Vaccine Information Raleigh NC

1. What is the difference between the innate and adaptive immune system?

   The innate immune system is designed to provide a kind of "shock and awe" protection against bacteria, viruses and other pathogens. When cells in the innate immune system "see" an invader, they rush in to destroy it, often by releasing inflammatory chemicals like histamines and leukotrienes. These invaders display "signs" on their surface called antigens that signal immune system cells to action.

   The adaptive immune system provides a more targeted approach. As immature T and B lymphocytes encounter antigens, they develop specific antibodies against those antigens. These "mature" lymphocytes hang out in tissue, ready to quickly spring to action when they encounter the same antigens. This creates immunologic memory and prevents reinfection.

2. How do vaccines work?

   All vaccines are designed to affect the immune system in some way. Prophylactic vaccines are designed to stimulate a response of the adaptive immune system to a modified version of the pathogen so that when you are infected with the actual virus or bacteria, it can quickly mount a major offense against the invader before you become sick. Therapeutic vaccines are designed to strengthen the immune system's response to a cancer or other abnormal cell.

3. What is the difference between live and "killed" vaccines?

   Live, attenuated vaccines contain a live, although significantly weakened, version of the virus or bacteria. Measles, mumps and chicken pox vaccines are made with live viruses. The benefit of a live vaccine is that a single dose often provides lifelong immunity. The downside is that because viruses and other pathogens naturally mutate, or change, the virus within the vaccine could also change, creating a more virulent version of itself that the immune system would have difficulty combatting. This was an issue with the early oral polio vaccines, but is generally not a problem with current live vaccines, which are much safer than the virus they protect against. Only people with a suppressed immune system (such as those who have HIV, are taking immunosuppressant drugs or are being treated for cancer) should be concerned about receiving live vaccines because they could, conceivably, become infected with the virus. These vaccines also usually require refrigeration.

   Inactivated vaccines contain a killed version of the pathogen. They are more stable (meaning they don't need refrigeration) and safer than attenuated viruses, but they don't elicit as strong an immune response. Thus, the immunity they provide may not last as long and you might need a "booster" vaccine down the road.

4. What types of vaccines protect against bacterial infections?

   Typically toxoid vaccines. Many bacteria secrete toxins that damage healthy cells. Toxoid vaccines treat the bacteria with formalin, which renders the toxins harmless but still retains enough of their structure to "teach" immune cells to recognize the bacteria and train them to lock onto the toxin antigen before the bacteria can release it. Toxoid vaccines are used for diphtheria and tetanus. Conjugate vaccines are also used in young children.

5. What should I do if my child misses a vaccine?

   Call your health care professional. Children can "catch up" on nearly all vaccines, regardless of their age.

6. What vaccines do adolescents require?

   Preteens and adolescents should receive vaccines against the human papillomavirus (girls only); meningococcal disease; whooping cough; influenza; hepatitis B; mumps/measles/rubella; polio; tetanus/diphtheria/acellular pertussis (Tdap); and varicella (chicken pox), depending on what vaccines they received when they were younger.

7. I'm traveling out of the country. What vaccines do I need?

   Make an appointment with your health care professional at least four to six weeks before your trip to see if you need any travel-related vaccines. The only required vaccines are yellow fever for those traveling to countries in sub-Saharan Africa and tropical South America and the meningococcal vaccine for travel to Saudi Arabia during the Hajj. You can learn more about vaccines required for overseas travel at the Centers for Disease Control Web site. Your local health department can typically provide the vaccines.

8. I'm worried about the safety of vaccines.

   Vaccines are extremely safe. The Centers for Disease Control and Prevention operates an Immunization Safety Office that continuously monitors vaccine safety, including side effects. Part of its mission is managing the vaccine adverse event reporting system, which serves as an "early warning" system to detect vaccine-related problems. About 30,000 reports are filed annually, but just 10 to 15 percent are classified as serious (causing disability, hospitalization, life-threatening illness or death). Anyone can file a report, including health care providers, manufacturers, personal injury lawyers and vaccine recipients or their parents or guardians.

9. I heard that vaccines can cause autism.

   Some parents insist that their children developed autism after having early childhood vaccines, such as the measles/mumps/rubella (MMR) vaccine. Some suspect that a preservative once used in childhood vaccines that contained mercury caused autism. But numerous scientific investigations regarding a possible link found no connection. Today's childhood vaccines do not have mercury-based preservatives; nonetheless, autism rates have continued to rise.

10. I have breast cancer. I heard there is a vaccine that can treat the cancer. How can I find out more?

    There are several vaccines under investigation for cancer. These are called therapeutic vaccines because they are designed to treat, rather than prevent, disease. However, none have been approved yet. So talk to your doctor about joining a clinical trial. You can find information about clinical trials for breast cancer vaccines at www.clinicaltrial.gov.

For the rest of this article, questions to ask your health care professional, information on diagnosis, treatment, prevention and more, click here.

Author: Editorial Staff of the National Women's Health Resource Center