Common Questions About Vaccines

Yes. Vaccines are very safe. The United States’ long-standing vaccine safety system ensures that vaccines are as safe as possible. Currently, the United States has the safest vaccine supply in its history. Millions of children safely receive vaccines each year. The most common side effects are very mild, such as pain or swelling at the injection site.

Vaccines can prevent infectious diseases that once killed or harmed many infants, children, and adults. Without vaccines, your child is at risk for getting seriously ill and suffering pain, disability, and even death from diseases like measles and whooping cough. The main risks associated with getting vaccines are side effects, which are almost always mild (redness and swelling at the injection site) and go away within a few days. Serious side effects after vaccination, such as a severe allergic reaction, are very rare and doctors and clinic staff are trained to deal with them. The disease-prevention benefits of getting vaccines are much greater than the possible side effects for almost all children. The only exceptions to this are cases in which a child has a serious chronic medical condition like cancer or a disease that weakens the immune system, or has had a severe allergic reaction to a previous vaccine dose.

No. Scientific studies and reviews continue to show no relationship between vaccines and autism.

Please see the CDC vaccine safety website for more information on autism and vaccines.

Vaccines, like any medication, may cause some side effects. Most of these side effects are very minor, like soreness where the shot was given, fussiness, or a low-grade fever. These side effects typically only last a couple of days and are treatable. For example, you can apply a cool, wet washcloth on the sore area to ease discomfort.

Vaccines do not overload the immune system. Every day, a healthy baby’s immune system successfully fights off thousands of germs. Antigens are parts of germs that cause the body’s immune system to go to work to build antibodies, which fight off diseases.

The antigens in vaccines come from the germs themselves, but the germs are weakened or killed so they cannot cause serious illness. Even if babies receive several vaccinations in one day, vaccines contain only a tiny fraction of the antigens they encounter every day in their environment. Vaccines give your child the antibodies they need to fight off serious vaccine-preventable diseases.

The recommended schedule protects infants and children by providing protection early in life, before they come into contact with life-threatening diseases. Children receive vaccinations early because they are susceptible to diseases at a young age.

Talk with your child’s doctor, but children can usually get vaccinated even if they have a mild illness like a cold, earache, mild fever, or diarrhea. If the doctor says it is okay, your child can still get vaccinated.

Children do not receive any known benefits from following schedules that delay vaccines. Infants and young children who follow immunization schedules that spread out or leave out shots are at risk of developing diseases during the time you delay their shots.

Young children have the highest risk of having a serious case of disease that could cause hospitalization or death. Delaying or spreading out vaccine doses leaves your child unprotected during the time when they need vaccine protection the most. For example, diseases such as Hib or pneumococcus almost always occur in the first 2 years of a baby’s life. And some diseases, like hepatitis B and whooping cough (pertussis), are more serious when babies get them.

Yes, even breastfed babies need to be protected with vaccines at the recommended ages. The immune system is not fully developed at birth, which puts newborns at greater risk for infections.

Breast milk provides important protection from some infections as your baby’s immune system is developing. For example, babies who are breastfed have a lower risk of ear infections, respiratory tract infections, and diarrhea. However, breast milk does not protect children against all diseases. Even in breastfed infants, vaccines are the most effective way to prevent many diseases. Your baby needs the long-term protection that can only come from following CDC’s recommended schedule.

No, even young children who are cared for at home can be exposed to vaccine preventable diseases, so it’s important for them to get all their vaccines at the recommended ages. Children can catch these illnesses from any number of people or places, including from parents, brothers or sisters, visitors to their home, on playgrounds or even at the grocery store. Regardless of whether your baby is cared for outside the home, your baby comes in contact with people throughout the day, some of whom may have a vaccine-preventable disease.

Many of these diseases can be especially dangerous to young children, so it is safest to vaccinate your child at the recommended ages.

No. Before entering school, young children can be exposed to vaccine-preventable diseases. Children under age 5 are especially susceptible to diseases because their immune systems have not built up the necessary defenses to fight infection.

Vaccines are recommended throughout our lives to protect against serious diseases. As protection from childhood vaccines wears off, adolescents need vaccines that will extend protection. Adolescents need protection from additional infections as well, before the risk of exposure increases.

Getting every recommended dose of each vaccine provides your child with the best protection possible. Depending on the vaccine, your child will need more than one dose to build high enough immunity to help prevent disease or to boost immunity that fades over time. Your child may also receive more than one dose to make sure they are protected if they did not get immunity from a first dose, or to protect them against germs that change over time, like flu. Every dose is important because each protects against an infectious disease that can be especially serious for infants and very young children.

Babies may get some temporary protection from mom during the last few weeks of pregnancy, but only for diseases to which mom is immune. Breastfeeding may also protect your baby temporarily from minor infections, like colds. These antibodies do not last long, leaving your baby vulnerable to disease.