Give Vaccines a Well-Deserved Shot: Immunization FAQs - Nemours Blog


Give Vaccines a Well-Deserved Shot: Immunization FAQs

Girl receiving vaccines

Vaccines don’t just protect your kids from illnesses — they protect them from passing the germs on to high-risk populations, like the elderly, babies who are too young to get immunized, kids still in need of their booster shots, children whose immune systems aren’t working well (like those with cancer). As a parent, vaccinating your kids is the safest option for them, your family, and your community.

How do vaccines work?

Getting vaccinated is a way of creating immunity to certain diseases by using small amounts of killed or weakened bacteria (such as pneumococcus) or viruses (like measles) that cause the particular disease. Vaccines cause the immune system to react as if there were a real infection — it fends off the “infection” and remembers the organism so that it can fight it quickly should it enter the body later.

What is community immunity?

Community immunity, or “herd immunity,” is when most of a community is immunized against a contagious disease. Herd immunity helps protect everyone from that disease — even those who can’t be immunized like infants, pregnant women, and people whose immune systems don’t work well — because there is less opportunity for an outbreak. If one person gets a disease, the herd immunity to that disease will help contain it because others in the community will have immunity and are less likely to get and spread the disease to the unvaccinated.

Why immunize?

Knowing that a single child’s chance of catching a disease is low if everyone else is immunized, you may start to think, “Why worry about staying on schedule or bothering with vaccines at all?” But your child is exposed to people other than just those in school. And if one person thinks about skipping vaccines, chances are that others are thinking the same thing. Each child who isn’t immunized gives these highly contagious diseases one more chance to spread.

Although many people are vaccinated in the United States, there’s no reliable way of knowing if everyone your child comes into contact with has been vaccinated, particularly when so many people travel to and from other countries.

Take measles, for example. This highly contagious disease is still common in a number of other countries including Europe, Asia, the Pacific, and Africa. And the U.S is still susceptible to the disease, largely due to travel and people who chose not to vaccinate. All it really takes is one person with measles to travel on a plane to the U.S. for the disease to be reintroduced to a population here.

What are the risks?

The risks associated with vaccinations are very small when compared to the health risks associated with the diseases they’re intended to prevent.

Some people who get vaccines may have mild reactions, such as fever or soreness where the shot was given. And parents may be concerned about their child getting the illness the vaccine is supposed to prevent. But because the components of vaccines are weakened or killed — and in some cases, only parts of the viruses or bacteria are used — they’re highly unlikely to cause any serious illness. Serious reactions are very rare. And immunizations are still one of the best means of protection we have against contagious diseases.

Is there a connection between vaccines and autism?

Over the years, some parents have feared that vaccinations could cause autism spectrum disorder (ASD). But ASD is not caused by vaccines.

Numerous studies by the Centers for Disease Control and Prevention (CDC) and other institutions show there is no relation between vaccines (including the measles, mumps, rubella/MMR vaccine), vaccine ingredients (like thimerosal), and ASD. According to the CDC: “Some people have had concerns that ASD might be linked to the vaccines children receive, but studies have shown that there is no link between receiving vaccines and developing ASD. In 2011, an Institute of Medicine (IOM) report on eight vaccines given to children and adults found that with rare exceptions, these vaccines are very safe.” Read more.

And the original study published by Dr. Andrew Wakefield that suggested a connection between vaccines and ASD has been repeatedly debunked and was retracted by The Lancet, the journal that originally published it, as well as all of its co-authors.

What vaccinations should my child get?

The American Academy of Pediatrics (AAP) recommends that kids get combination vaccines (rather than single vaccines) whenever possible. Many vaccines are offered in combination to help reduce the number of shots a child needs. Getting combination shots or multiple shots in one visit to the doctor is completely safe, and recommended.

The following vaccinations are recommended by the AAP:

Why use a vaccination schedule?

A lot of consideration and research went into creating the immunization schedule used by most doctors. And trying to limit the number of vaccines a child gets at each appointment by spreading them out over more appointments or using an alternative vaccination schedule will increase the time during which your child will be susceptible to diseases that can be prevented. And, because you’ll need to go to the doctor’s office more often, your child could be exposed to more viruses and other illnesses. Moreover, your child will need to get shots more often with an alternative schedule.

You can often get vaccinations as part of routine well-child visits, although many pediatric practices will also make appointments just for vaccinations. Check out the recommended vaccination schedule on the AAP website as well as

Learn More

Kate Cronan, MD

Dr. Cronan is a pediatric emergency attending physician at Nemours Children's Hospital in Wilmington, Del., and a medical editor at Nemours Children’s Health Media.