Cloud Migration: Hurricane Response Vaccine Tracking

Following the destructive 2017 hurricane season, TechFlow revitalized and modernized the U.S. Virgin Islands Immunization Registry System (VIIRS) for a more resilient future. 

An AI-generated image showing the path of Hurricane Irma and Hurricane Maria in 2017.

Executive Summary

System Improvements

TechFlow’s improvements to the VIIRS helped reduce preventable disease outbreaks by identifying under-vaccinated areas, leading to a better understanding of disease spread.

Modernized Operations

Innovations in modernizing the VIIRS benefitted COVID-19 vaccination surveillance and program operations, giving public health care leaders and providers access to urgently needed data.

Significant Cost Savings

The VIIRS implementation helps to track and manage immunizations, which can lead to significant healthcare cost savings by reducing treatments related to preventable diseases.

2017’s one-two punch of category 5 hurricanes Irma and Maria devastated the U.S. Virgin Islands (USVI), leaving the USVI without any infrastructure to support its impacted population. 
After months of hard work restoring and rebuilding the bare minimum for sustenance, health issues began to resurface as a major concern.
In addition to damage across the islands, the hurricanes completely wiped out the VIIRS and its infrastructure. VIIRS plays a critical role in tracking the health of the territory’s population by maintaining immunization records, identifying high-risk groups across islands and ultimately enabling health care professionals to promote and administer immunizations more effectively.  The hurricanes literally blew away VIIRS software, servers, and application backups.   This presented two immediate challenges that put an already vulnerable USVI population at further risk:
  • Restoring the VIIRS infrastructure after it was rendered inoperable;
  • Reestablishing continuity of operations and maintenance of VIIRS, allowing public health officials and providers to resume the critical work of managing immunization coverage and disease prevention.

Adding complication to the challenges facing VIIRS in the hurricanes’ aftermath, USVI was unable to recover recent or salvageable backup tapes despite valiant efforts to quickly restore service. 


The VIIRS software source code, documentation, and data elements obtained in recovery were outdated and incomplete, with missing functions and support components. 


The TechFlow team had to essentially start from scratch to rebuild the system, with cooperation from the Centers for Disease Control and Prevention (CDC) and the Wisconsin Immunization Registry (WIR) Consortium.

The Solution

Rather than simply pursue recovery and restoration of the VIIRS server-based system, TechFlow designed a forward-leaning solution to move VIIRS into the future. By developing a cloud-based solution, TechFlow’s team could both modernize VIIRS and provide USVI a much-improved application. 


TechFlow’s engineers excitedly looked to optimize the application and its architecture by leveraging the cloud to not only get the Virgin Islands back up and running quickly, but also make the application and its data hurricane-proof for a resilient future.

An AI-generated image of a server room
An AI-generated image of a circuit board

TechFlow first had to piece together what it could about the previous software’s functionality. The TechFlow team engaged the Virgin Islands Department of Health (VIDOH), the CDC and other WIR Consortium system owners to obtain information and components that were part of the lost system. Confronting a lack of documentation and functional software, the TechFlow team embarked on an unplanned and highly technical series of reverse engineering exercises. 


Like putting together a puzzle with missing pieces, the team reverse-engineered existing code fragments, identified missing elements, determined software dependencies and modified or replaced code to create a secure and fully operational server-based IIS aligned to CDC’s Functional Standards. To facilitate cloud deployment, TechFlow created an alternative code library built for virtualization running on Amazon Web Services (AWS).

This time-consuming and intensive effort continues to pay off. The team’s ultimate success in modernizing VIIRS provided the CDC with a refactored, supportable, modern, and virtualized immunization software product that is cloud-ready, fast to deploy, and built for the future. 

As TechFlow completed its technical work, the team developed extensive training for Virgin Islands Department of Health staff members, medical providers and school nurses. TechFlow also shared materials and system documentation for use in additional future education and training, to ensure those using the system also derive significant benefit as they help the USVI on its continuing path to recovery.

An AI-generated image of a nurse preparing to administer a vaccine

In the United States, each state and territory has a similar critical need to protect the public by managing immunizations. In the USVI, TechFlow brought its “Always Ahead” approach to not only solve the challenge at hand, but also to create a solution that prevents and addresses problems in the future. 


Immunization Registry Systems play an important role in ensuring and maintaining a healthy population. In an era where the next disease outbreak could be around the corner, TechFlow’s forward-leaning solution creates a more stable, user-centric, extensible, cloud-based system that will help public health officials and providers better manage immunizations and improve public health.


TechFlow’s modernized VIIRS implementation was the first approved immunization registry to fully operate in the Cloud.

The Cloud-based solution restored data access across 17 organizations with 99.99% system availability despite challenging island conditions.

Hurricane winds and floods may someday return to the islands, but the critical data within the VIIRS is secure.

TechFlow's VIIRS stabilized the prior WIR system through Cloud deployment. Most of the USA and its territories can migrate to this more stable version, providing better health services for all.

The TechFlow team can further enhance VIIRS and others with data analytics across populations, shared insights from applied AI, and other impactful enhancements.

What They're Saying

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