Check Your Medication Refrigerators

CDPH Alert

During Medication Error Reduction Plan (MERP) Surveys, CDPH pharmaceutical consultants continue to identify circumstances whereby refrigerated vaccines have not been properly stored in accordance with manufacturer’s specifications. These occurrences involve refrigerators located in various areas, including emergency departments, in-patient pharmacies and out-patient clinics.

California regulation requires refrigerated medication storage temperature to be maintained between 2.2° Celsius (36° Fahrenheit) and 7.7° Celsius (46° Fahrenheit) — California Code of Regulations, Title 22, Section 70263 (q) (6).

For most vaccine manufacturers, the recommended refrigerated storage temperature is from 2° to 8° Celsius. Diphtheria, tetanus, hepatitis and pneumococcal vaccines have aluminum adjuvants: adjuvants are used to modify or augment the effects of a vaccine by stimulating the immune system to respond to the vaccine more vigorously. When these vaccines are stored below freezing temperatures, the immunogen separates from the aluminum reducing the vaccine’s potency; repeated exposure to freezing temperature will render the vaccine ineffective. (For live vaccines, such as MMR, varicella, MMRV and yellow fever, potency loss is seen at higher temperatures.)

Survey findings

Findings by the CDPH are significant, and warrant further action. The following three scenarios illustrate this medication safety concern.

During one hospital MERP survey, 3,921 patients were identified who had received vaccines following storage at subzero (freezing) temperatures. Temperatures were determined to be out of range for over 32 months. Continued investigation revealed patients who had received improperly stored vaccine who later died from the disease the vaccine was otherwise intended to prevent.

Another MERP survey identified 6,471 patients who had also received vaccines after storage at subzero temperatures. Temperatures were determined to be out of range for approximately 16 months.

A third hospital had administered improperly stored hepatitis B vaccine to 1,636 newborn babies over a 6-month period (investigation revealed five mothers who were positive for hepatitis B).

In each instance, corrective action, including appropriate follow-up with the patients and/or their families was required.

System failures

All three hospitals had common system failures around monitoring their medication refrigerator temperatures. These failures included: inadequate understanding of the monitoring system; lack of accountability in ensuring temperatures were properly maintained; and, inappropriate, or no action taken when temperatures were found out of range.

Inadequate understanding of the monitoring systems is especially problematic around electronic monitoring thermometer systems. Many of these systems can be set with temperature out-of-range parameters which trigger built in alarms to alert users. In one case, the hospital had set an out-of-range alert parameter for four hours. As set, the alarm would only go off when the temperature had been out of range after four hours. In another case, while the alarm went off, the staff was unaware of its purpose and it was ignored. Another hospital used temperature wheels, also an electronic system, whereby temperatures are logged on a paper wheel; however, staff did not know how to correctly interpret the recorded data.

Lacking clear accountability in ensuring that refrigerator temperatures are properly maintained is also problematic. One hospital did not have an assigned primary person, or a designated backup person for monitoring temperatures; it was believed the maintenance department would take care of the refrigerators. When maintenance department staff members were interviewed, they indicated the pharmacy department was responsible.

Finally, there were hospitals which took inappropriate action for out of range medication refrigerator temperatures. One institution, after discovery of improper storage, returned the vaccines to inventory and dispensed the reduced potency vaccines. Another hospital had staff monitoring for, and documenting to, subzero temperatures. Nevertheless, they failed to act upon the temperature excursions.


CDPH recommends each facility review its process and procedures for ensuring refrigerated medication, including vaccines, are adequate to achieve storage within the appropriate temperature at all times. CDPH further recommends designation of primary and backup personnel for temperature monitoring, including scheduled visual inspection of storage areas, to include preventive maintenance and testing of refrigerators and monitoring devices.

If you have any questions, please contact Loriann De Martini, PharmD, Chief, Pharmaceutical Consultant at 916.552.8645 or