When Vaccine Safety Fails, Who Is Responsible? New Blockchain System Traces the Chain of Accountability

Vaccines do not become safe and effective products simply by leaving a manufacturing facility. Their quality depends on an intricate chain of transportation, storage, handling and administration, where failures can compromise product integrity long before a dose reaches a patient. However, the information needed to investigate such failures often remains scattered across healthcare providers, manufacturers, logistics operators and regulatory authorities.

Researchers at the American University of Sharjah have developed a blockchain-based platform designed to connect these fragmented records. Their study, "A Blockchain Platform for Vaccine Beneficiary Registration, Side Effects, Cold Supply Chain, and Personnel Training and Employment Management," was published in the journal Sensors. Authored by Alia Al Sadawi, Malick M. Ndiaye, Israa Al Khaffaf and Omar Abdulkarim, the research proposes a unified system linking vaccine recipients, reported side effects, storage violations and the qualifications of personnel handling vaccines.

The platform goes beyond conventional shipment monitoring by introducing a mechanism for tracing reported medical events backward through a vaccine's distribution history. It also establishes automated controls to prevent personnel from undertaking responsibilities for which they lack appropriate certification. Successful prototype testing demonstrates the feasibility of integrating these functions, although the researchers acknowledge that operational and clinical validation remains necessary.

Vaccine safety has a data problem that begins before inoculation

Vaccine distribution involves a sequence of interconnected organizations, each responsible for preserving product quality. Manufacturers oversee production, logistics operators manage temperature-controlled transportation, storage facilities maintain required environmental conditions, and healthcare providers administer doses. Government authorities coordinate and regulate activities across the network, making reliable information exchange essential to effective oversight.

Cold chain integrity is particularly important because temperature excursions can reduce vaccine potency and undermine protection. The research illustrates these sensitivities through different COVID-19 vaccines, including products requiring ultra-cold storage and others maintained between 2°C and 8°C. Inappropriate exposure can cause wastage, increase replacement costs and weaken confidence in vaccination programmes.

Existing digital systems frequently address individual elements of this challenge without establishing connections between them. Healthcare authorities may possess beneficiary records and adverse-effect reports, while manufacturers and logistics companies maintain separate information about vaccine lots, environmental conditions and delivery movements. Training organizations and employers may independently manage personnel qualifications, adding another layer of fragmented evidence.

The difficulty becomes particularly apparent when an adverse event requires investigation. Establishing which vaccine lot a patient received is only one step; investigators may also need to reconstruct its transportation route, identify recorded temperature violations and determine which personnel were responsible for the affected supply chain stages. The researchers designed their platform to make this interconnected history available through verifiable digital records.

From cold chain violations to patient records: Building an unbroken evidence trail

The proposed architecture combines four interconnected smart contracts operating on Ethereum blockchain technology. These digital mechanisms manage vaccine supply chain movements, beneficiary registration and adverse-effect reporting, personnel training certification, and employment assignments. Together, they establish relationships between operational events that would otherwise require reconciliation across multiple databases and institutions.

Temperature and light sensors provide the environmental monitoring component. The system associates each vaccine lot with dedicated sensors and checks submitted readings against predetermined safety thresholds. When a violation occurs, the platform records the affected lot, environmental condition, location and time, creating a traceable history of handling incidents across the distribution network.

In a simulated test involving AstraZeneca vaccines, researchers configured acceptable temperatures between 2°C and 8°C. When a sensor submitted a reading of 10°C, the smart contract successfully registered a temperature violation. Additional testing demonstrated the recording of light exposure incidents and the rejection of shipment updates that violated the prescribed sequence of supply chain movements.

Patient information forms the second dimension of the architecture. Healthcare administrators register beneficiaries and record individual vaccination events, including dose numbers and vaccine lot identifiers. When a suspected side effect is documented, the system automatically associates that report with the relevant administered lot, allowing investigators to examine its recorded storage and transportation history.

The platform also accommodates multiple vaccination doses under a single beneficiary profile and permits authorized corrections to adverse-effect records. Rather than deleting previous information, amendments are preserved as additional entries linked to the original records. This approach maintains a transparent correction history while addressing the need to rectify inaccurate medical information.

Such integration creates opportunities for investigating relationships between patient characteristics, reported symptoms and recorded handling conditions. The researchers identify potential applications involving older adults, people with chronic illnesses and individuals with special needs. However, the system provides an infrastructure for investigating possible associations; it does not determine whether a particular vaccine, temperature deviation or production issue caused an adverse event.

A digital compliance gate puts workforce qualifications under scrutiny

One of the most distinctive contributions concerns an often overlooked dimension of vaccine safety: the qualifications of people responsible for handling temperature-sensitive products. Maintaining suitable storage infrastructure and monitoring equipment cannot independently guarantee correct handling when personnel lack the knowledge required for specialized transportation, storage and distribution responsibilities.

The researchers developed a certification mechanism based on nine training modules drawn from World Health Organization materials concerning the Pfizer-BioNTech COVID-19 vaccine. Personnel receive verifiable digital certificates after completing relevant modules, while employment smart contracts determine whether those qualifications correspond to particular responsibilities within the vaccine distribution network.

Unlike conventional credential repositories, the system connects certification directly with employment eligibility. An attempt to assign an uncertified employee, or a certified employee to an inappropriate supply chain position, triggers automatic rejection. The mechanism therefore makes qualification verification a prerequisite for certain operational assignments rather than merely a record available for subsequent inspection.

Workforce information also becomes part of the investigation process. When a cold chain violation occurs, authorities can identify personnel assigned to the relevant stage and examine their certification and employment histories. The blockchain preserves these records against retrospective alteration, creating a verifiable foundation for examining how responsibilities were distributed during an incident.

Nevertheless, the researchers distinguish traceable responsibility from established wrongdoing. Identifying an employee assigned to a stage where a violation occurred does not prove negligence or misconduct. Accountability assessments still require human investigation, particularly where equipment failures, organizational procedures or other circumstances may have contributed to an incident.

The approach illustrates how digital verification can connect workforce governance with pharmaceutical supply chain oversight. Its practical effectiveness would depend on reliable certification procedures, appropriately defined responsibilities and accurate personnel information, alongside the technical enforcement demonstrated by the prototype.

Tested at scale, but the decisive challenge is real-world deployment

The researchers evaluated their platform through functional simulations, transaction-cost analysis, security assessment and scalability experiments. Four smart contracts were deployed on Ethereum's Sepolia public testnet, where selected operations demonstrated confirmation times of approximately 11 to 13 seconds. Testing covered beneficiary registration, vaccination recording, adverse-effect documentation, temperature monitoring, personnel certification and workforce assignment.

Controlled scalability experiments examined increasing transaction volumes, including workloads reaching 100,000 operations. The researchers reported relatively stable gas consumption per transaction and predictable storage growth. For 100,000 beneficiaries receiving two doses each, estimated blockchain storage requirements reached approximately 25 MB for beneficiary profiles and 18.8 MB for vaccination-event records.

These findings support the technical feasibility of the architecture under tested conditions, but important operational constraints remain. Public blockchain transaction costs fluctuate, while frequent sensor submissions create demands on network capacity. The researchers identify permissioned blockchain networks and Layer-2 architectures as possible approaches for managing costs, improving performance and supporting deployment at national vaccination-programme scale.

Information integrity presents another challenge. Blockchain can preserve submitted records against unauthorized historical modification, but it cannot automatically guarantee that physical sensors provide accurate information. Device failures, interrupted connectivity and compromised data interfaces could produce incomplete monitoring histories. The authors consequently identify secure sensor communication, hardware authentication and tamper-evident mechanisms as priorities for further development.

Medical privacy also requires careful consideration because the platform connects identifiable beneficiary information with clinical records and vaccine histories. Although the prototype employs access restrictions, the researchers recommend examining permissioned blockchain architectures to strengthen privacy governance and regulatory compliance. Actual deployment would require safeguards suited to the healthcare environment in which the platform operates.

The absence of real-world validation remains the principal limitation. Testing used simulated scenarios rather than operational vaccination campaigns or actual clinical datasets. Consequently, the research cannot establish whether implementation would reduce vaccine wastage, improve clinical outcomes, accelerate investigations or deliver cost savings across functioning healthcare systems.

For governments, development agencies and pharmaceutical supply chain stakeholders, the architecture presents a potential model for more coordinated information management. Its relevance could extend beyond COVID-19 vaccines to other temperature-sensitive pharmaceutical products, although the researchers emphasize the need for appropriate validation before applying the approach in different contexts.

Upcoming work will involve healthcare authorities, logistics operators and administrators in assessing operational feasibility, alongside investigations into alternative blockchain networks and stronger sensor security. These evaluations will be essential for determining whether the demonstrated technical capabilities can withstand the complexities of everyday vaccine distribution.