Tag: side effects

Can Vaccines Cause ITP?

ITP is an abbreviation for idiopathic thrombocytopenic purpura.

It is a condition in which our platelets get destroyed, leading to excessive bruising and bleeding, since platelets are needed for normal blood clotting.

What Causes ITP?

To understand what causes ITP, it is important to know it is also often referred to as immune thrombocytopenic purpura, because it is typically the cells of our own immune system that destroys our platelets.


Well, that’s where the idiopathic part comes in.

We don’t know why people develop ITP, although classically, ITP is thought to follow a viral infection, including Epstein-Barr virus (mono), influenza, measles, mumps, rubella, and varicella (chicken pox). ITP has also been associated with many other viral infections, from Dengue fever to Zika.

“Often, the child may have had a virus or viral infection approximately three weeks before developing ITP. It is believed that the body’s immune system, when making antibodies to fight against a virus, “accidentally” also made an antibody that can stick to the platelet cells. The body recognizes any cells with antibodies as foreign cells and destroys them. Doctors think that in people who have ITP, platelets are being destroyed because they have antibodies.”

Pediatric Idiopathic Thrombocytopenia Purpura (ITP)

These children with ITP, usually under age 5 years, develop symptoms a few days to weeks after their viral infections. Fortunately, their platelet counts usually return to normal, even without treatment, within about 2 weeks to 6 months. Treatments are available if a child’s platelet count gets too low though.

Can Vaccines Cause ITP?

The measles vaccine is the only vaccine that has been clearly associated with ITP.

“The available data clearly indicate that ITP is very rare and the only vaccine for which there is a demonstrated cause-effect relationship is the measles, mumps and rubella (MMR) vaccine that can occur in 1 to 3 children every 100,000 vaccine doses.”

Cecinati on Vaccine administration and the development of immune thrombocytopenic purpura in children

Even then though, the risk of ITP after a measles containing vaccine, like MMR or ProQuad, is much less than after getting a natural measles infection, so worry about ITP is a not a good reason to skip or delay getting vaccinated.

What about other vaccines?

There is no good evidence that other vaccines, including the chicken pox vaccine, DTaP, hepatitis B vaccine, or flu vaccine, etc., cause ITP.

What about Gardasil? ITP is listed in the package insert as an adverse reaction for Gardasil, but only in the postmarketing experience section, so it does not mean that the vaccine actually caused the reaction, just that someone reported it.

Although ITP is listed in the PI for Gardasil, studies have shown that there is no association.
Although ITP is listed in the PI for Gardasil, studies have shown that there is no association.

Several large studies have actually been done that found no increased risk for ITP after getting vaccinated with Gardasil.

What to Know About Vaccines and ITP

Although measles containing vaccines can rarely cause ITP, vaccines prevent many more diseases that can cause ITP.

More on Vaccines and ITP


Myths About the Yellow Fever Vaccine

Endemic yellow fever was eliminated in the United States in 1905, way before the first yellow fever vaccine was developed (1935) and licensed (1953).

How did that work?

Yellow fever is a now vaccine preventable disease that is spread by mosquito bites.

In the United States, it was actually eliminated by controlling the Aedes aegypti mosquitoes that spread the yellow fever virus before the vaccine was even developed. These control efforts were also done in Cuba, Panama, and Ecuador, etc., places where yellow fever was common and led to outbreaks in the United States.

Why Haven’t We Eradicated Yellow Fever?

So why is yellow fever still a problem if we can control the the Aedes aegypti mosquitoes that carry the yellow fever virus?

“Mosquitoes breed in tropical rainforests, humid, and semi-humid environments, as well as around bodies of still water in and close to human habitations in urban settings. Increased contact between humans and infected mosquitoes, particularly in urban areas where people have not been vaccinated for yellow fever, can create epidemics.”

Yellow fever: Questions and Answers

It’s because we can control the mosquitoes in urban areas, in and around cities. You can’t really control or eliminate mosquitoes in tropical rain forest regions, which is why it is difficult to eradicate yellow fever, malaria, dengue fever, and other mosquito borne diseases.

But we have a vaccine, don’t we?

“Eradication of yellow fever is not feasible since we are unable to control the virus in the natural animal hosts.”

Yellow fever: Questions and Answers

Unfortunately, we aren’t the only ones who can become infected with yellow fever. Monkeys get infected with the yellow fever virus in rain forests, infect Haemagogus and Sabethes mosquitoes, which bite people in those areas.

“Urban transmission of yellow fever virus occurs when the virus is spread from human to human by the Aedes aegypti mosquitoes.”

Yellow fever – Brazil

That likely means that yellow fever will never be completely eradicated, unlike small pox.

Yellow Fever Vaccines Myths

But just because yellow fever can’t be eradicated doesn’t mean that it can’t be eliminated.

A single dose of the yellow fever vaccine is safe and provides life-long protection for 99% of people.

“Vaccination is the most powerful known measure for yellow fever prevention: a single dose can provide life-long immunity at a cost of approximately US$1.”

WHO on Eliminating Yellow Fever Epidemics (EYE) Strategy: Meeting demand for yellow fever vaccines

And as cases of yellow fever increase in some countries, like Brazil, getting more people vaccinated is the only way to stop this deadly disease.

People line up to get a yellow fever vaccine near Kinshasa.
People line up to get a yellow fever vaccine near Kinshasa. Photo by WHO/E. Soteras Jalil

Tragically, anti-vaccination myths and misinformation may be keeping folks from getting vaccinated and protected. Propaganda and anti-vaccine scare videos have them thinking that the yellow fever vaccine is dangerous, part of a conspiracy to depopulate the world, or that it doesn’t work.

It is also important to know that:

  • When traveling to or from some countries, a yellow fever vaccine isn’t enough – you need an International Certificate of Vaccination proving that you were vaccinated.

    You should not skip getting the yellow fever vaccine if you are traveling to an area where yellow fever is endemic, including many parts of areas of Africa and South America.

  • While you are most at risk during the rainy season, especially during outbreaks, it is also possible to get yellow fever during the dry season.
  • Yellow fever is a serious, life-threatening disease.
  • There is no cure for yellow fever.
  • While serious side effects to the yellow fever vaccine have been reported, including anaphylaxis, yellow fever vaccine-associated neurologic disease (YEL-AND), and yellow fever vaccine-associated viscerotropic disease (YEL-AVD), they are very rare.
  • The yellow fever vaccine is a live virus vaccine, but shedding is not an issue. Unless at a high risk of exposure, getting the yellow fever vaccine is usually not recommended if you are pregnant or breastfeeding though.
  • It is not usually necessary to get a booster dose of the yellow fever vaccine.
  • Some countries require proof of yellow fever vaccination if you have traveled from a country where there is still a risk of getting yellow fever, so that you don’t import yellow fever into their country.

As yellow fever cases are on the rise in Brazil, with an associated increase in travel associated cases, it is important that everyone understand that vaccines are safe and necessary.

What to Know About Yellow Fever Vaccine Myths

Yellow fever cases are increasing and so are anti-vaccine myths about the yellow fever vaccine, which are keeping some folks from getting vaccinated and protected, even as they are threatened by a potential outbreak.

More on Yellow Fever Vaccines Myths

Which Vaccine Is the Most Dangerous?

In 2002, Dan Rather did a report for 60 Minutes on “The Most Dangerous Vaccine.”

Can you guess which vaccine he was reporting on?

Which Vaccine Is the Most Dangerous?

You are thinking his report was about MMR, the so-called “autism shot,” right?

“And then the nurse gave my son that shot. And I remember going, “Oh, God, no!” And soon thereafter I noticed a change. The soul was gone from his eyes.”

Jenny McCarthy on Oprah

It was around the time that the “media’s MMR hoax” was in high gear.

“Whatever you think about Andrew Wakefield, the real villains of the MMR scandal are the media.”

Ben Goldacre on The MMR story that wasn’t

But 60 Minutes had already done a segment on “The MMR Vaccine” with Andrew Wakefield back in 2000.

The smallpox vaccine was considered the most dangerous as President Bush decided whether or not it was necessary to vaccinate millions against this deadly disease.
The smallpox vaccine was considered the most dangerous as President Bush decided whether or not it was necessary to vaccinate millions against this deadly disease.

No, this story was about the smallpox vaccine.

And if you had to rank vaccines from safest to most dangerous, then yes, you could say that the original smallpox vaccine, the one with the most side effects, is the most dangerous.

Fortunately, that very same smallpox vaccine helped eradicate smallpox and few of us need to even think about getting a smallpox vaccine. It is still given to some folks in the military though and is available if necessary.

The story was about a plan to vaccinate many more people, including hospital workers. At the time, there was a worry about terrorist attacks using smallpox.

“Here’s another way to do it. We can make the vaccine. Make sure we understand who’s going to get it, who’s going to be giving it. Then wait, wait for there to be one case of documented smallpox somewhere on the face of this earth and then we can move into vaccinating people, large numbers of people.”

Paul Offit, MD

Not everyone was on board with the plan though. Dr. Offit, for one, didn’t think that it was a good idea to start vaccinating people for a threat that we didn’t know would appear, especially since the older smallpox vaccine had more side effects than other, more modern vaccines.

Again, that doesn’t mean that the smallpox vaccine is dangerous.

Smallpox is dangerous and deadly. If there is a risk that you could get smallpox, then you would much rather have the smallpox vaccine, even with its side effect profile.

And fortunately, a new attenuated smallpox vaccine, Imvamune, is also available and has less side effects. Two other smallpox vaccines, ACAM2000 and APSV, which are similar to the original DryVax vaccine that was used in the US, are also still being used until Imvamune is formally approved by the FDA.

Vaccine preventable diseases are dangerous.

While they aren’t 100% without risk, vaccines, from rotavirus to HPV, are safe and necessary.

What To Know About the Most Dangerous Vaccine

All vaccines are safe and effective, but if you had to rank them, the original smallpox vaccine would be the most dangerous because it has the most side effects.

More on the Most Dangerous Vaccine


What Causes Non-Stop Crying After DTaP Vaccines?

Most children cry after getting a shot.

Fortunately, they can usually be comforted quickly.

Historically, there has been one situation where kids might cry for longer periods of times.

Non-Stop Crying After DTaP Vaccines

The DTP vaccine was known to cause non-stop crying, for 3 hours or more in up to about 1 child out of 1,000.

“Persistent crying following DTaP (as well as other vaccines) has been observed far less frequently than it was following the use of DTP. When it occurred after DTP, it was considered to be an absolute contraindication to further doses of pertussis-containing vaccine. When it occurs following DTaP, it is considered a “precaution” (or warning). If you believe the benefit of the pertussis vaccine exceeds the risk of more crying (which, although unnerving, is otherwise benign), you can administer DTaP.”

Immunization Action Coalition on Ask the Experts about DTP

Although uncommon, it is certainly scary to have a child cry for 3 hours or more after a vaccine.

I guess that’s one good reason we don’t use the DTP vaccine anymore. On the other hand, although the newer DTaP has fewer side effects, it doesn’t work as well as the older DTP vaccine at protecting kids against pertussis.

What Causes Non-Stop Crying After DTaP Vaccines?

Some people have very wrong ideas about what caused this non-stop crying after the DTP vaccine, which is reflected in the nick-names they gave it, such as the “DTP scream,” “cry-encephalitis,” or the “encephalitic cry.”

If your child has had non-stop crying after their DTP vaccine, or DTaP vaccine for that matter, you can be reassured that they didn’t have encephalitis!

The forums of Mothering.com are notorious for pushing anti-vax misinformation, including the idea of an "encephalitic cry."
The forums of Mothering.com are notorious for pushing anti-vax misinformation, including the idea of an “encephalitic cry” after DTP vaccines.

Again, although it is scary to have your child crying non-stop for 3 hours or more, this crying is benign and has no long term effects.

So what is causing it?

It is thought to be a painful local reaction.

Remember that the next time you see a vaccine scare video about the “DTaP scream” or talk about encephalitis

What to Know About DTaP Crying

Crying non-stop for 3 hours or more after a vaccine can be scary. Fortunately, DTaP crying is not caused by encephalitis or any other terrible thing you might read about. It is a painful local reaction.

More on DTaP Crying

Rash After the MMR – Is This Normal?

It is not uncommon to get a rash after your child gets their MMR vaccine.

In fact, about 1 in 20 people get a rash after their first dose of MMR.

It typically shows up about 6 to 14 days after the dose.

Fortunately, it doesn’t mean that your child has full-blown measles as some people suspect.

Rash After the MMR

So why do some kids get a rash after their MMR?

It depends on which rash they have.

While there is one classic MMR rash that we think about, there are actually a few other rashes that can occur even more rarely, including:

  • hives – an allergic reaction to the vaccine or one of it’s components
  • petechia and/or purpura – caused by temporary thrombocytopenia (low platelet count) in about one out of every 30,000 to 40,000 doses of vaccine given

And then there is the rash that up to 5% or people get about 7 to 10 days after their dose of MMR – a mild vaccine reaction that goes away on its own without treatment.

Most importantly, the presence of this measles-like rash does not mean that your child has actually gotten measles from the vaccine.

How do we know?

For one thing, the MMR vaccine is made with an attenuated or weakened form of the measles virus, so it can’t actually cause full-blown measles, unless maybe a child has a severe immune system problem.

Also, there is no viremia after vaccination.

“There are no reports of isolation of vaccine virus from blood in normal humans.”

Plotkin’s Vaccines

It is also important to note that “person-to-person transmission of vaccine virus has never been documented.”

And kids who get a rash after their MMR vaccine are not considered to be contagious. At most, you would expect them to shed the weakened vaccine virus, but they don’t.

What’s causing this measles-like rash then?

Like the fever, it is thought to be a delayed immune response to the live, attenuated virus in the vaccine.

When the Rash Really is Measles

Are there any situations in which a child gets a rash after their MMR vaccine and it could really be measles?


An infant hospitalized during a measles outbreak in the Philippines in which 110 people died.
An infant with wild type measles hospitalized during a measles outbreak in the Philippines in which 110 people died. Photo by Jim Goodson, M.P.H.

Your child could have been exposed to wild type measles right around the time they got vaccinated, and then went on to develop regular measles.

While getting a measles vaccine within 72 hours of exposure (post-exposure prophylaxis) can reduce your chance of getting measles, it isn’t a perfect strategy.

Or your child could have been vaccinated and been one of the few people for whom the vaccine failed to work. So their rash, again, would be from a wild type strain of measles that they were exposed to and not from the shot.

Can you tell the difference if someone has measles from the vaccine or from a wild type strain?


“During outbreaks, measles vaccine is administered to help control the outbreak, and in these situations, vaccine reactions may be mistakenly classified as measles cases.”

CDC on Genetic Analysis of Measles Viruses

You just have to test the measles strain to see if it is the wild type virus or a vaccine strain.

Does It Matter If It Is the MMR Vaccine or Measles?

About now, you are probably wondering why it matters knowing if a child’s rash is caused by measles or the MMR vaccine, right?

For one thing, if a parent thinks a vaccine gave their child measles, then they might not want to get vaccinated again. They will especially think twice about getting another MMR.

Also, if a child really does have full-blown, wild type measles and you simply blame their MMR vaccine, then you might miss someone else in the community that exposed the child to measles. And that’s why some outbreaks are hard to stop.

Lastly, if you simply blame the vaccine, you might miss something else that is causing the child to be sick.

Need an example?

During the 2010 measles outbreaks in Canada, a 15-month-old develop a rash, fever, and other symptoms 12 days after getting their MMR vaccine. Did the have measles, a vaccine reaction, or something else?

Turns out that he had scarlet fever.

The child tested positive for Streptococcus pyogenes (group A streptococcus), the bacteria that causes strep throat and scarlet fever. He also tested positive for vaccine strain measles. He did not have the wild strain of measles, and in fact, did not have measles at all.

Again, he had scarlet fever and it was just a coincidence that he had recently received an MMR vaccine.

But isn’t there another case report from Canada that does prove that you can get full-blown measles from the MMR vaccine? While there is such a case report, it is hardly proof of anything.

“It is possible that the case’s symptoms were not measles-vaccine-related but an inter-current illness confounding the presentation.”

Murti et al on Case of vaccine-associated measles five weeks post-immunisation, British Columbia, Canada, October 2013

The problem with the case?

For one thing, the child already had high levels of IgG antibodies at the time he had the rash, which developed 37 days after he got his vaccine.

“The two-fold rise between acute and convalescent measles-specific IgG suggests the vaccine-mediated immune response had been underway prior to the onset of symptoms.”

Murti et al on Case of vaccine-associated measles five weeks post-immunisation, British Columbia, Canada, October 2013

This was neither a typical reaction nor a typical case. And it very well might not have been measles. If it was, it was a very rare exception to the rule that rashes after the MMR vaccine aren’t full-blown measles.

What to Know About Rashes After the MMR Vaccine

The rash that your child can get after their MMR vaccine is not a sign that they have developed full-blown measles, instead, it is a mild vaccine reaction that will quickly go away without any treatment.

More on Rashes After the MMR Vaccine


What Are the Benefits of the Flu Shot?

So that flu shot you got isn’t going to be 100% effective this year…

That doesn’t mean that you didn’t make a great decision getting your family vaccinated and protected! Or that you shouldn’t still take the time to go out and get a flu shot if you haven’t yet.

The flu vaccine works, even if it isn’t perfect.

Benefits of the Flu Shot

The benefits of the flu shot go far beyond just avoiding the flu.
The benefits of the flu shot go far beyond simply helping you avoid the flu. Most flu related deaths in children are in those who are unvaccinated.

What good is the flu shot if it doesn’t completely eliminate your risk of catching the flu?

How about the simple fact that even if doesn’t completely eliminate that risk 100%, a flu shot does decrease your risk of getting sick with the flu?

But it doesn’t end there.

Other benefits of a yearly flu shot include that it can:

  • reduce the risk of flu-associated death in children with underlying high-risk medical conditions by just over half (51%)
  • reduce the risk of flu-associated death in healthy children by just over two thirds (65%) – this is important, because despite what most people believe, many of the kids who die with the flu each year don’t have any underlying health problems
  • reduce how sick you get, even if you do get the flu, reducing “deaths, intensive care unit (ICU) admissions, ICU length of stay, and overall duration of hospitalization among hospitalized flu patients.”
  • reduce the risk of the babies getting hospitalized in their first 6 months when pregnant moms got a flu shot
  • reduce asthma attacks leading to emergency visits and/or hospitalizations in people with asthma

Getting vaccinated can also reduce the risk that you get sick with the flu and get someone else sick.

Considering all of these benefits, it is hard to imagine why anyone wouldn’t get a flu shot, even in year’s when it might just be 60% or even 40% effective.

I mean, it isn’t like the flu shot is actually going to give you the flu or anything…

Have you gotten your flu shot yet this flu season?

What to Know About the Benefits of the Flu Shot

In addition to helping you avoid getting sick with the flu, getting a yearly flu shot has many other indirect benefits, so that even if you get the flu, it can help you avoid getting really sick and ending up in the hospital, ICU, or getting so sick that you don’t survive.

More on the Benefits of the Flu Shot

Updated February 17, 2018

What Are Hypotonic-Hyporesponsive Episodes?

Just about any side effect after a vaccine can be scary for parents.

What if your child suddenly became limp, wasn’t responsive, and was pale?

That would be scary for any parent.

What Are Hypotonic-Hyporesponsive Episodes?

But that’s just what can happen when a child has a hypotonic–hyporesponsive episode (HHE).

“A hypotonic-hyporesponsive episode (HHE) is the sudden onset of hypotonia, hyporesponsiveness, and pallor or cyanosis that occurs within 48 hours after childhood immunizations.”

DuVernoy et al on Hypotonic-hyporesponsive episodes reported to the Vaccine Adverse Event Reporting System (VAERS), 1996-1998

These types of episodes were once thought to happen once for every 1,750 DTP vaccines given.

HHE is much more rare since we switched to a new pertussis vaccine.
HHE is much rarer since we switched to a new pertussis vaccine.

Fortunately, although they certainly do sound scary, the episodes stop on their own and  don’t cause any permanent harm.

Hypotonic-hyporesponsive episodes were even removed as table injuries after DTP back in 1995. It is not that HHE can’t occur after DTP, DTaP, or other vaccines, but rather that HHE doesn’t then cause any permanent neurological damage to the child.

And it is rare for kids to have a second episode, so they can continue to get vaccinated. HHE is not a good reason to skip or delay all of your child’s vaccines. While not a contraindication to getting vaccinated, having an episode of HHE “within 48 hours after receiving a previous dose of DTP/DTaP,” is listed as a precaution to getting another dose of DTaP or Tdap though.

“In general, vaccinations should be deferred when a precaution is present. However, a vaccination might be indicated in the presence of a precaution if the benefit of protection from the vaccine outweighs the risk for an adverse reaction.”

CDC on Vaccine Contraindications and Precautions

Also, HHE has become even more rare since we switched to using DTaP, instead of the older DTP vaccine. So being worried about HHE is definitely not a good reason to skip or delay any vaccines.

What to Know About Hypotonic-Hyporesponsive Episodes

Hypotonic-hyporesponsive episodes were more common after the older DTP vaccines, but still didn’t cause any long term problems and aren’t a good reason to skip or delay your child’s vaccines.

More About Hypotonic-Hyporesponsive Episodes