Are you ever concerned that your kids will get their vaccines too early or too late?
Vaccine intervals are typically based on weeks and “months.” But how long is a month?
For example, if your child needs a booster dose of a vaccine in a month, just how long is that?
Does it depend on which month you are in?
For intervals of 3 months or less, you should use 28 days (4 weeks) as a “month.”
Ask the Experts on Scheduling Vaccines
In general, while we often use calendar months, because it is more convenient, you can use a minimum interval of 28 days or 4 weeks as a full month, as long as we are only counting up to three months.
So a second flu shot after a dose on January 1st could be done as early as January 29th. That’s technically one month (28 days, 4 weeks) later. And no, you wouldn’t have to repeat the second dose if you got it on February 1st, as we are typically worried about the minimum intervals or spacing and not about getting the dose a little late.
For intervals of 4 months or longer, you should consider a month a “calendar month”: the interval from one calendar date to the next a month later.
Ask the Experts on Scheduling Vaccines
And just count calendar months if you are counting more than 3 months. So if you got a vaccine on January 1 and needed another 4 months later, you would return on May 1.
Why switch to using “calendar months” for longer intervals? With longer 28 day intervals, scheduling mistakes will likely be made.
What happens if you get a vaccine a few days too early?
You may even know about the minimum ages or minimum intervals between vaccines, but what happens if your child gets a vaccine just a few days early?
Is There a Grace Period for Getting Vaccines?
Fortunately, in most cases, getting a vaccine just a little early isn’t going to mean that the vaccine dose has to be repeated.
“Doses administered too close together or at too young an age can lead to a suboptimal immune response. However, 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; however, local or state mandates might supersede this 4-day guideline.”
General Best Practice Guidelines for Immunization: Best Practices Guidance of the Advisory Committee on Immunization Practices (ACIP)
That’s because the Advisory Committee on Immunization Practices (ACIP) allows a 4-day grace period for most vaccines. So if your child got their vaccines 3 or 4 days before their 1st birthday, instead of on or after turning 12 months old, they would still count!
It is important to keep in mind that:
day 1 is the day before the day that marks the minimum age or minimum interval for a vaccine.
if a vaccine is given 5 or more days too early, beyond the grace period, then the interval to the next dose starts from the day that invalid dose was given. For example, if the second dose of Hib is given two weeks after the first dose (instead of the minimum 4 weeks), then you don’t repeat this invalid dose in two weeks (four weeks from the first dose), but instead wait an additional four weeks from the invalid second dose
live vaccines must be given at least 28 days apart if they are not given at the same time and the grace period can not be used to shorten this interval
Most importantly, in place since 2002, the grace period protects kids from having to repeat vaccines because of minor vaccine scheduling errors.
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…
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
Vaccines work to prevent at least 2 to 3 million deaths each year worldwide.
Tragically, either because of errors or contamination, vaccines can sometimes actually cause people to get sick.
This can happen when health workers:
use a reconstituted vaccine after six hours – live vaccines can quickly become contaminated if they are kept and used for too long a time
mixup diluents – in addition to using the wrong diluent vaccination tragedies can occur when a dangerous medication is used instead of a vaccine’s standard diluent
improperly handle vaccines – breaking the cold chain
With billions of doses of vaccines being given each year, it is likely not surprising that we see some problems. But when many of those vaccines are being given to kids, even one mishap, especially if it leads to life-threatening complications, is too many.
That’s why many safe guards have been put in place in the manufacturer and distribution of modern vaccines, so that we don’t see these types of vaccine tragedies:
the Cutter Incident, when, in 1955, at least 56 people developed polio and 5 children died after being vaccinated with inactivated polio vaccine that was poorly manufactured by Cutter Laboratories and still contained live polio virus
hepatitis-contaminated yellow fever vaccines – some lots of yellow fever vaccines used in the military in 1942 were unintentionally contaminated with the hepatitis B virus
the Lubeck Disaster – 75 children died and others got tuberculosis in 1929 Germany after there was a mixup between the BCG vaccine and the strain of Mycobacterium tuberculosis that causes tuberculosis. The BCG vaccine was supposed to be made with a weakened strain of Mycobacterium bovis bacteria instead.
the Bundaberg incident – 12 children died in Australia in 1928 after being given contaminated diphtheria vaccine from a multidose vial without preservative
tetanus contaminated smallpox vaccine in the 1890s and early 20th century
Although vaccines are much safer now, some rare incidents still occur.
Fifteen infants died and 75 children got sick in Syria in 2014 after they received a neuromuscular blocking agent, atracurium, instead of the measles vaccine they were supposed to get. How? The measles vaccine that was being used is mixed with a diluent, but instead of using the proper diluent, the health worker unintentionally used a bottle of atracurium instead.
In 2015, at least two kids died and 29 got sick in Chiapas, Mexico, among 52 children who were vaccinated. The children were reportedly given a BCG vaccine, the rotavirus vaccine, and/or a hepatitis B vaccine that day. However, the only vaccine that all of the sick children received in common was the hepatitis B vaccine. Since 130,000 doses from the same batch of vaccines had been given in the area, it was not thought to be a manufacturing problem or widespread issue. It was instead bacterial contamination of hepatitis B vaccine vials at that one clinic.
Fifteen children died in 2017 in a village in South Sudan after a poorly trained team that wasn’t adhering to WHO immunization safety standards used the same syringe to reconstitute measles vaccines over a four day period. They also didn’t keep the vaccine vials refrigerated.
“A single reconstitution syringe was used for multiple vaccine vials for the entire four days of the campaign instead of being discarded after single use. The reuse of the reconstitution syringe causes it to become contaminated which in turn contaminates the measles vaccine vials and infects the vaccinated children.”
Statement regarding findings of joint investigation of 15 deaths of children in Nachodokopele village, Kapoeta East County in South Sudan
As you can imagine, the conditions that led to these tragedies aren’t present when most kids get vaccinated.
Even in developing countries, most children get vaccinated by people adhering to WHO immunization safety standards. Why did they happened then? Both Syria and South Sudan have been rocked by war for years, leading to a breakdown in the ability to provide routine health care, even as basic as getting kids vaccinated. And Comunidad La Pimienta, Simojovel, Chiapas is a very poor part of southern Mexico.
These kinds of tragedies aren’t going to happen at your pediatrician’s office, as they don’t even have drugs like atracurium.
What Happened in Samoa?
Two toddlers died after being vaccinated at Safotu Hospital in Samoa.
In Samoa, four years after the deaths of the children in Syria, we are once again hearing about reports of deaths after kids were vaccinated with the MMR vaccine.
Two children in Samoa, both one-year-olds, died within minutes of being vaccinated on the same day in the same hospital on the island of Savai’i.
Not surprisingly, as health officials investigate the cause, use of the MMR vaccine had been suspended in Samoa.
So what happened?
“Until the investigations have been completed and reported on we cannot say what did happen.
However, given the batch of vaccine involved had been in use in that country since August last year, and given the same batch of vaccine has been used in South American countries and the Caribbean island nations without incident, it seems unlikely that there was anything wrong with the vaccine.
The reports from the parents of the children affected on Friday indicate the reactions occurred within minutes after vaccination. This would preclude a response to the vaccine viruses as this takes at least a week. While anaphylaxis occurs within minutes and can be fatal when not treated the odds of seeing this twice in a day at the same place, given a chance of 1 in a million doses, is literally astronomical.”
Dr. Helen Petousis Harrison on What happened in Samoa?
Since it happened so quickly, it sounds like it could have been a mix-up with the diluent, as happened in Syria. A five dose vial of MMR is used in Samoa, which means that unlike premixed vaccines, it does have to be mixed with a diluent.
What about contamination? It is known that vaccine vials can be contaminated with Staphylococcus bacteria if they are mishandled. Although Staphylococcus bacteria can directly cause infections, they can also release a toxin that can cause toxic shock syndrome (TSS).
Considering how quickly these children got died though (within minutes), it isn’t likely that the vaccines became contaminated with Staphylococcus toxins. There have been reports of TSS following vaccination in the past, usually with vaccines that don’t use preservatives, but symptoms typically develop over four to 24 hours.
“This particular vaccine batch lot arrived to Samoa in August 2017 and has been in use since then. The same vaccine batch lot used in Samoa is also in use in a number of South American and Caribbean countries (Belize, Ecuador, St. Vincent, Trinidad Tobago, Chile, Aruba, Dutch Antilles, St. Kitts & Nevis and Cuba) with no reports of adverse events from those countries.”
Could this be related to what happened to two other children in Samoa who had died after getting their MMR vaccines?
Almost certainly not. Those children, siblings, died years earlier, one in 2015 and the other in 2017. Neither died immediately after being vaccinated and there are reports that they may have had some kind of an immunodeficiency syndrome that contributed to their deaths.
“A number of media outlets are already covering these tragic events, speculating on the cause of death before the investigation is completed, and the stories have been picked up by the anti-vaccination movement.”
That some folks would use these rare tragedies to scare parents from vaccinating and protecting their kids is shameful. But that’s the modern anti-vaccine movement…
What to Know About Vaccination Tragedies
Kids shouldn’t get sick or die after getting vaccinated. Fortunately, they rarely do, except in extreme circumstances that can make it more likely for errors to occur.
Although it would be great if mistakes never ever happened, the best we can do is to understand that mistakes do sometimes happen and take steps to avoid them.
How can we avoid mistakes and errors about vaccines?
Avoiding Vaccine Errors
It can help to:
understand the 7 Rights of vaccine administration, including that you give the Right vaccine to the Right patient at the Right time by the Right route at the Right injection site and then follow it with the Right documentation
use a 2d barcoding system with your EMR to help catch vaccine errors before administration
use a screening checklist to help avoid giving vaccines that are contraindicated
double check vaccines that look alike or have names that sound like, such as DTaP and Tdap
double check expiration dates
make sure you aren’t giving live vaccines within 28 days of each other, unless they are given at the same time
make sure you aren’t giving the wrong dosage amount for the patient’s age, as some vaccines have different formulations depending on the age of the patient, including flu shots, hepatitis A, and hepatitis B vaccines
be careful so that you don’t give a combination vaccine, such as Pediarix, Pentacel, Kinrix, Quadracel, or ProQuad, inappropriately
That we are have a 4-day grace period does help avoid the need to revaccinate some kids when vaccines are given a little too early.
“With the exception of rabies vaccine, ACIP allows a grace period of 4 days (i.e., vaccine doses administered up to 4 days before the recommended minimum interval or age can be counted as valid). However, if a dose was administered 5 or more days earlier than the recommended minimum interval between doses, it is not valid and must be repeated. The repeat dose should be spaced after the invalid dose by the recommended minimum interval.”
Ask the Experts About Scheduling Vaccines
In many cases, as long as vaccine doses were administered less than or equal to 4 days before the minimum interval or age, then they can still be counted and are considered valid.
Common Vaccine Errors
It’s easier than you think to prevent vaccine errors.
Especially if there is more than one child in the room getting vaccines, either the tray itself or the vaccines should be labeled with each child’s name so that they don’t get the wrong vaccines. Photo by Vincent Iannelli, MD
When are you most likely to make a vaccine error?
When you are doing something that isn’t routine, which most commonly happens when folks delay or skip some vaccines and are now playing catch-up.
the rotavirus vaccine series must be completed by 8 months (32 weeks)
ProQuad, the MMR and chicken pox combination vaccine, is not licensed for kids who are older than 12 years, although if a teen or adult did get ProQuad, it could be considered an off-label dose and could still count.
Kinrix and Quadracel, the DTaP and polio combination vaccines are only licensed for the 5th dose of DTaP and 4th dose of polio in children who are 4 to 6 years old, so wouldn’t be appropriate for an 18-month-old, even if he needs both (DTaP and polio) vaccines. Earlier doses can sometimes count as off-label doses though.
the combination vaccines Pediarix and Pentacel are only licensed up through age six years, but don’t necessarily need to be repeated if given to older kids.
children and adolescent’s get a pediatric dose (0.5ml) of the hepatitis A vaccine, while older teens, who are at least 19-years-old, get an adult (1.0ml) dose. Since most kids get vaccinated when they are younger, many pediatricians may not have the adult version of the hepatitis A or even realize that there is a different version.
children and adolescent’s get a pediatric dose (0.5ml) of the hepatitis B vaccine, while older teens, who are at least 20-years-old, get an adult (1.0ml) dose. Since most kids get vaccinated when they are younger, many pediatricians may not have the adult version of the hepatitis B vaccine or even realize that there is a different version.
Most importantly, even when giving vaccines on schedule, be sure to triple check everything. This is especially important if multiple kids in the same room are getting immunizations.
Although none of these vaccine errors are very common (hundreds of millions of doses of vaccines are given in the United States each year), understanding which ones occur the most often can help to make sure that they don’t happen in your office.
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.
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)
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?
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.
