In part 1 and part 2 of our series on distribution methods for pharmaceuticals, we looked at the current model of the pharmaceutical supply chain, which has evolved so significantly since the turn of the century that the federal government has passed stricter regulations, while the World Health Organization has recommended Good Distribution Practices (GDP) to ensure the safety and security of prescription medications.
In this post, we drill down to focus on vaccines. They act as a good example of how specialty medications increasingly require their own set of safety sub-guidelines – in this case, special care regarding temperature monitoring and control.
Proper vaccine storage and handling are important factors for inhibiting – and whenever possible – eradicating diseases that seriously threaten the health of global populations. Vaccines must be stored properly from the time they are manufactured until they are administered to the public. Otherwise, every time that a vaccine is exposed to an improper condition – especially a temperature excursion – potency is compromised and cannot be restored. Each year, preventable storage and handling errors result in costly revaccinations that are often too late, in addition to significant financial loss due to waste.
The vaccine cold chain begins with the cold storage unit at the manufacturing plant, extends to transportation of the vaccine and correct storage at the provider facility, and ends with administration of the vaccine to the patient.
The Cold Chain Flowchart. Source: CDC Vaccine Storage and Handling Toolkit
Throughout the cold chain, refrigerated and frozen vaccines must maintain their optimal holding temperature. Exposure to inappropriate conditions can affect potency of any refrigerated vaccine, as a single exposure to freezing temperatures can destroy potency.
Transporting vaccines increases the potential of a temperature excursion for many reasons, including uninsulated packaging, improper coolant materials, and warm spaces within vehicles created by engine heat or solar radiation. Ambient or spot temperature monitoring will not suffice; instead, only continuous, digital monitoring occurring within shipping containers can best ensure potency.
Proper containers are essential for the safe shipment of vaccines. These should include at minimum:
Each transport unit should be equipped with its own temperature monitoring device (TMD), placed in areas of the unit most likely to show fluctuations. If vaccines must be transported a long distance, a refrigerated truck is recommended.
To ensure that vaccines arrive safely, distribution crews should be trained to follow these good distribution practices:
Storage units must maintain proper temperatures at all times to ensure potency:
Continuous temperature monitoring is the only accurate method to reflect actual vaccine temperatures. A compliant TMD should be able to record:
Temperature monitoring data for each shipment should be stored for at least three years so that it can be analyzed for long-term trends. Digital storage is the best method of preserving data from loss, as well as for easy transmission to a regulatory agency.
The Centers for Disease Control (CDC) recommends a specific type of TMD called a “digital data logger” (DDL). A DDL provides the most accurate storage unit temperature information, including details on how long a vaccine has been exposed to a temperature excursion. Unlike a standard thermometer, which only shows the coldest and warmest temperatures reached in a unit, a DDL with a buffered probe offers the following advantages:
CDC does not recommend the following TMDs:
As medications become costlier and more specialized, the CDC’s guidelines for vaccine distribution are shifting towards digital solutions. In the case of vaccines, we can see how investment in a DDL is ultimately less expensive than replacing impotent vaccines wasted because of temperature excursions.
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