When One Digit Matters: The Hidden Technology Behind Vaccine Safety

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A single wrong click might not seem like a major medical error.

Imagine a 5 year-old child walking into a pharmacy vaccine clinic during the COVID-19 pandemic, nervous for the needle poke but eagerly awaiting a reward for their patience and bravery. The vaccine is administered correctly, but during documentation, a pediatric vaccine formulation is accidentally entered into a vaccine registry as its adult version. The child still receives the protection that the immunization provides, leaves the pharmacy with a sticker and the much-awaited lollipop, and everything appears normal. But unknown to the child and their family, a small discrepancy now exists permanently within their medical record.

I came to learn that errors like these often emerge not from negligence, but from the complexity of modern healthcare systems and workflows. During my time working as a pharmacy clerk under the supervision of pharmacist Dr. Sreevani Singaraju at Qwark Pharmacy, I realized that most patients never think about what happens after receiving a vaccine. To them, the process may last only a few minutes: check in with me, answer a few questions about their medical history and insurance coverage, receive the shot, and leave. Hidden behind that interaction, however, is an extensive technological process tracking vaccine manufacturers, lot numbers, expiration dates, dosages and vaccine schedules, and patients’ histories.

Modern pharmacies are increasingly operating at the intersection of medicine and technology, with numerous databases, barcode systems, electronic records, and safety protocols operating behind the scenes of a pharmacist with a needle and syringe. One such technology is the California Immunization Registry (CAIR), a statewide digital system designed to centralize vaccination information across healthcare settings in California.

Working at Qwark Pharmacy, I observed that vaccine administration involved much more than preparing and delivering an injection. Dr. Singaraju consistently emphasized precision throughout the vaccine workflow, encouraging me and other staff to focus on details such as vaccine lot numbers, age-specific formulations, and accurate documentation practices. Despite these details seeming administrative, their relevance to patient safety became clear to me over time. 

Digital vaccine registries like CAIR act as more than just an online vaccine card usable by patients to show proof of vaccination: they consolidate vaccination histories into a system accessible by all California healthcare providers, preventing records from being isolated in individual pharmacies or medical clinics. This technology operates on a substantial scale. As of 2025, CAIR contains over 610 million vaccine doses across all age groups, with over 12 million records for young people between ages 0-18. The system centralizes information across all 58 California counties and is used by healthcare providers, schools, and public health agencies throughout the state.

These records influence everyday clinical decisions made by healthcare workers. For example, when preparing a vaccine, Dr. Singaraju often needed to determine whether a patient already completed a vaccine series, received a booster at another location, or missed a recommended dose. Without centralized information, providers like her would have to rely on paper documentation or patient memory, both of which are less reliable sources. But the functionality of these systems extends beyond individual appointments. During disease outbreaks like COVID-19, immunization registries help public health agencies like the Center for Disease Control (CDC) and the World Health Organization (WHO) identify vulnerable patient populations and understand vaccine coverage patterns on national or global scales. Instead of contacting each patient who was potentially exposed to disease, providers can determine which patients may already have immunity through existing digital vaccination records.

However, the reliability of these large databases depends on the accuracy of the information entered into them. In making every vaccine entry during Qwark Pharmacy’s COVID-19 and Influenza vaccination clinics, I entered multiple data points: vaccine manufacturer, lot number, expiration date, dosage information, administration site, and timing. Although a small documentation mistake in any of these data points may appear harmless initially, I knew they can affect future healthcare decisions, driving my careful data entry practices and auditing process.

Healthcare research indicates that these issues of data entry discrepancies are not uncommon in vaccination settings. Studies examining vaccination management found that nearly 89% of healthcare providers reported at least one vaccination error or near-error during their practice, often contributing to duplicate or missing vaccinations.

The COVID-19 pandemic further highlighted these challenges, with pharmacies ramping up large-scale vaccination efforts almost overnight. Vaccination recommendations changed rapidly, eligibility criteria evolved within weeks, and multiple vaccine formulations existed simultaneously. I found that pediatric and adult vaccines appeared very similar in the appearance of their vial, yet they contained very different concentrations and required different preparation methods.

Under these circumstances, routine vaccination tasks demanded greater attention. According to pharmacist Simona Dorf, PharmD, familiarity can create opportunities for mistakes. Dorf notes that “it is so easy to skip steps and think you have done this 1000 times” so healthcare workers administering vaccines are susceptible to thinking, “what could go wrong?” In addition, high-volume environments and pandemic demands can create pressure to move quickly, especially when pharmacists simultaneously counsel patients, process prescriptions, prepare vaccines, and document their work. This is where technology increasingly serves as a second layer of protection. 

Modern pharmacies rely on barcode verification and electronic documentation systems to minimize opportunities for human error. Dorf recommends providers to “check the vaccine administration record form carefully before mixing or drawing up the vaccine and scan the barcodes to ensure the same vaccine that is billed is being prepared for administration.” These digital systems catch inconsistencies before they affect patient care.

It is worth noting that these technologies act as an additional checkpoint supporting clinical practices; they cannot replace pharmacists or careful practice. Dorf highlights that “the best advice is to approach each vaccination with care.” Although slowing down may feel inefficient during busy clinical environments, the extra 20 seconds spent confirming information prevents larger problems. As Dorf explains, “the short amount of time to confirm the information is insignificant in comparison [with] the potential for error.”

As medicine continues evolving, vaccine technology will likely become more sophisticated, with artificial intelligence holding immense potential to identify discrepancies before vaccination documentation is submitted and becomes permanently embedded into medical records. In addition, greater integration of electronic systems may improve communication among hospitals, clinics, pharmacies, schools, and other settings where vaccine information is pertinent. Developments in automated verification systems also can reduce the reliance on manual entry of data points by pharmacy staff like myself.

Despite these advances, one lesson remains true: patients often remember the person who administered their vaccine, but they rarely see the technological frameworks supporting that interaction. Behind every appointment, there exists a network of healthcare providers, databases, and safety mechanisms collaborating to ensure that the right patient receives the right vaccine at the right time. Thus, technologies like CAIR are no longer simply tools for documentation; they have become an active part of healthcare itself.

In modern medicine, the most powerful technologies are often invisible, shaping patient care long before the needle ever reaches a patient’s arm. †

Written by Editor and Staff Writer Sriya Bairy (sbairy@ucsd.edu)

Works Cited

California Department of Public Health. “California Immunization Registry (CAIR) Updates.” California Department of Public Health, www.cdph.ca.gov/programs/cid/dcdc/cair/pages/cair-updates.aspx. 

Centers for Disease Control and Prevention. “California Immunization Information System (IIS): Policy and Legislation—California.” CDC, www.cdc.gov/iis/policy-legislation/california.html. 

Dorf, Simona. “Best Practices to Prevent Vaccination Errors.” Drug Topics, 4 Apr. 2022, www.drugtopics.com/view/best-practices-to-prevent-vaccination-errors. 

First Databank (FDB). “Best Practices to Prevent Vaccination Errors at the Pharmacy.” FDB Health, 4 Apr. 2022, www.fdbhealth.com/about-us/media-coverage/2022-04-04-best-practices-to- prevent-vaccination-errors. 

Immunize California. “CAIR Registry FAQs (Revised 02-2025).” ImmunizeCA, March 2025, www.immunizeca.org/wp-content/uploads/2025/03/Registry_FAQs-Revised_02-2025_CIC.pdf.

Immunize California. “CAIR Registry.” ImmunizeCA, www.immunizeca.org/ca-cair-registry.

Image Credit: Photo by Nataliya Vaitkevich, via Pexels (Pexels License). 

Image Credit: Smartphone Displaying Digital Vaccine Passport, by Leeloo The First, via Pexels (Pexels License).