Are my vaccines at risk?

Most independent clinics and pharmacies would answer that question has “no”.  But the truth is more complicated and the risks more diverse than perceived at the individual clinic or pharmacy level. This is why vaccine temperature monitoring is so crucial.  To answer the question with real data from our our client base, we analyzed over 5 million temperature readings to gain better insight for us and our clients.


Multiple papers document storage mishandling risks in clinics. The report by the Office of the Inspector General (Vaccines for Children Program: Vulnerabilities in vaccine management. Published in June 2012: OEI-04-10-00430). showed a high percentage of “nonconforming clinics.” Other studies have documented outbreaks of vaccine-preventable illness due to noncompliance with the established standards. While these studies have been beneficial, they have not necessarily been very specific about the root causes of failure and suggested remediation strategies.

The Vax-Shield study

The Vax-Shield service is unique among “continuous vaccine temperature monitoring with alerts” service providers because we intimately involved with our clients to help mitigate risks to their vaccine storage and track the source of failure. We follow incidents from initial notification through problem resolution. This increased involvement allows for a much more detailed analysis of the data over a much longer time than previous studies.

The study “population “

The Vax-Shield client base consists of small to medium-sized independent clinics and community pharmacies. These sites tend to have limited staff and no IT resources on site. The refrigerators involved in this study were both dual compartment units running on a single compressor and single compartment units. This study does not differentiate between those two categories.

Vax-Shield collected and analyzed its client site data from a 2 ½ year period lasting from January 1, 2015, through July 1, 2017.  We focused on “Vaccine Threatening Events”(Events) as defined in the “methodology” section of the study, their outcomes, cause, and resolution.


We found that the incidence of Vaccine Threatening Events / Client location (Figure 1) was much higher (56%) than we anticipated with the primary cause being staff errors followed by power outages. The incidence of nonemergency refrigeration replacement was also quite high with over a 35%  of the refrigeration units preemptively replaced over the study period.  Our clients saved Millions of dollars in vaccine and other medications during the term of the study.

Figure 1

vaccine temperature monitoring chart

What is a “Vaccine Threatening Event (Event)”:

We chose to focus on the type of incidents would truly impact the viability of vaccine and other refrigerated medications were it not addressed promptly.  In addition, we did not count those Events that occurred during working hours.  Four classes of Events were chosen:


  • A power outage at a site of over two hours in duration with elevated temperatures which took place when staff was not in the clinic or pharmacy.
  • A significant change in temperature that posed an immediate risk of spoiling vaccines and which took place when staff was not in the clinic or pharmacy.
  • An adverse change in temperature that immediately threatened the vaccines. For example, a sudden drop in temperature in the refrigerator to near freezing. (Conversely, an increase in temperature from 8°C to 9°C would not qualify)
  • A mechanical failure which occurred when staff were not in the Clinic or Pharmacy Location

Also, Vax-Shield kept track of sites who opted to preemptively replace the refrigerator or freezer rather than risk a mechanical failure in the future. By comparing observed refrigeration temperature patterns and other factors to established norms, Vax-Shield was able to assist its clients in making this decision.


Vax-Shield grouped the root causes of the Events into the following categories:

Staff Error

  • “Thermostat” refers to rapid temperature changes due to client staff manipulating the thermostat in the refrigerator or freezer either purposely or accidentally to the point where it threatens the vaccine stored.
  • “Door Ajar” refers to client staff leaving a refrigerator or freezer in a state where the refrigeration seal around the door is not intact.
  • “Other” refers to errors such as improper use of ice packs, misreading temperature data, etc.

Power Outage: A power outage lasting over two hours that results in a temperature excursion.

Refrigeration Failure: A catastrophic refrigeration failure. In all but one case, the cause of the issue was the inability of the compressor/coils to cool the refrigeration compartments.  These situations result in the relocation of the vaccine and rapid refrigerator replacement.  We do note that best practices indicate that a new refrigerator should run for a week before trusting it with vaccine and medication lots.  In the real world, this is not always possible

OTHER Classifications

Preemptive Mechanical Replacement: We based this classification upon unusual temperature patterns relative to established norms. When we detect these trends, we notify the client and help them plan to replace the refrigeration equipment.


Results and Discussion

Of the sites that experienced an Event, staff mistakes triggered three-quarters of the Events (Figure 2). Power outages account for less than 19%.  This was far higher than we expected.

Figure 2

 vaccine temperature monitoring chart

Over 50% of the events were the result of thermostat changes by staff.  Of these, over 90% were caused by the staff setting the thermostat too low (refrigerator temperature below 1°C), thereby placing vaccine and other medications in immediate peril.  Cold temperatures represent the most significant threat of vaccine loss. Vaccine temperature monitoring could have helped to prevent errors such as these.


Doors left ajar represented the second highest number of staff errors. These errors tended to occur after the end of the day on Friday or Saturday.  Resolution typically took longer as clients were reluctant to go back to the clinic or pharmacy after hours on the weekend.


Non-emergency Refrigeration equipment replacement (Figure 3) was quite frequent (35%) during the term of the study.  These refrigeration replacements were preemptive and based upon unusual refrigeration temperature patterns and consultation between the client and Vax-Shield. Surprisingly, almost 12% of the replacements were the result of refrigeration temperatures that were consistently too cold.

Figure 3

vaccine temperature monitoring chart

Final Thoughts on Vaccine Temperature Monitoring:

The risk of financial loss to an individual clinic or pharmacy is significant.  Independent clinics and pharmacies need to take steps to ensure that they are adequately protected. Vaccine temperature monitoring is a great way to mitigate risk and avoid vaccine loss.