Tag: immune system

Did Dr. Bob Uncover a CDC Plot to Give Adult Flu Shots to Babies?

Have you heard the news?

Uh, the ACIP can't request a license for a vaccine...
Uh, the ACIP can’t request a license for a vaccine…

Dr. Bob and his new podcasting side kick think that the “CDC wants the FDA to approve adult doses of the flu vaccine for babies, because the normal half-doses approved for babies don’t work well enough.”

Did Dr. Bob Uncover a CDC Plot to Give Adult Flu Shots to Babies?

This is likely going to surprise Dr. Bob, but many infants already get the same dose of flu vaccine as adults.

Both FluLaval and Fluarix are given at the same 0.5ml dose, containing 15 µg of HA per vaccine virus, to infants, older children, and adults.

Fluzone, on the other hand, is still given at a 0.25ml dose, containing 7.5 µg of HA per vaccine virus, to children between the ages of 6 months to three years, and a larger 0.5ml dose to older kids and adults.

Why the differences?

“In a randomized trial comparing immunogenicity and safety of 0.5 mL FluLaval Quadrivalent with 0.25 mL Fluzone Quadrivalent, safety and reactogenicity were similar between the two vaccines.”

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

Because they are just as safe at the lower doses and might actually work better.

Then why did we ever use a lower dose for infants?

That recommendation was based on the older, whole-virus version of the flu shot, which did cause more side effects for infants when given at a full dose. We now use split-virus flu shots that don’t have this problem.

And now, the manufacturer of Fluzone has done a study, and not surprisingly, they have also found that “safety profile of a 0.5 ml (full-dose) is similar to 0.25 ml (half-dose) and may be more immunogenic.”

So they are submitting a BLA to the FDA for the use of the 0.5ml dose of their flu vaccine for infants.

What about the idea of an “adult dose of mercury” for infants?

Over 80% of flu vaccines were thimerosal free this year. You almost have to go out of your way to get your kids a flu vaccine with thimerosal, so no, this won’t mean an “adult dose of mercury” for your infant.

Most importantly though, if you understand how vaccines work, you know that the dose of vaccines for kids and adults is not calibrated by weight or age, so none of this really matters. The immune reaction that helps antibodies travel all through your body starts locally, near where the vaccine was given, so a 20-pound infant and a 200-pound adult can get the same dose of flu shot and both can be protected.

More on Dr. Bob’s CDC Plot to Give Adult Flu Shots to Babies

Is Surgery a Contraindication to Getting Vaccinated?

There are some situations in which it is very important to think about vaccines before your child has surgery.

“Pneumococcal conjugate vaccine (PCV13, Prevnar 13, Pfizer), Haemophilus influenzae type b vaccine (Hib), meningococcal conjugate vaccine (MenACWY), and meningococcal B vaccine should be given 14 days before splenectomy, if possible.”

Ask the Experts about Scheduling Vaccines

A splenectomy leaves your child at extra risk for many vaccine-preventable diseases, so it is a good idea to get vaccinated and protected well in advance of a planned splenectomy, if possible.

This doesn’t mean that these vaccines won’t work after the surgery, but just that you don’t want your child to be unprotected while he remains unvaccinated.

Is Surgery a Contraindication to Getting Vaccinated?

What about other surgeries?

Some kids are put on an aspirin regimen after cardiac surgery and it should be noted that taking aspirin is a contraindication for getting FluMist, the nasal spray flu vaccine, and is considered a precaution for getting the chicken pox vaccine.

“(j)No adverse events associated with the use of aspirin or aspirin-containing products after varicella vaccination have been reported; however, the vaccine manufacturer recommends that vaccine recipients avoid using aspirin or aspirin-containing products for 6 weeks after receiving varicella vaccines because of the association between aspirin use and Reye syndrome after varicella. Vaccination with subsequent close monitoring should be considered for children who have rheumatoid arthritis or other conditions requiring therapeutic aspirin. The risk for serious complications associated with aspirin is likely to be greater in children in whom natural varicella develops than it is in children who receive the vaccine containing attenuated VZV. No association has been documented between Reye syndrome and analgesics or antipyretics that do not contain aspirin.”

Vaccine Recommendations and Guidelines of the ACIP

In most other situations, not only is surgery not considered a contraindication to getting vaccinated, but “hospitalization should be used as an opportunity to provide recommended vaccinations.”

“Most studies that have explored the effect of surgery or anesthesia on the immune system were observational, included only infants and children, and were small and indirect, in that they did not look at the immune effect on the response to vaccination specifically. They do not provide convincing evidence that recent anesthesia or surgery significantly affect response to vaccines. Current, recent, or upcoming anesthesia/surgery/hospitalization is not a contraindication to vaccination. Efforts should be made to ensure vaccine administration during the hospitalization or at discharge.”

Vaccine Recommendations and Guidelines of the ACIP

The one possible argument that makes sense to delay a vaccine in few days or weeks before a planned surgery is that if your child has a reaction to the vaccine, even if it is a mild reaction, like a fever or irritability, then it might cause them to delay the surgery.

And you could make the same argument about delaying vaccines in the days or weeks after having surgery. Could mild reactions to a vaccine be confused with complications from the surgery?

Otherwise, your anesthesiologist’s preferences aside, a recent or upcoming surgery is not a true contraindication to getting vaccinated, especially if it is a vaccine that your child is already past due for or needs because of a local outbreak, etc.

nless they are giving these kids the oral polio vaccine or plan on them sharing a room with a bone marrow transplant patient, they don't need to worry about shedding. But that's only one of the reasons that this hospital's recommendations don't follow ACIP guidelines.
Unless they are giving these kids the oral polio vaccine or plan on them sharing a room with a bone marrow transplant patient, they don’t need to worry about shedding. But that’s only one of the reasons that this hospital’s recommendations don’t follow ACIP guidelines.

What happens if you delay getting your child vaccinated because of a planned surgery and they get exposed to someone with measles or chicken pox?

Fortunately, this isn’t usually an issue unless your child is already behind on their vaccines and needs to catch up. After all, there is a lot of flexibility built into the immunization schedule, so that your child could get all of their vaccines on time, even with a planned or unexpected surgery.

More on Surgery and Vaccines

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