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What is an Immunization Information System, Why is it Important?

Forty-nine states have integrated an immunization information system into the EHR, which helps streamline patient immunization data during COVID-19 vaccination distribution.

Once integrated into the EHR, an immunization information system (IIS) helps improve COVID-19 vaccination distribution, administration, documentation, and monitorization by gathering and storing patient vaccination data, according to a study published in the Annals of Internal Medicine.  

Immunization information systems help ensure COVID-19 vaccinations across targeted populations as clinicians administer the vaccine across a tiered prioritization process.

There are currently 61 IISs across 49 states, Washington DC, three cities, and eight territories. There is currently only one state without an IIS and that state is in the process of launching the platform.

According to the National Vaccine Advisory Committee's standards, providers need to have full access to an individual’s immunization status at every medical encounter. EHR integration with the IIS could ensure that will happen.

“Despite these recommendations, many clinicians for adults are unaware of the existence of IISs and how to access them,” explained the study authors. “Additional training in this regard would be useful. Without accessing IIS data, clinicians have incomplete vaccination information to make decisions.”


IIS vendors customized the platform to fit local needs using the same Health Level 7 standards that EHR systems use to streamline patient data capture. It is key for clinicians to understand IIS product development to gain insight into its base functionality.

Although a web-based interface is available, the study authors recommended EHR integration for clinicians to easily query the IIS to gain patient data access.

The researchers said an efficient IIS EHR interface is reliable, fast, and easy to use. This integration mitigates barriers for busy clinicians and can reduce clinician burden. EHR integration boosts interoperability for providers and healthcare facilities to access immunization information.


Clinical vaccination sites are leveraging immunization information systems to order, distribute, and keep track of the vaccine.

With the IIS integrated into the EHR, clinicians can access COVID-19 vaccination status in real-time. Users can also gather and store patient data and document and track vaccine products and administered doses.

“With limited initial vaccine supply, IISs can assist in determining the equitable allocation of available vaccines, plan and forecast when additional doses are recommended, help ensure that patients are getting the correct vaccine, and monitor vaccination series completion,” explained the study authors.


Utilizing the study authors’ recommendations, clinicians can fully prepare themselves for COVID-19 vaccine administration and increase IIS use in four ways:

  • Becoming comfortable and familiar with the IIS EHR interface because patient vaccination information is readily available in the EHR workflow
  • Communicating with the health system’s health IT department to see if manual data requests are required or if there is a real-time data flow between the EHR and IIS platform
  • Getting onboarded by the state or local health department if the IIS system is not connected to the EHR system
  • Communicating and sharing knowledge about the IIS with colleagues, hospital leaders, and administration to spread IIS awareness

“Broad and equitable use of COVID-19 vaccines will be instrumental in mitigating and managing the pandemic,” wrote the study authors. “Immunization information systems are part of the critical infrastructure being used in COVID-19 vaccine plans to coordinate among multiple partners and systems for vaccine allocation, distribution, administration, and monitoring.”

To increase awareness and usability, clinicians need to increase their knowledge about IIS EHR integration and how they use it.

“The more clinicians are aware of and connected to their IIS, the better the vaccination campaign will be in addressing equitable vaccine distribution, managing vaccine uptake, and monitoring vaccination series completion,” concluded the authors. “Strengthening clinician engagement will lead to more robust IIS data, thereby enhancing clinical care and public health decision making, which are critical to immunization programs under routine and emergency conditions.”

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