With all of the rules for minimum and recommended ages and intervals between doses of vaccines, if you are late with a dose of a vaccine by a few extra days, months, or years, what happens?
Do you ever have to start the series over?
Do You Ever Have to Restart an Immunization Series?
While it is best to follow the recommend schedule when you get your vaccines, fortunately, you usually don’t have to restart an immunization series if you are a little late.
“Q. If a dose of HPV vaccine is significantly delayed, do I need to start the series over?
Ask the Experts about HPV Vaccines
A. No, do not restart the series. You should continue where the patient left off and complete the series.”
Or even a lot late!
“Q. If dose #1 of HPV vaccine was given before the 15th birthday and it has been more than a year since that dose was given, would the series be complete with just one additional dose?
Ask the Experts about HPV Vaccines
A. Yes. Adolescents and adults who started the HPV vaccine series prior to the 15th birthday and who are not immunocompromised are considered to be adequately vaccinated with just one additional dose of HPV vaccine.”
In fact, very rarely would you need to repeat a dose or restart a series of immunizations because of a late dose of a vaccine.
“Prolonged intervals between doses do not appear to diminish and may enhance antibody response to 4vHPV.”
Widdice et al on Antibody responses among adolescent females receiving two or three quadrivalent human papillomavirus vaccine doses at standard and prolonged intervals
And that’s good news, as it is sometimes hard to get folks to complete their immunization series on time.
When You Have to Restart an Immunization Series
There are a few very specific times when a late dose of a vaccine would lead to the need to restart an immunization series though, including the:
- oral typhoid vaccine – if the interruption between doses is less than 21 days, you can resume the schedule without repeating previous doses, but if the interruption is more than 21 days, then you should repeat the series of vaccines
- cholera vaccine (Dukoral only) – if the interval between doses is greater than or equal to six weeks, then you should restart the series
So if you are even a little late getting a dose of oral typhoid or cholera vaccine, then you might have to start the series over. In most other situations, you just continue the series from where you left off, even if it has been years since your last dose.
What about the rabies vaccine?
“If any doses are delayed, vaccination should be resumed, not restarted.”
Rabies vaccines: WHO position paper – April 2018
Although you don’t have to restart the series if you are late with a dose, the CDC does recommend serologic testing 7-14 days after the last dose of rabies vaccine if there are “substantial deviations” to the schedule.
Again, in most other situations, including all of the vaccines on the routine immunization schedule, you just catch-up and continue from where you left off if you are late getting a vaccine dose.
More on Late Doses of Vaccines
- What Are the Recommended and Minimum Ages and Intervals Between Doses of Vaccines?
- Missed Opportunities to Vaccinate
- Why Can’t My 9-Month-Old Get the Rotavirus Vaccine?
- Alternative Immunization Schedules
- Catch-Up Immunization Plans for Adults
- How Do You Get Caught up If You Have Never Been Vaccinated?
- WHO recommendations for interrupted and delayed vaccination now available
- WHO – Table 3: Recommendations* for Interrupted or Delayed Routine Immunization
- WHO – Guide for Rabies Pre and Post Exposure Prophylaxis in Humans
- WHO – Rabies vaccines: WHO position paper – April 2018
- CDC – Perspectives: Alternative Approaches to Rabies Immunization
- IAC – Ask the Experts about hepatitis A Vaccines
- IAC – Ask the Experts about hepatitis B Vaccines
- IAC – Ask the Experts about HPV Vaccines
- Do I Need to Restart the HPV Vaccine If I Missed a Dose?
- IAC – Ask the Experts about Scheduling Vaccines
- IAC – Ask the Experts about Shingles Vaccines
- IAC – Ask the Experts about Meningococcal Vaccines
- Antibody responses among adolescent females receiving two or three quadrivalent human papillomavirus vaccine doses at standard and prolonged intervals
- Adherence to the HPV vaccine dosing intervals and factors associated with completion of 3 doses