The Children’s Immunization Schedule

Mom hugging her toddler. The Children's Immunization Schedule

Guidelines have been set for many health issues, and childhood vaccines are not different. The Advisory Committee on Immunization Practices (ACIP) has established a recommended children’s immunization schedule, which has been approved by the Center for Disease Control (CDC), American Academy of Pediatrics (AAP), American Academy of Family Physicians (AAFP), American College of Obstetricians and Gynecologists (ACOG), and the American College of Nurse-Midwives.  This widely accepted and well-studied schedule for childhood vaccines is detailed below.


  • Hepatitis B #1 — Birth
  • Hepatitis B #2 — 1 to 2 months
  • Hepatitis B #3 — 6 to 18 months*

*If a combination vaccine contains Hepatitis B, it is safe and permissible to have four total doses (birth, 2, 4, and 6 months). 


  • Rotavirus #1 –- 2 months
  • Rotavirus #2 — 4 months
  • Rotavirus #3 — 6 months*

*If the Rotarix brand of Rotavirus vaccine is being used, only two doses (2 and 4 months) are given. The other brand, RotaTeq, requires all three doses.

Diphtheria, Tetanus, acellular Pertussis

  • Diphtheria, Tetanus, acellular Pertussis (DTaP) #1 — 2 months
  • DTaP #2 — 4 months
  • DTaP #3 — 6 months
  • DTaP #4 — 15-18 months
  • DTaP #5 — 4 to 6 years
  • Tetanus, Diphtheria, and acellular Pertussis (TdaP) –– 11 to-12 years ; then Td boosters every 10 years and during pregnancy


  • H. influenzae type b (Hib) #1 — 2 months
  • Hib #2 — 4 months
  • Hib #3 — 6 months
  • Hib #4 — 12 to 15 months


  • Inactivated Polio #1 — 2 months
  • Inactivated Polio #2 — 4 months
  • Inactivated Polio #3 — 6 to 18 months
  • Inactivated Polio #4 — 4 to 6 years


  • Measles , mumps, and rubella (MMR) #1 — 12 to 15 months
  • MMR #2 — 4 to 6 years*

*The ACIP also recommends an extra MMR vaccine for all children 6 to 11 months old who are travelling internationally.  These children still need to complete the two dose series after 12 months. 



  • Pneumococcal conjugate vaccine #1 — 2 months
  • Pneumococcal conjugate vaccine #2 — 4 months
  • Pneumoccocal conjugate vaccine #3 — 6 months
  • Pneumococcal conjugate vaccine #4 — 12 to 15 months

Hepatitis A

  • Hepatitis A #1 — 12 to 23 months
  • Hepatitis A #2 — 6 months after Hepatitis A #1


  • Influenza — Annually for children ages 6 months to 18 years* 

*Children under 9 years receiving influenza immunization for the first time require two doses, 4 weeks apart.


  • Meningococcal vaccine: MCV #1 – 11 to 12 years
  • MCV #2 – 16 years
  • Bexsero (meningococcal type B) – 16 to 23 years (for adolescents not at increased risk) This is a two dose series with dosing at least 1 month apart. 


  • Human papillomavirus (HPV) #1 -– recommended for both females and males at 11 to 12 years of age (minimum age: 9 years). Vaccination schedule is determined based on age of first dose.
  • First dose between ages 9-14 years: HPV #2 -– 6-12 months after first dose.
  • First dose at age 15 years or older: HPV #2 -– 1-2 months after first; HPV #3– 6 months after first dose.

These are general guidelines, and the range of acceptable times for giving these vaccines may vary. Other vaccines may be prescribed by your pediatrician based on specific and individual risk factors.

If you will be traveling outside the country, contact your physician regarding special vaccines that are recommended for the area in which you will be traveling.

Any dose not given at the recommended age should be given as a “catch-up” immunization at any subsequent visit when indicated and feasible.

Dr. Greene’s Take on Immunization Timing

I often hear from parents who like to modify their children’s immunization schedules for one reason or another. According to a warning issued in the November 30, 2001, issue of the CDC’s Morbidity and Mortality Weekly Report, when the MMR vaccine and the chicken pox vaccine are given on two separate days less than 30 days apart, kids are 2.5 times more likely to develop a breakthrough case of chicken pox.

This data is based on the experience of 100,000 children. Most providers are aware of it, but there is concern that children might receive vaccines from two different providers. The smallpox vaccine, another live immunization, presents similar problems. The body needs a 30-day period to develop a full immune response (unless the vaccines are given simultaneously, which is fine). The diphtheria, tetanus, and pertussis vaccine; Haemophilus influenzae type B vaccine; either poliovirus vaccine; and hepatitis B vaccine do not appear to cause this type of problem.

The bottom line: the recommended immunization schedule was developed after a great deal of scientific research. It is re-evaluated at least every year as more data becomes available and the Centers for Disease Control and Prevention (CDC) makes any needed updates. There are broad ranges for the timing of vaccines in the schedule, because they have been shown to work safely within those time intervals. However, when we choose to give these vaccines at different times, as a matter of preference or convenience, we leave behind the benefits of all this testing.

A Special Note on Teen Immunization

Data collected by the CDC points to a growing problem: an estimated 35 million teens, in the United States alone, are missing one or more doses of childhood vaccines. This leaves these teens vulnerable to catching preventable infections as adults, when the diseases are often more serious and have greater complications.  

Here are the childhood vaccines most likely to be missing: one or more of the 2 doses of the MMR vaccine, the 3 doses of the Hepatitis B vaccine, the varicella vaccine, and/or the tetanusdiphtheria booster shot. All of these should have been received by age 12. Teenagers may be at increased risk because of missed doses

Many teens are also behind on their adolescent vaccines (those given at age 11 or greater). According to two reports from the American Academy of Pediatrics, many teens are missing their HPV and annual flu shots.  This puts them at increased risk of these diseases. 

Parents typically rely on their pediatrician to keep their children on schedule, and teens are often visiting the doctor less than they did as young children. There is also a general lack of knowledge about teen vaccines. During a national poll done in 2014 by the University of Michigan, over 90% of parents believed their teen was up to date, when in reality, only between 30-40% of the teens had actually received the recommended vaccinations. Staying up to date on vaccines is one of many reasons why it is still important for your adolescent to continue with their annual well checks.   

References and Resources

Dr. Greene is a practicing physician, author, national and international TEDx speaker, and global health advocate. He is a graduate of Princeton University and University of California San Francisco.

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