Category: Immunization Schedules

How Many Doses of Flu Vaccines Do My Kids Need?

One dose or two?

How many doses of flu vaccine will your kids need this year?

That’s right, some kids actually need two doses of the flu vaccine to get the best protection – a priming dose and a booster dose.

How Many Doses of Flu Vaccines Do My Kids Need?

You child might need two doses of flu vaccine, separated by at least 4 weeks, if they are 8 years old or younger and:

this is the first year that they are getting a flu vaccine, or
they have not received two or more total doses of flu vaccine before

That second part is a little confusing.

That’s because the two doses do not have to have been in the same season or even in consecutive seasons. As long as a child has had at least 2 or more doses of flu vaccine in the past, then they only need one dose this year.

And even if they have never had a flu vaccine before, kids who are already 9 years old, only get one dose.

“Evidence from several studies indicates that children aged 6 months through 8 years require 2 doses of influenza vaccine administered a minimum of 4 weeks apart during their first season of vaccination for optimal protection”

Prevention and Control of Seasonal Influenza with Vaccines: Recommendations of the Advisory Committee on Immunization Practices—United States, 2018–19 Influenza Season

Why do they get 2 doses?

“The first dose “primes” the immune system; the second dose provides immune protection.”

Study Looks at Flu Vaccine Dosing in Children

Because studies show that getting 2 doses of flu vaccine like this works best!

Catch-Up Immunization Plans for Adults

It isn’t hard to figure out how to catch-up kids when they fall behind on their vaccines.

After all, the CDC publishes catch-up immunizations schedules for both younger kids and teens.

Catch-Up Immunization Plans for Adults

What happens when an unvaccinated adult needs to get caught up?

Adults need vaccines too, especially if they have never been vaccinated before.

They essentially follow the catch-up immunization plan for teens, with a few exceptions:

the polio vaccine isn’t typically given to teens over age 18
the HPV vaccines aren’t typically given to young adults over age 26
Hib and Prevnar are only typically given to adults with specific conditions that put them at high risk for disease

Are you an adult that needs to get caught up because you have never been vaccinated, your parents skipped or delayed some vaccines, or you lost your immunization records?

Get caught up! It’s likely easier than you think.

Is There a Grace Period for Getting Vaccines?

You know about the standard immunization schedule.

Looking at the latest immunization schedule from the CDC and AAP, it should be clear that kids don't get 69 vaccines. — 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.
the grace period doesn’t apply to the rabies 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
you can’t usually add the grace period to an accelerated schedule
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.

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.

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 Should I Get My Flu Shot?

For most the folks, the real question isn’t if they should get a flu shot, but when.

When Should I Get My Flu Shot?

The original flu shot recommendations were based on the fact that flu vaccine became available for distribution in September, but was not completed until December or January. And that high-risk folks should get vaccinated “to avoid missed opportunities for vaccination” if flu vaccine was available in September and they were already at a doctor’s appointment or in the hospital.

Everyone needs a flu shot. When will you get yours? Photo by Gabriel Saldana (CC BY-SA 2.0)

But for most people, the original recommendation was really that “the optimal time for vaccination efforts is usually during October–November.”

“Persons and institutions planning substantial organized vaccination campaigns (e.g., health departments, occupational health clinics, and community vaccinators) should consider scheduling these events after at least mid-October because the availability of vaccine in any location cannot be ensured consistently in early fall. Scheduling campaigns after mid- October will minimize the need for cancellations because vaccine is unavailable.”

Prevention and Control of Influenza Recommendations of the Advisory Committee on Immunization Practices (2006)

What was the problem with this strategy?

Early flu seasons.

And trying to vaccinate over 100 million people in such a short time.

While it might work fine if flu season doesn’t hit until January or February, waiting until mid-October could leave a lot of folks unvaccinated if you had an early flu season that was peaking in November or December.

Fortunately, we don’t have to rush to get people vaccinated so quickly anymore. For one thing, manufacturers have gotten much better at distributing flu vaccine and are able to get a lot of the doses out at the very beginning of flu season. And with more manufacturers, we are seeing fewer delays and shortages of flu vaccine than we used to.

That’s why the recommendation on the timing of flu vaccination has changed over the years.

“In general, health-care providers should begin offering vaccination soon after vaccine becomes available and if possible by October. To avoid missed opportunities for vaccination, providers should offer vaccination during routine health-care visits or during hospitalizations whenever vaccine is available.”

Prevention and Control of Influenza Recommendations of the Advisory Committee on Immunization Practices (2010)

That nice, simple message has changed yet again though.

To balance the concerns that getting a flu shot too early might leave you unprotected at the end of a late flu season, but getting a flu shot too late might leave you unprotected at the beginning of an early flu season, the latest recommendations from the CDC on the timing of flu vaccination aren’t so clear cut:

Balancing considerations regarding the unpredictability of timing of onset of the influenza season and concerns that vaccine-induced immunity might wane over the course of a season, it is recommended that vaccination should be offered by the end of October.
Community vaccination programs should balance maximizing likelihood of persistence of vaccine-induced protection through the season with avoiding missed opportunities to vaccinate or vaccinating after onset of influenza circulation occurs.
Revaccination later in the season of persons who have already been fully vaccinated is not recommended.
Vaccination should continue to be offered as long as influenza viruses are circulating and unexpired vaccine is available.
To avoid missed opportunities for vaccination, providers should offer vaccination during routine health care visits and hospitalizations.
Optimally, vaccination should occur before onset of influenza activity in the community.
Although vaccination by the end of October is recommended, vaccine administered in December or later, even if influenza activity has already begun, is likely to be beneficial in the majority of influenza seasons.

What’s the problem with these recommendations?

If everyone waits until the end of October to get vaccinated, then you might have a hard time getting a flu vaccine. And you might get stuck if you try and time your flu shot with the onset of flu activity. Unless you have a crystal ball, you don’t know when flu season is going to start.

Still, it is important to note that the CDC doesn’t actually say to wait until the end of October. They say to get vaccinated by the end of October. Getting your kids vaccinated as soon as you can is the best way to make sure that happens.

Could getting a flu shot early leave your kids unprotected at the very end of flu season?

Maybe, but that’s typically when flu activity is low. And we have that same type of low flu activity in early October, well before flu season peaks.

So just remember that your child could end up unvaccinated and unprotected if you mistime their flu vaccine.

What to Know About the Best Time to Get a Flu Vaccine

Experts say to get vaccinated by the end of October. Getting your kids vaccinated as soon as you can is the best way to make sure that happens.

Vaccines While Immunosuppressed

It seems to be a big surprise to many folks, but kids can get most vaccines when they are immunosuppressed. In fact, they sometimes get extra some extra vaccines, like Pneumovax, because the “incidence or severity of some vaccine-preventable diseases is higher in persons with altered immunocompetence.”

They should also get all of their vaccines if they are around someone who is immunosuppressed.

Surprised?

Vaccines While Immunosuppressed

Which vaccines your kids can get while they are immunosuppressed is going to depend greatly on the reason why they are immunosuppressed.

Are they getting chemotherapy?

Did they just get a stem cell transplant?

Were they born with a specific immunodeficiency, like X-linked agammaglobulinemia, selective IgA deficiency, severe combined immunodeficiency, or chronic granulomatous disease?

Whatever the reason, they likely won’t get a medical exemption to skip all of their vaccines.

“Killed vaccines will not cause infection in immunodeficient or any other children. The fear of increased community-acquired vaccine-preventable diseases should lead to adherence to and completion of recommended immunization schedules in the community to reinforce herd immunity, such that all vaccine-preventable diseases become exceedingly rare.”

Recommendations for live viral and bacterial vaccines in immunodeficient patients and their close contacts

In most cases, immunocompromised kids can get all inactivated vaccines. It is only live vaccines that could pose a problem. Even then, it depends on the specific immunodeficiency as to whether avoiding live vaccines is necessary.

For example, after chemotherapy and a stem cell transplant, kids can usually get live vaccines.

Your doctors can review the latest guidelines to come up with a safe vaccination plan for your child with an immune system problem. If necessary, consultation with an infectious diseases or immunology specialist can also be helpful.

Don’t overlook other causes of possible immunosuppression when getting vaccinated, like taking daily oral steroids for more than two weeks, certain biologic immune modulators, or other medications like methotrexate, azathioprine, 6-mercaptopurine.

“Limited evidence indicates that inactivated vaccines generally have the same safety profile in immunocompromised patients as in immunocompetent individuals. However, the magnitude, breadth, and persistence of the immune response to vaccination may be reduced or absent in immunocompromised persons.”

2013 IDSA Clinical Practice Guideline for Vaccination of the Immunocompromised Host

And keep in mind that just because they can and should get vaccinated, it doesn’t mean that their vaccines are going to work as well as in someone who isn’t immunocompromised.

That’s why herd immunity is so important for these kids.

Vaccines for Close Contacts of Immunocompromised People

What about people who come into contacts with kids and adults who are immunocompromised?

Can they get vaccines?

“Close contacts of patients with compromised immunity should not receive live oral poliovirus vaccine because they might shed the virus and infect a patient with compromised immunity. Close contacts can receive other standard vaccines because viral shedding is unlikely and these pose little risk of infection to a subject with compromised immunity.”

Recommendations for live viral and bacterial vaccines in immunodeficient patients and their close contacts

Yes, close contacts can get vaccinated, especially since we don’t use the oral polio vaccine in the United States anymore.

There are some exceptions for the smallpox vaccine, which few people get, and Flumist, but only in very specific situations, including a recent hematopoietic stem cell transplant.

Johns Hopkins Medicine, which includes the Johns Hopkins University School of Medicine and the The Johns Hopkins Hospital and Health System went out of their way to correct this anti-vaccine misinformation.

Worried about shedding?

You should be worried about getting a vaccine-preventable disease and giving it to those around you with immune system problems. That’s the real risk!

This is the modern anti-vaccine movement - taking an immoral stand against vaccines and putting sick kids at risk for life-threatening disease. — This is the modern anti-vaccine movement – scaring parents and taking an immoral stand against vaccines and putting sick kids at risk for life-threatening disease.

And no, you are not being selfish to expect those around you to get vaccinated.

Vaccines are safe and necessary – for all of us.

Vaccines After Cancer and Chemotherapy

Most people know that children being treated for cancer have a suppressed immune system and are at extra risk for vaccine-preventable diseases.

Many children with cancer and other medical conditions benefit from herd immunity. (CC BY 2.0)

That’s one of the reasons that it is important for everyone to be vaccinated, so that herd immunity levels of protection can protect those who can’t get vaccines.

Vaccines After Cancer and Chemotherapy

But what happens after they complete their cancer treatments?

“The interval until immune reconstitution varies with the intensity and type of immunosuppressive therapy, radiation therapy, underlying disease, and other factors. Therefore, often it is not possible to make a definitive recommendation for an interval after cessation of immunosuppressive therapy when inactivated vaccines can be administered effectively or when live-virus vaccines can be administered safely and effectively.”

Red Book on Immunization in Immunocompromised Children

After they complete therapy for cancer, whether it is chemotherapy or a bone marrow transplant, many children need to get extra vaccines.

In the UK, for example, 6 months after completing “standard antileukemia chemotherapy,” children get a booster dose of DTaP, IPV, Hib, MenC, and MMR.

Why just a single booster dose?

Because most kids can continue to get non-live vaccines on schedule while they are getting standard chemotherapy. They get a booster dose when they finish chemotherapy because those vaccine doses they got while receiving treatment might not be as effective as usual and typically don’t count as valid doses.

Of course, if they were missing any doses, then they might need extra doses to catch up too.

“Three months after cancer chemotherapy, patients should be vaccinated with inactivated vaccines and the live vaccines for varicella; measles, mumps, and rubella; and measles, mumps, and rubella-varicella according to the CDC annual schedule that is routinely indicated for immunocompetent persons.”

2013 IDSA Clinical Practice Guideline for Vaccination of the Immunocompromised Host

In contrast to those getting standard chemotherapy, if treatment involved a hematopoietic stem cell transplant (HSCT), then these children are essentially revaccinated:

beginning at 6 months after the HSCT, they should get 3 doses of DTaP if they are less than 7-years-old vs a dose of Tdap and 2 doses of Td if they are already 7-years-old
beginning at 3-6 months after the HSCT, they should get 3 doses of Prevnar
beginning at 6-12 months after the HSCT, they should get 3 doses of Hib
beginning at 6-12 months after the HSCT, they should get 3 doses of hepatitis B, followed by postvaccination anti-HBs titer testing
beginning at 6-12 months after the HSCT, they should get 3 doses of IPV
beginning at 6-12 months after the HSCT, they should get 2 doses of a meningocococcal vaccine (if they are already 11 to 18 years old)
beginning at 6-12 months after the HSCT, they should get 3 doses of HPV vaccine (if they are already 11 to 26 years old)
beginning at 12 months after the HSCT, one dose of the Pneumovax vaccine
beginning at 24 months after the HSCT, two doses of MMR
beginning at 24 months after the HSCT, two doses of the chicken pox vaccine
a yearly flu shot

Why not just check titers instead of repeating all of those vaccines?

“protective” concentrations or titers in this population may not be as valid as in healthy children, leaving open the question regarding what levels to use as the basis for revaccination. Furthermore, there are some vaccines for which no serological correlate of protection exists (e.g., pertussis) or for which, in routine practice, it is too difficult to have levels measured (e.g., polio).

Soonie R. Patel et al. on Revaccination of Children after Completion of Standard Chemotherapy for Acute Leukemia

In Canada, they used to check titers at 1, 3, and 5 years after the end of chemotherapy and just vaccinate when titers dropped, but they switched to giving all kids a booster dose, as it works better.

What will your child’s immunization look like after completing treatment for cancer?

Although the specific recommendations will come from your child’s treatment team, they will likely look something like the guidelines included here.

What to Know About Vaccines After Cancer and Chemotherapy

Kids often have to get revaccinated, or at least get booster doses of their vaccines, after completing treatment for cancer.

VAXOPEDIA

How Many Doses of Flu Vaccines Do My Kids Need?

How Many Doses of Flu Vaccines Do My Kids Need?

More on Flu Vaccine Doses for Kids