Vaccines for Babies: How Long Can They Be Delayed? All Organized for You!

Vaccines for Babies: How Long Can They Be Delayed? All Organized for You!

Author: Vaccine Science Wang Teacher, Master of Public Health from Fudan University, former Deputy Chief Physician of the Disease Control Center

When a baby comes into the world, it is equivalent to entering a 'battlefield'. Regardless of the external environment or relatives and friends, for their immature immune systems, they can be a huge 'virus/bacteria bank'. Wearing a helmet and armor can reduce the risk of babies getting hurt (getting sick) on the 'battlefield'. And this helmet and armor are vaccines!

Is It Urgent to Delay Vaccination?

Many parents may feel wronged — it's not that they want to delay, but really 'have no choice'. Baby's illness, going to other places for holidays, vaccine shortage… All these may cause a dose of vaccine to be delayed.

In fact, the human immune system has a certain 'memory', and the vaccines that have been given will not 'expire'. Delaying vaccination delays the time when 'vaccines start to provide protection', without affecting the final protective effect of the vaccine.

How to Make Up for Delayed Vaccinations?

If it's not delayed for too long, it's okay — just make up the incomplete doses, there's no need to start over. As children grow older, their immune function develops more maturely, and the number of doses that need to be made up may be less than the original vaccination program.

However, if the delay is too long, it may lead to some doses being 'overdue' and unable to be made up, increasing the risk of disease. So, unless there are special circumstances, it is not recommended to delay vaccination — early vaccination, early protection.

Recommended Maximum Age for Supplementary Vaccination

The National Immunization Program for Children's Immunization Schedule and Instructions (2021 Edition) provides the following recommended maximum ages for supplementary vaccination:

Hepatitis B Vaccine Dose 1: Within 24 hours after birth. BCG Vaccine: Less than 3 months of age. Hepatitis B Dose 3, Polio Dose 3, DTP Dose 3, MMR Dose 1, JE Live Vaccine Dose 1: Less than 12 months. Meningococcal Group A Dose 2: Less than 18 months. MMR Dose 2, Hepatitis A, DTP Dose 4: Less than 24 months. JE Dose 2, Hepatitis A Inactivated Dose 2: Less than 3 years. Meningococcal Group A and C Dose 1: Less than 4 years. Polio Dose 4: Less than 5 years. DTP, Meningococcal Group A and C Dose 2: Less than 7 years.

Detailed Vaccine Catch-Up Guide

1. Hepatitis B Vaccine — No strict age limit. When making up, interval between Dose 1 and 2 should be ≥28 days, interval between Dose 2 and 3 should be ≥60 days.

2. BCG Vaccine — Must be completed before age 4. Directly make up if <3 months old; if 3 months to 3 years, PPD test required first; no make-up if ≥4 years old.

3. Polio Vaccine — No strict age limit. Children <4 years who haven't received 3 doses should make up 3 doses; children ≥4 years who haven't received 4 doses should make up 4 doses. Interval ≥28 days.

4. DTP/DT Vaccine — DTP must be completed before age 6; DT before age 12. If children ≥6 years have <3 total doses, make up with DT vaccine.

5. Meningococcal Vaccine — Group A should be completed before 24 months. Children ≥24 months should only make up Group A and C, not Group A alone.

6. MMR Vaccine — No strict age limit. Make up 2 doses with interval ≥28 days.

7. JE Live Vaccine — No strict age limit. Make up 2 doses, interval ≥12 months.

8. JE Inactivated Vaccine — No strict age limit. Make up 4 doses with specified intervals.

9. Hepatitis A Vaccine — No strict age limit. If never vaccinated, make up 1 dose live or 2 doses inactivated (interval ≥6 months).

10. Varicella Vaccine — No strict age limit. Make up 2 doses. For ages 1-12, interval ≥3 months; for ages ≥13, interval ≥1 month.

11. Pentavalent/Quadrivalent Vaccine — First 3 doses before 12 months, Dose 4 before 24 months. Only 1 dose given if >12 months old.

12. Rotavirus Vaccine — The strictest! If a dose is overdue, this dose and remaining doses cannot be made up.

13. EV71 (Hand, Foot, and Mouth Disease) Vaccine — Must be completed before age 6. Make up 2 doses, interval ≥28 days.

14-16. Conjugate/Polysaccharide Meningococcal Vaccines — Various schedules apply depending on type.

17. Hib Vaccine — No vaccination after 72 months. Dosing depends on age at first dose.

18. 13-Valent Pneumococcal Conjugate Vaccine — If ≤1 dose within 1 year, make up 2 doses between 1-2 years; if ≤1 dose within 2 years, make up 1 dose after 2 years.

19. HPV Vaccine — All doses should be completed before age 46. Just make up incomplete doses according to schedule.

Friendly Reminder

Vaccine types, schedules, and supplementary vaccination regulations vary by region. Generally, the vaccination clinic's information system will have the schedule set, and the vaccination doctor will remind you if there are missed or delayed vaccinations. Parents do not need to worry particularly.

Review Expert: Zhong Le, Distinct Health Pediatrician, Ph.D. from Xiangya School of Medicine, Central South University, Visiting Scholar at Yale University School of Medicine

References: 1. Vaccination Work Standards (2023 Edition), National Disease Prevention and Control Bureau. 2. National Immunization Program for Children's Immunization Schedule and Instructions (2021 Edition). 3. Instructions for various related vaccines.

The purpose of this article is to provide general health information. Please consult a doctor for personal medical issues.