More than nine months into the effort to vaccinate Americans against COVID-19, the patchwork nature of vaccination records is keeping Philadelphia hospitals from getting clarity on whether patients have had the shot.

“This is what everybody’s craving for,” said John Zurlo, division director of infectious disease at Thomas Jefferson University. “You’d hope we can get really accurate information about that and right now we really don’t get accurate information.”

Temple University Hospital and Einstein Medical Center also reported having trouble obtaining accurate records this year, though coordination with the Philadelphia and Pennsylvania departments of health have improved the situation, hospital personnel said.

Since vaccines were rolled out to the public earlier this year, doctors at Einstein have reported patients who are “100% sure” they were vaccinated not showing up in PhilaVax, the city database. Another record showed a patient to have gotten first doses in January and then again in April.

“Once you start seeing things like that you really can’t rely on it that much,” said Steven Sivak, president of Einstein Physicians Philadelphia.

» READ MORE: City and Philly Fighting COVID coordinated for months before scandal that was blamed on ‘acting in a hurry,’ emails show

Hospitals ask patients their vaccination status if it can’t be confirmed through records, and doctors described the records issue as more of an irritant than a major obstacle. But the lack of reliable vaccine records, Zurlo said, complicates efforts to precisely understand vaccine effectiveness and determine how many local hospitalizations and deaths are resulting from COVID-19 breakthrough infections. Nationally, that number is exceedingly low. The Centers for Disease Control and Prevention reported last week a study in Los Angeles that showed unvaccinated people are 29 times more likely to be hospitalized for COVID-19 than those who have received shots.

For city hospitals, unreliable records keep staff from confirming the vaccination status of patients who come to hospitals unconscious or otherwise unable to communicate, though all patients are tested for COVID-19. The lack of access to accurate records has no impact on a person’s treatment, though, doctors said. Hospital wards are not set up to segregate vaccinated from unvaccinated patients, both Sivak and Zurlo said.

The problem also inhibits efforts to encourage unvaccinated patients to get doses. At Jefferson, doctors talk with any patient identified as unvaccinated to encourage that person to get a shot.

“We’ve really been trying to push vaccinations among nonvaccinated individuals,” Zurlo said. “It should be and can be easily available if the information was sent to us and we had it in a chart.”

Incorrect data entry may play a role in some of the record inaccuracy, said James Garrow, a spokesperson for the Philadelphia Department of Public Health. But the biggest causes of confusion are twofold: complications accessing the city’s vaccination records and the lack of a national COVID-19 vaccination database.

“This has never been a problem in the past because there has never been such an immediate need for access to immunization records like we do for COVID vaccines,” Garrow said.

Exchanging information with PhilaVax requires health-care providers to meet a federally outlined data-sharing standard. Most health-care systems meet that standard, Garrow said, but at least one large city hospital system, Jefferson, does not — though it is in the process of updating its system, hospital personnel said.

Temple, Einstein, and Hospital of University of Pennsylvania meet those standards and have direct access to the city’s records, but even with that there have been complications.

Because Philadelphia handles vaccinations independently from the rest of the state, a city resident vaccinated in, say, Bucks or Montgomery County would not show up in the city’s vaccine records.

And there are a sizable number of those people. Garrow estimated close to 200,000 Philadelphians have been vaccinated outside the city.

When one of them seeks care at a hospital in the city, staff have to search both the city and the state’s immunization records to confirm the person’s vaccination status. Obtaining records for a patient vaccinated in New Jersey would require yet another digital connection.

Pennsylvania has had its own data entry issues. In July, the commonwealth acknowledged overcounting vaccinations by 500,000 people because it couldn’t properly track residents who got their two doses in two different places.

» READ MORE: Pa. vaccination doses were overcounted by 500,000 shots, state says

The lack of detailed information about Philadelphians vaccinated outside the city hinders the department of health’s efforts to accurately track demographic information, which is especially problematic in a city where lack of access and distrust of health institutions have left swaths of poorer neighborhoods, many of them predominantly communities of color, undervaccinated.

Temple and Einstein shared patient lists with the city to confirm their vaccination status, which allows the hospitals to import the city’s vaccination information directly into their internal medical records systems. The reconciliation is an arduous process that can take two weeks, though future searches will take less time, Garrow said.

That still doesn’t compensate for the overall lack of comprehensive record keeping nationally, he said.

The CDC issued a notice of intent at the end of June to hire seven contractors to modernize its vaccination record system and create a single gateway to access records for all Americans, but the city has received no notification of progress since, he said.

The CDC did not respond to requests for comment.

Fractured medical record keeping has been the subject of a decades-old policy debate. The 1996 Heath Information Portability and Accountability Act called for a national patient ID to create a central source for people’s medical records, but privacy concerns have kept a national registry from being created. Britain and Israel are among the countries that have such systems, said Tinglong Dai, professor of operations management and business analytics at the Johns Hopkins Carey Business School, which has made it easier to confirm vaccinations. The lack of a registry in the United States, he said, has become acutely problematic as people being asked for proof of vaccination have nothing but a card as documentation.

A national registry would also ensure consistent quality, he said, rather than the patchwork of record keeping used across the country now.

“This is definitely self-sabotaging,” Dai said. “I think there must be a significant portion of the population, including myself, who would really like to have that system so I wouldn’t have to carry around this card.”

For the city’s physicians, the complicated record system is one more hurdle in the effort to understand and treat patients amid another surge in COVID-19 cases.

“If it were to work perfectly it would be great,” Sivak said. “I was hoping I would finally have a source of truth for who got the vaccine and who didn’t.”