There’s no doubt that vaccines have saved countless lives. Vaccines prevent more than 2.5 million unnecessary deaths every year.

From smallpox to polio to measles, vaccines have been saving lives for more than 300 years and large-scale vaccine production has helped countless people. In 2014 alone, the U.S. Centers for Disease Control and Prevention estimated that vaccinations would prevent more than 21 million hospitalizations and 732,000 deaths among children born in the last 20 years.

Large-scale vaccine production has helped keep many previously fatal diseases in check. The World Health Organization and the Measles and Rubella Initiative estimates that 17.1 million lives have been saved by the measles vaccination since 2000. Additionally, the number of measles-related deaths decreased 79% between 2000 and 2014 from 546,800 to 114,900.

For all of the good that vaccines can do and all the lives they can save, it’s important that they are stored properly. To ensure that vaccines are stored properly, three important steps are recommended:

• Storing vaccines at the ideal temperature: According to the U.S. Centers for Disease Control and Prevention, frozen vaccines should be stored in a laboratory medical fridge should be stored in the temperature range between -58 degrees and five degrees Fahrenheit.
  The U.S. Centers for Disease Control and Prevention also recommend that refrigerated vaccines should be stored at 40 degrees Fahrenheit (5 degrees Celsius).
  A thermometer’s temperature probe should be put in the center of a biomedical refrigerator or medical fridge freezer with the vaccines. Each vaccine should be labeled clearly and stored in its original packaging.
• Record daily temperatures at the start of the workday: Use a calibrated instrument to regularly check the temperature of your medical freezer or biomedical refrigerator.
  While the temperature of a biomedical refrigerator should be checked first thing in the morning, it should be checked at least twice a day, in the morning and at the end of the work day. Temperatures should be recorded in a log book with dates, times and maybe even the names or initials of the technicians who are checking them.
• Take action when the temperature is out of range: Check the temperature whenever you access the biomedical refrigerator or medical freezer and take action if the temperature is out of the desired range.
  Determine the cause of the less than ideal temperature, adjust the thermostat and keep monitoring the temperature. It’s important to stop using vaccines in that fridge or freezer if the temperature doesn’t return to an acceptable level. Move it to a laboratory freezer or vaccine refrigerator that’s maintaining temperature and document the work to show when the temperature went out of range.

Storing vaccines correctly will help ensure that vaccines continue to help people and save millions of lives every year. Sites like AAP.org lay out the storage requirements of many common vaccines, making easier to know how to store them and what the acceptable temperature levels should be.