When there's a coronavirus vaccine, how will we make sure everybody gets it? That's the job of state immunization registries.

A collection of 62 obscure state and local agencies may end up being crucial players in the fight against coronavirus once vaccines become available.

They’re known as immunization registries and they keep track of children’s – and increasingly adults’ – immunizations.

Vaccines against the SARS-CoV-2 virus that causes the disease COVID-19 are expected to require two doses, given a month or so apart, and come in several types. That’s a recipe for disaster without a central repository to know who got what vaccine and when.

Imagine this scenario: You get your first coronavirus shot at a local health department clinic. A month later, when it’s time for your follow-up, you go to your doctor or a local pharmacy.

“They’ll need to know which one you got, when you got it and double-check when you’re due for your second dose,” said Dr. Kelly Moore, associate director of immunization education with the Immunization Action Coalition.

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That's where existing state immunization registries should come in, public health experts say. Multiple doses and different vaccines aren't just a logistical nightmare, there are health implications as well.

“There could be unknown reactions and no one’s going to have time to do studies to see if you can mix and match,” said Rebecca Coyle, executive director of the American Immunization Registry Association in Washington, D.C.

Researchers work in a lab at the Yisheng Biopharma company in Shenyang, in Chinas northeast Liaoning province on June 10, 2020. - The company is one of a number in China trying to develop a vaccine for the COVID-19 coronavirus. (Photo by NOEL CELIS / AFP) (Photo by NOEL CELIS/AFP via Getty Images) ORIG FILE ID: AFP_1T723P
Researchers work in a lab at the Yisheng Biopharma company in Shenyang, in Chinas northeast Liaoning province on June 10, 2020. - The company is one of a number in China trying to develop a vaccine for the COVID-19 coronavirus. (Photo by NOEL CELIS / AFP) (Photo by NOEL CELIS/AFP via Getty Images) ORIG FILE ID: AFP_1T723P

Gearing up to vaccinate more than 300 million Americans – twice – in a short period of time, the Centers for Disease Control and Prevention is working closely with the registries and state health departments to streamline the somewhat clunky existing system.

Prior to the pandemic, the CDC was engaged in a long-term effort to build a centralized system to let health care providers and state registries quickly and easily share information about immunizations. Dubbed the IZ Gateway, it’s now receiving a lot of attention in public health circles.

Whether such a system will be available in time for the onslaught of coronavirus vaccines isn’t known. The CDC did not respond to multiple emails.

The IZ Gateway is anticipated to play a role with a SARS-CoV-2 vaccine, Coyle said, but “there are still some policy and technology issues that need to be resolved before it can truly be leveraged on a national scale."

Immunization registries started for children, now for adults, too

The registries are part of a robust federal system that orders, manages and distributes vaccines nationwide through the Vaccines for Children program, which pays for vaccines for about half of America’s children.

To track the effort, which began in 1994, each state created a registry to ensure every child gets the immunizations they are eligible for. It has since been expanded to include many adults as well.

There’s a lot to track. Last year the Minnesota Immunization Information Connection logged 5.87 million immunizations, more than half in adults. Only 24% of the state’s medical providers aren’t enrolled in the system, said Doug Schultz, an information officer with the Minnesota Department of Health.

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In Michigan, every person born since 1993 is in the system, unless they opted out. Today that’s 2.4 million children and 7.9 million adults, said Bob Swanson, director of the division of immunization for the state’s Department of Health and Human Services.

All states except New Hampshire have their own immunization registries. Some counties and cities also have their own, such as New York City and San Diego. Including U.S. territories such as America Samoa, there are 62 such registries.

Pharmacist Michael Witte holds a tray with a syringe containing a shot that will be used in the first-stage safety study clinical trial of the potential vaccine.
Pharmacist Michael Witte holds a tray with a syringe containing a shot that will be used in the first-stage safety study clinical trial of the potential vaccine.

Adding coronavirus vaccines shouldn’t be a heavy lift for most, said Coyle.

There are well over 200,000 health care provider sites already connected to the registries, so reporting vaccinations won't be out of the routine for them. But it will be new for many facilities such as nursing homes and other locations that haven’t reported immunizations to a registry before, she said.

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The biggest challenge will be exchanging data across state lines. The registries were set up at the state rather than the federal level due to privacy concerns. To share information with another registry, a data-sharing agreement must be signed.

With 62 registries, that’s more than 1,800 different agreements to sign and keep up to date. Many don't.

There’s no agreement, for example, between the District of Columbia, Virginia and Maryland, despite their close proximity. That means someone might get their first coronavirus shot at their workplace in the district, their second in Virginia where they live, or at their doctor's office in Maryland and the records would be unavailable.

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Usually, the best data sharing is between states near each other. Washington state and Oregon have long had data sharing, given that many people work in Portland, Oregon, but live across the Columbia River in Vancouver, Washington.

Unfortunately, not everyone moves between two contiguous states. Think snowbirds.

Each winter, tens of thousands of retirees leave northern states and head to second homes in the sunny South. Depending on when vaccines become available, they might get their first shots at home and their second ones in Florida or South Carolina.

If vaccines become available in the fall when they’re on the move, tracking “is going to be critical,” said Coyle.

Immunization registries have history of dealing with crisis, including hurricanes

The registry system has stepped up in times of crisis before.

After Hurricane Katrina hit Louisiana in 2005, thousands of families moved to Alabama, Mississippi, Texas and other states. To enroll their children in new schools they had to provide immunization records.

“You can’t ask a parent for their child’s vaccine record when they’ve just been flooded out,” said Claire Hannan, executive director of the Association of Immunization Managers.

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Louisiana issued an emergency order so any state that wanted to access the system could get it, streamlining the process.

“It worked really well,” Hannan said.

In 2009, when the H1N1 influenza pandemic hit, flu vaccine was distributed by the federal government through state health departments and tracked by the registries. It was still clunky, with some states requiring providers to fax in orders, but it worked remarkably well.

Over the last 11 years, the infrastructure has gotten much more robust. “It’s just a matter of making the connections and coordination,” said Hannan.

State health officials 'identifying gaps' ahead of availability of coronavirus vaccine

The scramble is on to get ready for the day coronavirus vaccines become available. Directors of the immunization programs and state health agencies have set up work groups and are having calls every two weeks with the CDC and immunization registry managers, said Hannan.

“States are looking at their immunization information systems, identifying gaps and looking at what they might need to do to improve them and ensure they're ready,” she said.

COVID-19 does add some new wrinkles. For example, the registries and CDC realized some kind of immunization confirmation will be necessary.

“Consumers need to be able to print something out to show their employers, it’s going to be an important piece,” Hannan said.

More money is one thing few registries seem to be getting as they prepare for the onslaught.

“Currently, we don’t have any new budget to cover this work,” said Michigan’s Swanson.

This article originally appeared on USA TODAY: Coronavirus vaccine: State immunization registries hold key to success