In this Article

• Why do we need vaccines? What is immunization? What is immunity?
• How can I become immune (protected)?
• Are there different types of vaccines?
• Can I receive multiple vaccinations during one visit to the doctor?
• Are there any dangers to being immunized?
• What reactions are likely after an immunization?
• Who should not receive a vaccine?
• If I am pregnant, which vaccines can I receive?
• What are invalid reasons for postponing vaccination?
• Why do we keep giving vaccines if the numbers of cases of the vaccine preventable diseases are at a record low in the United States?
• Is there any financial help for people who have been injured by vaccines?
• I am a health-care worker. Is there anything different that I need to do compared with non-health-care workers?
• I am planning foreign travel. Do I need any additional vaccinations?
• Where can I find additional information on immunizations?
• Vaccination FAQs Index

Are there different types of vaccines?

There are two major categories of vaccines.

• The first category of vaccine is made from live viruses that have been "attenuated" or weakened so that they usually do not cause the disease (Table 2). In some cases, the vaccine itself does cause the disease. Usually, the disease caused by the vaccine is milder than the natural disease.



• The second category of vaccine, inactivated vaccine, is produced by growing the bacterium or virus in culture and then inactivating it (killing it) by using heat or chemicals (Table 3). These vaccines cannot cause the disease but allow the body to develop immunity. While these vaccines are safer, they do not produce protection as good as that from the live vaccines. These vaccines require multiple doses and often require periodic supplementation.

Can I receive multiple vaccinations during one visit to the doctor?

Simultaneous administration (vaccines given at the same visit but not in the same shot) of most commonly used vaccines does not decrease the response to the vaccines or increase the risk for adverse reactions. The simultaneous administration of vaccines was instituted to increase compliance with recommended immunization schedules. If people have to come back many times to get additional shots, there is an increased chance that they will not get all recommended vaccinations. In children, there are now a few combination shots that contain multiple vaccines in a single shot. None of these are approved for use in adults except the one containing measles/mumps/rubella (MMR). There is an ongoing controversy about giving "too many" vaccines at one time to little children.

Suggested Reading by Our Doctors

• Flu Vaccine - Get the facts about influenza vaccine (flu shot) ingredients, side effects and vaccination effectiveness. Learn who should (children, pregnant women, elderly) and shouldn't get a flu shot.
• Shingles - Read about shingles symptoms (contagious rash), vaccine, causes (chickenpox [varicella] virus, stress), treatment, how it's transmitted and postherpetic neuralgia.
• Childhood Vaccination Schedule - Read our printable children's immunization schedule and learn about vaccines for kids (Hib, polio, DTaP, MMR, HPV, flu, chickenpox, meningitis, rotavirus, pneumonia, hepatitis A and B).

Read more Vaccination FAQs related articles »

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