Risks of Delaying Vaccines

Some parents consider spacing out or delaying vaccines. We understand the impulse to be cautious — but the evidence is clear that delays increase risk without providing any safety benefit.

Content reviewed against published CDC, AAP, ACIP guidelines

Last reviewed: July 2026 · Editorial policy

Last reviewed:

Key takeaways

  • No major medical organization recommends alternative or delayed vaccine schedules.
  • Delaying vaccines provides no safety benefit — it only extends the time your baby is vulnerable.
  • Studies show children on delayed schedules have higher rates of vaccine-preventable diseases.
  • The CDC schedule is timed to protect babies when they are most vulnerable and most at risk.
  • More visits means more shots total, more stress, and more opportunity for missed doses.

Why Some Parents Consider Delaying

We understand the concerns that lead parents to consider alternative schedules:

  • Worry about "too many vaccines at once" overwhelming the immune system
  • Desire to reduce the number of shots per visit
  • Misinformation suggesting the standard schedule is unsafe
  • A general instinct to "slow down" and be cautious

These feelings are understandable. However, the scientific evidence does not support delayed schedules as safer. Here is why.

What the Evidence Shows

No Safety Benefit to Spacing Out

Multiple large studies have compared children who followed the CDC schedule to those on delayed schedules. There is no difference in adverse events, developmental outcomes, or immune function. The perception that fewer vaccines at once is safer is not supported by data.

Increased Disease Risk

A 2013 study in JAMA Pediatrics found that children with delayed vaccination were significantly more likely to be diagnosed with vaccine-preventable diseases. Every day without vaccination is a day of real vulnerability.

More Visits, More Stress

Spacing out vaccines means more total office visits, more separate needle sticks (since combination vaccines may not be usable), and more cumulative stress for your baby. It also increases the chance of falling behind and missing doses entirely.

The Immune System Is Not Overwhelmed

A baby's immune system encounters and responds to thousands of antigens every single day. The entire childhood vaccine schedule contains fewer than 200 antigens total. Studies confirm that multiple vaccines given simultaneously do not suppress immune function or increase susceptibility to other infections.

Real Risks During the Vulnerability Window

These diseases remain active threats. During any delay, your baby is unprotected against:

  • Pertussis (whooping cough): Kills ~20 US infants/year, mostly under 3 months. 50% of infected infants need hospitalization.
  • Measles: One of the most contagious diseases known. Can cause pneumonia, brain inflammation, and death. 2019 US outbreak had 1,282 cases.
  • Hib meningitis: Before the vaccine, ~20,000 children/year got Hib disease. Can cause brain damage within hours.
  • Rotavirus: Before the vaccine, caused ~50,000 hospitalizations and 20-60 deaths in US children yearly.
  • Pneumococcal disease: Leading cause of bacterial meningitis in children under 2.

What Major Medical Organizations Say

“The recommended immunization schedule is designed to provide protection at the earliest appropriate age. There is no evidence that spreading out or delaying vaccines is safer.”
— American Academy of Pediatrics (AAP)
“The schedule is not random. Each vaccine is given at a specific age based on when children are most at risk and when the vaccine will generate the best immune response.”
— Centers for Disease Control and Prevention (CDC)

Related Vaccine Topics

CDC Schedule

The recommended immunization timeline

Vaccine Safety

How vaccines are tested and monitored

Myths vs. Facts

Debunking common misconceptions

Diseases Prevented

What your baby is being protected from

Frequently asked questions

Is Dr. Sears' alternative vaccine schedule safe?
The AAP, CDC, and AAFP do not endorse any alternative vaccine schedule including Dr. Sears' schedule. There is no scientific evidence that spacing out vaccines is safer. Research shows that alternative schedules leave children unprotected during their most vulnerable period and are associated with increased risk of vaccine-preventable diseases.
Will my pediatrician refuse to see us if we delay vaccines?
Most pediatricians will continue to see your family even if you choose to delay vaccines, though they will strongly recommend following the CDC schedule. Some practices do dismiss families who refuse all vaccines. The AAP recommends that pediatricians continue the relationship and keep educating parents rather than dismissing them.
What if my baby is premature — should I delay vaccines?
No. The AAP and CDC recommend that premature babies follow the same schedule based on chronological (actual birth) age, not adjusted age. Preemies are actually MORE vulnerable to vaccine-preventable diseases, making timely vaccination even more important. The only exception is Hepatitis B for babies under 2,000 grams.
Is it safer to give one vaccine at a time?
No. Studies have found no safety benefit to giving vaccines one at a time. Giving one vaccine per visit means more total office visits, more total needle sticks, more pain and stress for your baby, and — most importantly — longer periods of vulnerability to serious diseases.
What diseases could my baby catch while waiting?
Pertussis (whooping cough) kills approximately 20 babies per year in the US, mostly under 3 months. Measles is highly contagious and can cause brain inflammation. Hib meningitis can cause permanent brain damage within hours. Rotavirus hospitalizes about 50,000 US children yearly. These risks exist every day your baby is unprotected.

Bottom line

There is no scientific evidence that delaying or spacing out vaccines is safer. It only extends the time your baby is vulnerable to serious diseases. The CDC schedule is carefully designed to protect babies at the earliest safe age. If you have concerns, discuss them with your pediatrician — but please do not delay protection.

Wanting to protect your baby from everything is good parenting. The best way to do that is to follow the science-backed schedule that has prevented millions of childhood deaths worldwide.

Our commitment to accuracy

Every page is reviewed against published guidelines from authoritative medical organizations including the CDC, WHO, AAP, ACOG, ASHA, and NIH.

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