Tag: intervals

What Are the Recommended and Minimum Ages and Intervals Between Doses of Vaccines?

Most parents likely don’t think about the minimum age or minimum intervals between vaccines, as they just get their kids vaccinated according to the routine immunization schedule.

Things don’t always go according to schedule though…

Recommended and Minimum Ages for Vaccines

After their birth dose of the hepatitis B vaccine, your baby’s next vaccines are usually at two months.

Can you get them earlier?

When necessary, many vaccines can be given earlier and faster than the standard schedule.
When necessary, many vaccines can be given earlier and faster than the standard schedule.

Yes. The minimum age for the first dose of rotavirus, DTaP, IPV, Hib, Prevnar, is 6 weeks.

Some other vaccines can be given earlier than their recommended age too, including:

  • the first MMR vaccine, which can be given as early as age 6 months in certain high risk situations, like traveling out of the country or in an outbreak situation, although this dose will have to be repeated once the child is 12 months old
  • the 4th dose of DTaP, which can be given as early as age 12 to 15 months, as long as at least 4 to 6 months have passed since the third dose
  • the 2nd dose of Varivax, which may be given as early as 1 to 3 months after the first dose
  • the Tdap vaccine, which can be given as early as age 7 years, instead of the more typical 11 to 12 years
  • the HPV vaccine, which can be given as early as age 9 years, instead of the more typical 11 to 12 years

Why would you get a vaccine early?

What if you are going to be traveling just before you infant is going to be 2 months old? Or your 9 year old stepped on a rusty nail, and it had been just over 5 years since his last tetanus (DTaP) shot?

Recommended and Minimum Intervals for Vaccines

In addition to earlier ages, you can sometimes get vaccines more quickly, on an accelerated schedule.

For example:

  • the minimum interval between the 1st and 2nd dose of rotavirus, DTaP, IPV, Hib, Prevnar is 4 weeks, instead of the standard 2 months
  • the minimum interval between the 2nd and 3rd dose of rotavirus, DTaP, IPV, Hib, Prevnar is 4 weeks, instead of the standard 2 months
  • the minimum interval between the 1st and 2nd dose of HPV is either 4 weeks (3 dose schedule) or 5 months (2 dose schedule)
  • the minimum interval between the 2nd and 3rd dose of HPV is 12 weeks
  • the minimum interval between the 1st and 3rd dose of HPV is 5 months, instead of the standard 6 months

Why give these vaccines more quickly than usual?

The usual reason is that a child is a little behind and is working to get caught up.

Absolute Minimum Ages for Vaccines

It is important to remember that in some cases, there are some hard and fast rules about minimum ages. That means that if you get these vaccines any earlier, they won’t count and you will likely have to repeat them, including getting :

  • the 3rd dose of hepatitis B before 6 months (24 weeks) or sooner than 8 weeks after 2nd dose and  16 weeks after 1st dose
  • the first dose of MMR, Varivax or hepatitis A before 12 months
  • the 4th dose of Hib before 12 months
  • the 4th dose of Prevnar before 12 months
  • the 4th dose of DTaP before 12 months
  • the 5th dose of DTaP before 4 years
  • the 4th dose of IPV before 4 years

Sticking to the routine schedule helps to avoid vaccine errors, like giving a vaccine too early. In some situations, the 4 day grace period helps if a vaccine is given a little early.

More on Recommended and Minimum Ages and Intervals Between Doses of Vaccines

When a Vaccine Doesn’t Count and Needs to Be Repeated

Of course, anti-vaccine folks are wrong when they say that vaccines don’t work.

Vaccines work and they work well to protect us from many different vaccine preventable diseases.

At least they do when you get the right vaccine at the right time and it is given properly. If an error is made, sometimes a vaccine dose needs to be repeated.

When a Vaccine Doesn’t Count and Needs to Be Repeated

While it would be unfortunate to have to repeat a vaccine dose, in most cases, if you didn’t, it would leave the child without full protection.

Why might a vaccine dose not count?

The Menomune vaccine has been discontinued, but this label is a good example of things to check before giving a vaccine.
The Menomune vaccine has been discontinued, but this label is a good example of things to check before giving a vaccine.

Although it doesn’t happen often, it is possible that:

  • the wrong vaccine was given
  • the vaccine was given too early, either before the next dose was due or when the child was too young. Although there is some leeway for when most vaccines can be given, there are still some specific rules to follow, especially the minimum time between doses, the earliest age you can get a dose, and the age requirement for booster doses. (sticking to the standard immunization schedule can help avoid these types of errors)
  • the vaccine was mixed improperly (many vaccines are now premixed, making this error less likely to occur)
  • part of the vaccine leaked out when it was being injected, which can happen when kids move, if they aren’t being held well as the shot is being given (rotavirus doses aren’t repeated if a child spits up though)
  • the vaccine had expired or had not been stored properly
  • two live vaccines (except for the typhoid vaccine) were given on separate days, but less than 28 days apart (again, sticking to the standard immunization schedule can help avoid this types of error)
  • the vaccine was given by the wrong route, although depending on the vaccine, this dose might still be valid (most vaccines, except hepatitis B and rabies)

Still, instead of a vaccine dose not counting, the much more common reason for a vaccine dose to be repeated is for folks to lose their vaccine records.

Do You Really Have to Repeat That Vaccine Dose?

Are you worried now that your kids might get a vaccine dose that has to be repeated?

Don’t be. It doesn’t happen very often.

It helps that we don’t actually have a one-size-fits-all immunization schedule and

  • there is a range of recommended ages for most vaccines
  • there is a range of recommended ages for catch-up immunization, which is basically an accelerated immunization schedule, which is why infants can typically start getting their vaccines as early as age 6 weeks and get the first few sets as early as 4 weeks apart

Also, you typically have a grace period, during which early vaccine doses will still count.

“…administering a dose a few days earlier than the minimum interval or age is unlikely to have a substantially negative effect on the immune response to that dose. Known as the “grace period”, vaccine doses administered ≤4 days before the minimum interval or age are considered valid…”

AICP on Timing and Spacing of Immunobiologics

The grace period doesn’t count for the rabies vaccine and while it is an ACIP guideline, it might be superseded by local or state mandates. The grace period also can’t be used to shorten the interval between two live vaccines, which must be at least 28 days.

One last way to get away without repeating an invalid dose would be checking your child’s titers.

When Do You Repeat the Invalid Vaccine Dose?

The next question that comes up after you realize that you have to repeat a dose of a vaccine is when should you repeat it?

It depends.

  • give the correct vaccine as soon as possible if the problem was that the wrong vaccine was given
  • repeat the dose as soon as possible if the problem was an expired, improperly stored, or a dose that had leaked out
  • if the dose was given too early, then you need to wait for the appropriate interval or when your child is old enough to get the dose. Keep in mind that when you repeat the dose, you would generally restart counting your interval from the invalid dose, not from the previous dose. That’s because the invalid dose might interfere with mounting a good immune response.

And in all cases, report the error to the ISMP National Vaccine Errors Reporting Program (VERP) or VAERS.

What to Know About Vaccine Errors

Although they aren’t common, vaccine errors sometimes lead to the need to repeat your child’s vaccines.

More on Vaccine Errors