As many moms do, Julie Delinsky of Washington, D.C., takes her one-year-old daughter to the doctor for her recommended vaccinations.
"It's protective and preventative in my mind and anything I can do to keep her as safe and healthy as possible," Delinskyy said.
But a new government report obtained exclusively by ABC News has her a bit worried about the efficacy of the immunizations her daughter is getting.
An investigation by the Department of Health and Human Services' Office of the Inspector General (HHS OIG) found that many providers of immunizations meant for low-income children don't store the vaccines at proper temperatures, potentially rendering them ineffective and placing children at risk for contracting serious diseases.
"I'd be very furious if that happened to me," said Delinsky. "I would be furious if my doctors were not storing them properly and so her vaccines were not effective."
Inspectors visited the offices of 45 providers in five states who offered free immunizations as part of the government's Vaccines for Children (VFC) Program. Nationwide, about 44,000 offices and clinics participate in the program. The Centers for Medicare & Medicaid Services pay for the vaccines, and the Centers for Disease Control and Prevention distribute them.
The investigation found that 76 percent of the providers stored the vaccines at temperatures that were either too hot or too cold. They also found that 13 providers stored expired vaccines along with nonexpired vaccines. In addition, they said they found that none of the providers properly managed the vaccines according to VFC program requirements.
"As a result, the 20,252 VFC vaccine doses that we observed during site visits may not provide children with maximum protection against preventable diseases and may be vulnerable to fraud, waste and abuse," according to the report. "These doses were worth approximately $800,000."
The storage problem could potentially lead to less effective vaccines, but doesn't pose a safety risk, the HHS OIG said.
In 2010, about 40 million children received 82 million VFC vaccines at a cost of approximately $3.6 billion, and providers must meet certain requirements for storage and management.
While the report is concerned with vaccines offered under the VFC program, doctors say the government's investigation is an important reminder to all clinicians about the need to properly and carefully store all vaccines.
"We have vaccines delivered probably every week, and vaccines come in these large Styrofoam containers, and that is to keep them cold or frozen depending on the particular vaccine," said Dr. Promise Ahlstrom, who is Delinsky's daughter's pediatrician. She is not involved in the VFC program.
"The temperature has to be monitored throughout the entire time, from the time it leaves the manufacturer to the time it spends in transit to the time it's delivered to the clinic and it's used in the clinic," said Dr. William Schaffner, chair of preventive medicine at Vanderbilt University Medical Center. "We want every dose given to every child to provide the optimum protection as it's intended," he said.
In its report, the Inspector General's Office recommends that CDC take steps to ensure that providers who participate in the VFC program do their jobs.
"We want them to work with the grantees and providers to make sure that they're storing vaccines properly, then put in better inventory control mechanisms so there's less inventory on hand so that creates less chances that vaccines can expire," said Dwayne Grant, the regional inspector general for the Office of Inspector General in Atlanta.
Dr. Anne Schuchat, director of CDC's National Center for Immunization for Immunization and Respiratory Diseases, told ABC News the vaccination program has helped protect many children from preventable diseases, but acknowledged there was a breakdown in the vaccine management process.
"We're doing our root cause analysis right now to try and understand the key factors that lead up to these issues," she said. "There have been changes in the equipment, the refrigerators. There are many vaccines recommended now, and maybe there are more doses being stored in the average office than there used to be."
The CDC says disease rates haven't gone up because of vaccines affected by temperature problems, but they are investigating a rare whooping outbreak in the state of Washington.
Schuchat stressed that parents should still get their children immunized.
"I don't think this is a time for parents to ask their doctors, 'Where are the vaccines stored and can I go look at them?' I think this is a time for parents to remember that vaccines are very important and that keeping your children and yourselves up to date on vaccines is one of the best things you can do for your health," she said.
Ahlstrom, the Washington, D.C. pediatrician, also said parents shouldn't worry too much about it, but said if they are worried, they should ask questions.
"I think that it is probably good for them to address it with their doctors so that they can feel that their mind, that their mind is put at rest," Ahlstrom said.
And as a mother, Delinsky said vaccine safety is something would definitely address if she had any doubts.
"I think it would be a mistake not to check, to ask the questions and to make sure your doctor is taking those precautions. And I mean the onus is on us as the parents to make sure our child is getting what they need."
ABC News' Jim Avila, Brian Hartman and Serena Marshall contributed to this report.