How to Prevent Vaccine Loss

Preventing vaccine loss is not something that is fixed in one sitting. The frequency of vaccine threatening events is much higher than predicted and represents a real threat to vaccine inventory in a clinic or pharmacy.  But within each class of event, there are sub classifications; each of which requires a different risk mitigation strategy.

1. Power Outages:

Areawide power outages. Most power outages experienced by our clients were geographic versus building specific. The affected areas were most often a subset of the city or town. Most of these disruptions were related to one of three causes:

  • Severe weather – thunderstorms, windstorms, lightning, flood. Most of these occurred between April and November and were consistent with seasonal weather variations.
  • Construction in the area – road construction, new building construction. With every bit of road construction, there is always an opportunity for a backhoe to find an undocumented power cable or relay.
  • Power grid failures – network maintenance, overload, and substation failure. Power grids are always attempting to adjust to changing conditions as well as consumption and network disruption.

Building-related power outages usually occurred with after-hours maintenance. The most typical example involved third parties tripping a circuit breaker or fuse.


Power outages are almost impossible to prevent as the cause is beyond the clinic or pharmacy’s scope of influence.  The most important thing a clinic or pharmacy can do to prepare for a power outage is adequate planning.  This means that the staff needs to understand what type of power outage has occurred, who should be contacted, how the clinic identifies themselves to the power company and when and how the vaccine emergency plan needs to be implemented.

2. Thermostat manipulation errors

The most common reasons for thermostat manipulation errors are:

  • Changing the thermostat accidentally while loading inventory. Staff would Inadvertently push thermostat temperature buttons and turn dials as they were making inventory changes.
  • Inadequate temperature mitigation preparations. Insufficient water for temperature mediation and overstocked refrigerators were the most frequent culprits.
  • Thermostat overcorrection occurred when staff changed the thermostat without having a sense of the real scale of the individual thermostat triggering a pattern of correction and counter correction that only exacerbated the problem.

Three scenarios were prevalent:

  1. A large volume of the vaccine placed in the refrigerator or freezer compartment which triggered alerts and created an opportunity for errors related to the correction-counter correction cycle described above. Overcrowded refrigerators can also lead to a lack of circulation around the probes.
  2. A clinic or pharmacy placed too much room temperature water into the refrigerator too soon creating artificially warm temperatures.
  3. Staff perceived that the refrigerator temperature was too warm (but still within the proper range). In the example below the lead nurse in the lab thought the temperatures were getting too hot because they had a second, non-calibrated thermometer in the refrigerator. The nurse then made thermostat adjustments with the result being that the temperatures quickly dropped as low as 32.3°F.  A correction-color correction cycle then ensued.

preventing vaccine loss chart


  • Use only one thermometer in each compartment unless you have a large While multiple thermometers from different vendors in a single compartment provide the illusion of redundancy, they rarely read the same temperature leading to confusion among staff and can result in rapid, unplanned temperature changes by the team in the clinic or pharmacy.
  • Establish protocols for thermostat change. Changing the thermostat should be location protocol dependent and must include management approval of any change.
  • Ensure the use of proper temperature mitigation techniques. Water needs to be placed in the correct locations within the refrigerator to mitigate swings in temperatures.
  • Follow the Vaccine recovery plan. Clinics and pharmacies need to have a written process in place to correct temperature variation. Planning should not only provide the basics of location, contact information, and temperature limits but should also include the required response by Event.  An example would be an area-wide power outage.  Anyone reading the plan should know the emergency number of the power company, how they identify themselves, what questions to ask and, based upon the answers, the next steps to take.

3. Refrigerator or freezer door left ajar:

Loading new vaccines and managing inventory. Boxes, ties, and cables create “breaks” in the seals around the refrigeration compartment doors.  If there are multiple thermometers in the refrigerator or freezer, those cables can bunch up and create a “tunnel” in the door seal

Inattention at the end of the day leads to doors ajar due to slamming doors or shutting doors too gently. Because the staff leaves at the end of the day, there is no opportunity to catch these errors.  We nicknamed this the “5 o’clock syndrome”.


  • Establish inventory procedures that include verifying the door seal and noting the thermostat position before and after the inventory change and reorganization.
  • Two staff members per site should be responsible for verifying there are no doors ajar. In some situations, clinic staff assumed that somebody else had checked the refrigerator doors.

4. Other types of errors:

  • Failure to properly defrost the freezer in the dual compartment- single compressor units will change the dynamic of the compressor which in turn tends to over cool the refrigeration compartment.
  • Placing too much ice in the freezer changed the thermostat- compressor dynamic which would lead to overcooling in the refrigerator.
  • Vaccine stored in the refrigerator doors. Storing inventory in the doors instead of the refrigerator or shelves invites wide swings in temperatures as inventory changes.
  • Too much inventory in a refrigeration compartment disrupts airflow around the vaccines and the temperature probes. Depending upon the refrigerator this can push the temperatures readings out of range.
  • Ignoring alarms is most often a problem during the daytime if cold temperature alarms are triggered.


The problems above are all solved by following best vaccine storage practices as defined by the CDC.