Keeping track of your little one’s vaccinations can seem daunting: Knowing which vaccine is for what, and remembering what they need when, is enough to confuse anyone. Keep in mind, though, that the diseases vaccines protect against, like chickenpox, whooping cough and even polio, still exist and could threaten your child’s health.

For adults, diseases can be miserable. For children, it can be life threatening because the immune system is not fully developed yet.

“For children that are transitioning from preschool and on to elementary school, they’re going to be around a lot of other kids for the first time and being exposed to communicable diseases,” said Dr. Matt Jaeger, pediatric emergency medicine physician at The Children’s Hospital at TriStar Centennial. “In the middle school age-range, kids need boosters because some of these vaccines require follow-up for life-long prevention.”

High vaccine rates are important to provide herd immunity.

“Immunizations are developed for diseases that have very severe complications and in years past, were very prevalent,” said Dr. Jaeger. “Individually, children not getting a vaccination are at serious risk for picking up on the disease. For the community at large, diseases can come back at higher numbers than they have been in past years.”

Dr. Jaeger encourages scheduling an appointment with your pediatrician to discuss what vaccinations are recommended by the American Academy of Pediatrics and the CDC.

Hepatitis A and B

Why vaccinate: Both hepatitis A and hepatitis B are liver diseases, but they are caused by different viruses. Hepatitis A is an acute infection that can last from a few weeks to a few months. Hepatitis B can cause a lifetime of serious and sometimes fatal conditions like cirrhosis, liver cancer and liver failure. And, the younger kids are when they get hepatitis B, the more likely it will become chronic. About 90% of ;all infected infants will develop a chronic infection.

When to vaccinate: Starting at age 12 months, your child should receive the hepatitis A vaccine in two doses, six months apart. The hepatitis B vaccine is the only vaccine that is given at birth, before your baby is discharged from the hospital. After that, he should get two more doses by the time he is 18 months old.

Risks: Most babies don’t have reactions to either of these vaccines.

Rotavirus

Why vaccinate: Rotavirus diarrhea usually occurs in babies and young children. In some cases, it can cause dehydration, vomiting and/or a fever.

When to vaccinate: The first dose should be given no later than 15 weeks. Doctors recommend the doses occur at 2 months, 4 months and six months.

Risks: Most babies won’t experience any side effects. But it’s important to note that the vaccine does not prevent diarrhea caused by other germs. In rare cases, serious side effects such as intussusception and allergic reactions may occur. Babies with a weakened immune system, or rare conditions like severe combined immunodeficiency (SCID) or who have had intussusception should not get the vaccine.

Diphtheria, Tetanus and Pertussis (DTaP)

Why vaccinate: All three are serious, sometimes fatal, diseases triggered by bacteria. Diphtheria, a dense, gray coating in the nose throat or airway, may cause breathing complications, paralysis or heart failure. Tetanus causes lockjaw and/or muscle spasms. Pertussis (a.k.a. whooping cough) causes convulsive coughs that can last for up to 10 weeks.

When to vaccinate: Kids need a total of five doses, starting when they’re 2 months and again at 4 months, 6 months, 15 to 18 months and 4 to 6 years old. Older kids are not eligible for DTaP; instead, kids age 11 and up can receive the Tdap vaccine, which protects against diphtheria, tetanus and pertussis.

Risks: Contracting any of the diseases is much worse than getting the vaccine itself. About 25% of kids may experience a fever or redness or tenderness at the injection site.

Haemophilus Influenzae Type B (Hib)

Why vaccinate: The bacterium Hib may cause everything from mild ear or skin infections to serious conditions like meningitis or pneumonia. It can be deadly or, in some cases, cause lifelong disabilities.

When to vaccinate: The Centers for Disease Control and Prevention (CDC) recommends the Hib vaccine for all kids ages 5 and younger. Ideally, infants will receive doses at 2 months, 4 months, 6 months and between 12 and 15 months.

Risks: Kids who’ve experienced a severe allergic reaction to one dose of Hib should not get another. And kids who are really sick should wait until they are better before getting the shot.

Pneumococcal Disease

Why vaccinate: Pneumococcal disease may cause meningitis, pneumonia and painful ear infections.

When to vaccinate: Children should get four doses of the PCV13 vaccine, spanning from ages 2 months to 15 months. If your child has a high risk of the disease, he should also get the PPSV23 vaccine starting at age 2.

Risks: PCV13 does not cause serious reactions. Some children may experience tenderness or swelling at the injection site or drowsiness, loss of appetite and a fever.

Remember: Starting at 6 months, your child should get the flu shot every year, which can also decrease his chances of contracting pneumococcal disease.

Poliovirus

Why vaccinate: The poliovirus, usually found in the throat and intestines, may cause flu-like symptoms, a stiff neck and/or pain in the limbs. In rare cases, it can cause paralysis.

When to vaccinate: Children should get four doses of the inactivated poliovirus vaccine (IPV) at 2 months, 4 months, 6 to 18 months, and 4 to 6 years of age.

Risks: Your child should not get the vaccine if he is allergic to any part of the IPV. Like other vaccines, if your child is moderately or extremely sick, he should wait to get vaccinated until he’s feeling better.

Measles, Mumps, Rubella (MMR)

Why vaccinate: Measles may cause a rash or cold-like symptoms, and could trigger an ear infection, pneumonia or seizures. Mumps may cause muscle pain and swollen glands, and could lead to meningitis or even deafness. Rubella may cause a rash or even arthritis.

When to vaccinate: Children should get two doses of the MMR vaccine, starting at age 12 to 15 months and again when they’re 4 to 6 years old. If you are traveling abroad and your baby is under one year old, she may get the vaccine, but it will not count as part of her routine vaccination.

Risks: According to experts, it’s much safer to get the vaccine than to risk getting any of these diseases.

Varicella

Why vaccinate: Also known as chickenpox, varicella is a highly contagious disease that causes an itchy, uncomfortable blister-like rash on the skin. While the disease is normally mild, it can be serious in babies or adults.

When to vaccinate: Children should get the two-dose vaccine at 12 to 15 months and again at 4 to 6 years. There’s also a combination vaccine called MMRV, which contains both the MMR and chickenpox vaccines. If your child got the MMRV vaccine, he does not need to get the varicella vaccine.

Risks: Most children do not experience any problems with this vaccine—just soreness or swelling.

Human Papillomavirus (HPV)

Why vaccinate: HPV is considered a sexually transmitted infection (STI) -- but it’s important to vaccinate your kids now, so their bodies can build immunity against the disease before they become sexually active. Each year, about 17,500 women and 9,300 men in the US have HPV-related cancers that could have been prevented by the HPV vaccine.

When to vaccinate: Kids should get the three-dose HPV vaccine starting at age 11 or 12. Women and most men can get the vaccine until they are 27 years old.

Risks: Side effects are pretty rare, but some may experience mild pain at the injection site or fever, headache and joint or muscle pain.

Meningococcal Disease

Why vaccinate: Meningococcal disease is a serious bacterial infection that usually causes meningitis, but can also cause a blood infection. About 1 in 10 people who get the disease die from it, and others may have serious disabilities. It’s especially common in infants less than one year of age and people age 16 to 21, such as college students who live in a dorm.

When to vaccinate: Adolescents usually get the first dose of meningococcal vaccine at age 11 or 12, with a booster when they’re 16.

Risks: Soreness or redness at the injection site is common, but lasts just a day or two. Allergic reactions are very rare.

Print off this vaccination chart from our partners at the Centers for Disease and Control.

This content originally appeared on Sharecare.com.