans would be an effective strategy for identifying those infected with the virus. Frontier Airlines decided to administer temperature checks itself, but other airlines have not followed suit.

Short of formal screening, airlines have taken the approach of having passengers sign a declaration saying they have no symptoms and that they will abide by mask policies on board. But it’s not clear whether Spirit requires such a declaration. When asked if Spirit has such a policy, Hofmeyer directed a reporter to the airline’s covid-19 preparedness website. The website makes no mention of such a declaration.

Hofmeyer said Spirit crews are trained to try to spot sick passengers.

“Our teams are trained to look for various symptoms that might indicate a Guest is unfit to fly, and we also have a contracted medical provider for ground and in-flight expert medical assistance,” he said in an email.

'A patchwork of policies'

Flight 208 took off at 7:22 p.m. The woman soon started having difficulty breathing, according to the police report and her autopsy.

Her asthma inhaler didn’t help and she was given oxygen, but she soon fell unconscious. One of the flight attendants began administering CPR, to the extent that she passed out from the exertion. Remarkably, she later tested negative for the coronavirus, according to Spirit.

The plane diverted to Albuquerque, landing just over an hour after it had taken off. Emergency crews took the woman from the plane on a gurney and tried to revive her on the boarding bridge but abandoned their efforts after several minutes. The flight attendant who passed out was also given medical treatment.

A representative of the Office of the Medical Investigator, which reviews unusual deaths in New Mexico, soon arrived to declare the woman dead and take away her body. Within 24 hours, she had been swabbed to gather a sample for coronavirus testing, according to Alex Sanchez, a spokeswoman for the office.

It’s not clear how Spirit learned about the case. Hofmeyer said flight attendants who had been on the plane were notified and quarantined. But Taylor Garland, a spokeswoman for the Association of Flight Attendants, which represents the workers, said one of the four attendants on board was never notified. Hofmeyer did not respond to a question about the discrepancy.

“The lack of a federal covid-19 plan for aviation has been a problem throughout the pandemic,” Garland said. “As a result of this inaction, there is a patchwork of policies and procedures that inevitably leaves gaps.”

The autopsy report was not completed until Sept. 22, confirming that the woman had died of covid-19, exacerbated by her asthma and obesity.

The first the public learned of her death was when authorities in Dallas County added it to their tally of coronavirus deaths on Oct. 18. But officials there declined to say which airline she had traveled on and garbled key details, including listing the wrong hometown for the woman and saying she had died in Arizona. Officials offered no explanation for the delay between the time the autopsy report was completed and officials in Dallas County made it public.

Other countries and foreign airlines have been much more aggressive in their approach to tackling the virus, with many requiring visitors to show proof of a negative test before entering and offering tests at airports. In the United States, testing by airlines and airports is just beginning. United Airlines expanded its trial program this past week, as did Tampa International Airport.

Some foreign nations also are much more transparent in sharing information with the public. In Canada, for example, the country’s national health agency publicly discloses two weeks’ worth of flights on which there have been confirmed covid-19 cases. On a recent afternoon, the agency’s website listed 38 international flights and 45 domestic ones. The site doesn’t include a number of cases but identifies which rows are believed to be at risk.

“It would be great if we could look at a site like that,” said Lee, the former CDC official.

Research also increasingly points to cases of the virus being transmitted on flights. A new study by Irish researchers linked 59 covid-19 cases to one seven-hour flight to Ireland, demonstrating how widely sick passengers can spread the disease. The study, published in Europe’s journal on infectious-disease surveillance, epidemiology, prevention and control, found 13 passengers caused another 46 infections, in six of Ireland’s eight public health districts. The paper’s authors stressed the importance of rigorous contact tracing to contain outbreaks.

“This requires swift acquisition of the flight manifest, functioning contact details and enhanced surveillance of movements including transiting information,” the authors wrote.

Since the beginning of the pandemic, the CDC has tried to track at least 11,000 passengers on some 1,600 flights with cases. But Shockey said state and local officials are not required to share information about cases on planes, nor are they required to share any follow-up information on test results from people who were exposed.