Tag: immune system

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.
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.

More on Vaccines While Immunosuppressed

Aren’t Vaccines Made for Adults?

Have you ever heard someone bring up the argument that vaccines are made for adults, so kids shouldn’t be getting the same dosage?

If they do, you should understand right away that they don’t really understand how vaccines work.

And that they really don’t understand immunology either, for that matter.

Are Vaccines Made for Adults?

To be fair, some vaccines are made just for adults. In fact, some, like the shingles vaccines and high-dose flu shot (has four times the amount of antigen in the regular flu shot) are only for seniors.

Other vaccines, like the rotavirus vaccine, are made just for kids.

And a few vaccines come in different forms depending on your age.

For example, younger kids get the DTaP vaccine, while older kids and adults get a Tdap vaccine. They both protect against the same three diseases (diphtheria, tetanus, and pertussis), but they contain different amounts of antigens. In this case, the Tdap vaccine actually contains 3-5 times less of the diphtheria component as the DTaP vaccine. That’s because before they lowered it, repeated dosing of the original Td vaccine every ten years led to worsening local reactions in some people.

The hepatitis B and hepatitis A vaccines are also available in different formulations for kids and adults, with adults getting twice the amount of antigens.

Most other vaccines though, come in the same form for both kids and adults, including the MMR vaccine and vaccines that protect us against HPV, chicken pox, polio, meningococcal disease, and pneumococcal disease, etc.

Are Vaccines Calibrated by Weight or Age?

Why does this question even come up?

Science event in Washington, D.C. reminding folks that Vaccines Work.
Pediatricians at the March for Science event in Washington, D.C. reminded folks that Vaccines Work. We shouldn’t forget that others also need a reminder of how they work.

It’s because some folks push the myth that infants are getting too high a dose of vaccines, since in most cases, older kids and adults get the very same dose.

They don’t though.

Does that mean that those older kids and adults are getting too low a dose then?

Nope.

You see, vaccines aren’t like antibiotics or other medications. They aren’t typically dosed based on your weight or age and don’t have to build up to a steady state in your blood stream.

That’s right, for most vaccines, it doesn’t matter if your child weighs 8 pounds or 80 pounds.

Why not?

Because the antigens in the vaccine don’t have to travel all around your child’s body in order for them to work!

Understanding the Immune Response to a Vaccine

Instead, the small amount of antigens in a vaccine simply get the vaccine response started near where the vaccine was given, whether that is in their arm or leg (shot), nose (nasal), or small intestine (oral).

“B cells are essentially activated in the lymph nodes draining the injection site.”

Claire-Anne Siegrist on Vaccine Immunology

Antigen-presenting cells (APCs) then take up the antigens and migrate towards a nearby lymph node. It is at these lymph nodes that the APCs activate other cells, including:

  • antigen-specific helper T cells
  • killer T cells
  • B cells

The activated T and B cells then go to work, with many B cells becoming plasma cells, and some T and B cells transforming into memory cells.

This illustration from the NIH and National Library of Medicine helps explain how vaccines work.
This illustration from the NIH and National Library of Medicine explains how vaccines work.

Next, within days to weeks of getting vaccinated, the plasma cells begin producing protective antibodies, which are released into our bloodstreams.

The same thing happens if you are exposed to a disease naturally, which is why it is silly to think that a vaccine could weaken or overwhelm your immune system.

The big difference about getting exposed to a disease naturally vs getting a vaccine? With the vaccine, you don’t have to actually have the the symptoms of the disease or any of its complications to get immunity. In other words, you don’t have to earn your immunity.

What to Know About Vaccine Dosage Myths

The dose of vaccines for kids and adults is not calibrated by weight or age because the immune reaction that helps antibodies travel all through your body starts locally, near where the vaccine was given.

More on Vaccine Dosage Myths

Myths About Your Baby’s Immature Immune System

Newborns and infants have immature immune systems, at least as compared to older children and adults.

Premature babies can usually get all vaccines on schedule - at their chronological age, not an adjusted age based on being a preemie.
Premature babies can usually get all vaccines on schedule – at their chronological age, not an adjusted age based on being a preemie. Photo by Vincent Iannelli, MD

That doesn’t mean that their immune system is so immature they they can’t fight off many infections or that they shouldn’t be vaccinated. Even premature babies should usually be vaccinated on time.

Your Baby’s Immature Immune System

So just how immature is their immune system?

“A picture emerges of a child born with an immature, innate and adaptive immune system, which matures and acquires memory as he or she grows.”

Simon et al on Evolution of the immune system in humans from infancy to old age

It is immature enough that the protection that they get from passive immunity and transplacental transfer of antibodies before they are born is considered critical to protect them from many infections.

“After birth, the sudden enormous exposure to environmental antigens, many of them derived from intestinal commensal bacteria, calls for a rapid change to make distinct immune responses appropriate for early life.”

Simon et al on Evolution of the immune system in humans from infancy to old age

Fortunately, their immune system quickly matures and develops, so that as their maternal protection begins to fade, they are “better armed with the maturing innate and adaptive immune systems.”

“The risks are now much reduced by vaccinations, which stimulate protective immune responses in the maturing immune system.”

Simon et al on Evolution of the immune system in humans from infancy to old age

Getting fully vaccinated  on time helps too.

Myths About Your Baby’s Immune Response to Vaccines

Getting vaccinated?

With an immature immune system?

How does that work?

It will likely come as a surprise to some folks, but it actually works quite well!

“Although infants can generate all functional T-cells (ie, Th1, Th2, and cytotoxic T-cells), infant B-cell responses are deficient when compared with older children and adults. Infants respond well to antigens (such as proteins) that require T-cell help for development. However, until about 2 years of age, the B-cell response to T-cell-independent antigens (such as polysaccharides) is considerably less than that found in adults.”

Offit et al on Addressing Parents’ Concerns: Do Multiple Vaccines Overwhelm or Weaken the Infant’s Immune System?

In fact, we know that:

  • newborns respond well to the birth dose of the hepatitis B vaccine
  • the birth dose of BCG vaccine is effective at preventing severe TB disease
  • infants respond well to the vaccines in the primary series that they get at 2, 4, and 6 months
  • while infants respond well to most vaccines, to “circumvent the infant’s inability to mount T-cell-independent B-cell responses,” we use some conjugate vaccines when necessary, like Hib and Prevnar. This is especially important because their immature immune system puts them at extra risk for Hib and pneumococcal disease. Why? These are “bacteria that are coated with polysaccharides.”
  • older infants and toddlers respond to other vaccines, including MMR and the chicken pox vaccine, once maternal antibodies began to fade and can no longer cause interference.

So vaccines work in babies and young infants, just like they do for older children, teens, and adults.

But that makes you wonder, if anti-vaccine folks don’t think that vaccines work in these younger children and that their immune system is so immature, then how can these vaccines overstimulate their immune system???

They don’t.

Both the immunogencity and safety of vaccines for infants are well studied.

What to Know About Your Baby’s Immature Immune System

Vaccines work well to help protect newborns and infants as their immune system continues to develop and mature.

More About Your Baby’s Immature Immune System

Vaccines for Premature Babies

It is easy for the parents of a premature baby in the NICU to get overwhelmed by all of the things that might be going on, especially if they are there long enough for their baby to get their two month vaccines.

Premature babies can usually get all vaccines on schedule - at their chronological age, not an adjusted age based on being a preemie.
Premature babies can usually get all vaccines on schedule, at their chronological age, not an adjusted age based on being a preemie. Photo by Vincent Iannelli, MD

Ventilators, TPN, jaundice lights, feeding tubes, oxygen, apnea monitors, etc. – is this really a time to be thinking about vaccines?

Since premature babies can have an immature immune system and are at greater risk for infectious diseases, including vaccine-preventable diseases, it is actually a great time to make sure that your baby gets vaccinated and protected.

Vaccine Recommendations for Preterm Babies

What vaccines do premature babies need?

Which ones should you delay or skip?

“In the majority of cases, infants born prematurely, regardless of birth weight, should be vaccinated at the same chronological age and according to the same schedule and precautions as full-term infants and children”

ACIP Vaccination of Premature Infants

Not surprisingly, it is recommended that you not delay or skip any vaccine just because your baby was born premature.

You also shouldn’t wait to vaccinate your preterm baby according to any corrected or age-adjusted schedule. Premature babies get vaccinated according to their chronological age, just like everyone else.

There is one exception.

If a preterm baby also has a birth weight less than 2,000g AND their mother is known to be negative for hepatitis B infection, then they can delay their first dose of hepatitis B vaccine until they are 1 month old or at hospital discharge (whichever is sooner). The hepatitis B vaccine can be safely given if the mother is hepB positive or her status isn’t known. That dose just isn’t counted and is later repeated, because of the concern that it might not work as well in low birth weight, premature newborns.

Vaccines Work for Premature Babies

Does that mean that other vaccines for premature babies might not work as well either?

Many studies have shown that vaccines work well in premature babies.

The World Health Organization does recommend that for Prevnar, “pre-term neonates who have received their 3 primary vaccine doses before reaching 12 months of age may benefit from a booster dose in the second year of life.” That doesn’t apply in the United States though, as we give a routine booster to all toddlers at 12 to 15 months and studies have shown this schedule works well for preterm babies. That’s good, because preterm babies are thought to be at much higher risk for invasive Streptococcus pneumoniae infections.

Otherwise, remember the advice of the AAP, including that “medically stable preterm babies weighing more than 4.4 lbs. at birth should be treated like full-term babies and receive the first dose of the hepatitis B immunization according to the recommended schedule.”

What To Know About Vaccines For Your Preterm Baby

Vaccines are safe, effective, and very necessary for premature babies.

More About Vaccines For Your Preterm Baby