Storage of Vaccines
First of all, before a vaccine can be administered to your child, the vaccine must be delivered from the vaccine manufacturer to your child's doctor's office and stored properly. A lot of attention is paid to how vaccines are transported and stored. Just like food items and other biological products (donated blood and organs), improper transport and storage can cause a vaccine to become inactive or contaminated. Both conditions pose a serious health threat to your children. Getting a contaminated vaccine can cause infection in the blood stream, which may require your child to be hospitalized.
The federal government has devised exact protocols to ensure proper handling of vaccines during transport and storage so that the vaccines are not damaged or contaminated. Vaccines that do not contain live viruses cannot be frozen during transport and subsequent storage. These vaccines must be refrigerated, however. Vaccines that contain live viruses, including the MMR vaccine, the chickenpox vaccine, and the nasal spray form of the flu vaccine that contains weakened flu virus, must be frozen until they are ready to be administered. Federal inspectors routinely visit doctor's offices to ensure that vaccines are stored properly. This system is set up similarly to the health department inspecting restaurant for food safety.
The one exception to this rule is the rotavirus vaccine, which does contain live virus. The rotavirus vaccine comes in premixed, single-dose containers, and this vaccine must be refrigerated instead of frozen during transport and storage, unlike all other vaccines that contain live viruses.
An additional caveat for many live virus vaccines is that these vaccines are often transported and stored in a freeze-dried state to preserve their effectiveness. This means that these vaccines look like dried powder in their freeze-dried state. Before these vaccines can be administered, they must be mixed with a specially designed liquid, called the diluent, to thaw and suspend the powder and activate these vaccines.
While the freeze-dried vaccines must remain frozen during storage, the liquid can be stored at room temperature or in the refrigerator. The diluent must not be frozen or else it would be impossible to mix a frozen block of ice with the dried powder when it is time to activate the vaccine and give the shots.
Each diluent is specifically designed for a particular vaccine. These diluents are not interchangeable, even though they may look similar. If you are concerned about the use of the appropriate diluent for the vaccine, ask your nurse to double-check the diluent while preparing the vaccine for administration.
One exception to the use of the diluent is the Hib conjugate vaccine. Even though the Hib vaccine does not contain live germs, it is also transported and stored in a powder state and must be mixed with a diluent prior to administration.
Many of the vaccines must be protected from prolonged exposure to light during transport and storage. These vaccines can become ineffective when light interacts with the ingredients in the vaccines. The vaccines that must be shielded include the meningococcal vaccine, the MMR vaccine, the chickenpox vaccine, the rotavirus vaccine, and the HPV vaccine. An astute reader may notice that most of the vaccines (but not all) that must be stored in a dark place are live-virus vaccines.
If you are unsure whether your doctor's office is storing vaccines properly, ask the doctor or the nurse to show you where the vaccines are kept in the office. The refrigerator and freezer unit that is used to store medications and vaccines should not contain any food to avoid cross-contamination. A dedicated refrigeration machine should be available for vaccine storage. The temperature of the vaccine refrigerator and freezer should be constantly monitored by a temperature probe that is readily visible at all times. Ideally, an alarm should alert the office staff if the temperature of the refrigeration unit drifts outside of the acceptable range. All office staff working directly or indirectly with vaccines need to be familiar with the proper protocol for vaccine storage.