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
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.)
Findings by the CDPH are significant, and warrant further action.
The following three scenarios illustrate this medication safety
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
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
In each instance, corrective action, including appropriate
follow-up with the patients and/or their families was required.
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
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
Dr. DeMartini is Deputy Director of the Office of Quality
Performance and Accreditation. In her role she provides
leadership and coordinates department wide initiatives that seek
to continually improve the quality and performance of programs
and processes within the Department of Public Health and
ultimately enhance the services provided to Californians. These
initiatives include quality improvement, strategic planning,
leadership development and succession planning. She is also
responsible for coordinating efforts to achieve and maintain
National Public Health Accreditation status.