Tag: pregnant

If It’s Vaccines, Then Why Are There Autistic Kids Who Are Unvaccinated?

Although we know that vaccines aren’t associated with autism, anti-vaccine folks can’t let go of the idea.

Paul Thomas misses the one thing his data is telling him...
Paul Thomas misses the one thing his data is telling him…

So how do they explain all of the autistic kids who are unvaccinated?

If It’s Vaccines, Then Why Are There Autistic Kids Who Are Unvaccinated?

Of course, anti-vaccine folks have a ready answer – it’s vaccines, but it’s not just vaccines.

I guess that’s how they explain the fact that there are so many autistic adults too! Well, actually no. Most anti-vaccine folks are surprised when you point out that there are so many autistic adults, as it doesn’t fit in with their idea that autism is new and caused by kids getting more vaccines than they used to.

Well, I guess mostly caused by giving so many more vaccines than we used to – there are also the autistic kids who were never vaccinated.

How do they explain those kids having autism?

Like their competing theories about how vaccines are associated with autism (it’s the MMR vaccine, no it’s thimerosal, no it’s glyphosate contaminating vaccines, etc.), they have a lot of ideas about how everything else causes autism. From fluoride and chlorine to acetaminophen and aluminum-lined containers, plus mercury, arsenic, aspartame, MSG, and the vaccines your child’s great-grandmother received – they think that just about anything and everything can cause autism. Or at least anything that they think they can sell you a treatment for, such as their supplements, special diet plans, or other “cures.”

Makes you wonder why they still focus on vaccines…

But they do, even as more studies have shown that vaccines are not associated with autism. And since vaccines don’t cause autism, it shouldn’t be surprising that there are unvaccinated children with autism. The only reason there aren’t more is that most parents vaccinate their children, so, of course, most autistic children are going to be vaccinated.

Another reason is that some parents stop vaccinating their kids once they have an autistic child. But since vaccines aren’t associated with autism, which is highly genetic and inheritable, younger unvaccinated siblings born after older siblings were diagnosed often still develop autism.

Now if vaccines didn’t cause autism in these unvaccinated kids, why would anyone still think that they caused autism in their older siblings?

“I must admit that it was through conversations with a coworker that I began to suspect something might be wrong with my youngest son. It concerned me so much that I started looking for information online. I read some of the stories and they sounded similar to what I was experiencing with my son – with the symptoms, the regression and the age at which it all started to become apparent.”

Lara’s Story: Growing Up Anti-Vaccine

Unlike some other stories you might read online, Lara’s story is about her unvaccinated autistic child.

She isn’t alone. You only have to look at personal stories and posts in parenting forums to see that there are many cases of autism among unvaccinated and partially vaccinated children:

  • “It is highly likely my 4-year-old son is autistic. And he is completely 100 percent vaccine-free. And I am just at a total loss.”
  • “I have unvaxxed kids on the spectrum, and my friend does as well.”
  • “A good friend’s son is autistic. He is totally non-vaxxed.”
  • “I seriously delayed vaccinating my son, so had very few vaxxes at the time he was diagnosed”
  • “We have autism in our unvaxxed children”
  • “I know two little boys who are both autistic, completely non-vaxxed”
  • “I have two unvaccinated children who are on the autism spectrum and have never vaccinated any of my children.”
  • “I am not sure what caused my son’s autism, but autistic he is. He is completely unvaxxed as we stopped vaxxing 10 years ago.”
  • “I have a 10 year old daughter with autism spectrum disorder… My daughter has never had a vaccine, a decision I made shortly after she was born, after much research.”

Unfortunately, while realizing that unvaccinated children can develop autism does help some parents move away from anti-vaccine myths and conspiracy theories, others get pushed deeper into the idea that it is just about toxins. It is not uncommon for some of these parents to blame vaccines they got while pregnant or even before they became pregnant, Rhogam shots, or mercury fillings in their teeth, etc.

Fortunately, most don’t though.

Take Juniper Russo, for example.

She “was afraid of autism, of chemicals, of pharmaceutical companies, of pills, of needles” when she had her baby. She just knew that vaccines caused autism when she first visited her pediatrician after her baby was born and knew all of the anti-vaccine talking points. She also later began to realize that her completely unvaccinated daughter had significant developmental delays. Instead of continuing to believe that vaccines cause autism, Ms. Russo understood that she “could no longer deny three things: she was developmentally different, she needed to be vaccinated, and vaccines had nothing to do with her differences.”

And she understands that her autistic child isn’t damaged, as hard as folks in the anti-vaccine movement still try to push the idea that she is.

More on Autistic Kids Who Are Unvaccinated

Did the FDA Admit That the Government Is Recommending Untested, Unlicensed Vaccines for Pregnant Women?

Have you heard?

There is a new bombshell from anti-vaccine folks!

It turns out, they say, that the FDA has admitted that the government is recommending untested, unlicensed vaccines for pregnant women.

Is that true?

Did the FDA Admit That the Government Is Recommending Untested, Unlicensed Vaccines for Pregnant Women?

Of course not!

Their evidence?

A response to a Freedom of Information Act request for vaccines that don’t exist. That’s right, neither Tdap nor flu vaccines are currently FDA approved for use by pregnant women.

Of course, that doesn’t mean that Tdap and flu vaccines aren’t recommended for use by pregnant women.

Wait, why the difference?

Why are pregnant women being given a vaccine that isn’t formally FDA approved for their use?

Well, vaccine manufacturers have to seek FDA approval for their products. The FDA doesn’t just up and approve new products or give them new indications. And none have ever sought approval in pregnancy.

But that doesn’t keep health experts from making off-label recommendations, such as getting a flu vaccine when you are pregnant.

“In prelicensure evaluations, the safety of administering a booster dose of Tdap to pregnant women was not studied. Because information on use of Tdap in pregnant women was lacking, both manufacturers of Tdap established pregnancy registries to collect information and pregnancy outcomes from pregnant women vaccinated with Tdap. Data on the safety of administering Tdap to pregnant women are now available.”

Updated Recommendations for Use of Tetanus Toxoid, Reduced Diphtheria Toxoid and Acellular Pertussis Vaccine (Tdap) in Pregnant Women and Persons Who Have or Anticipate Having Close Contact with an Infant Aged <12 Months — Advisory Committee on Immunization Practices (ACIP), 2011

As important as FDA approval is a recommendation from the Advisory Committee on Immunization Practices (ACIP). In fact, even after a vaccine gets approved by the FDA, it still has to get a recommendation from the ACIP before it gets on the immunization schedule and is used routinely!

“Flu shots have been given to millions of pregnant women over many years with a good safety record. There is a large body of scientific studies that supports the safety of flu vaccine in pregnant women and their babies.”

Flu Vaccine Safety and Pregnancy

Getting a flu vaccine during pregnancy is a recommendation that has been evolving since 1983. It was known to be safe then, and we are even more confident that it is safe now.

A Tdap shot has been recommended since 2011, although it was first suggested in 2008 that pregnancy was not a contraindication for receiving Tdap.

How do we know these vaccines are safe during pregnancy?

The Vaccine Safety Datalink has published more than 14 studies “related to pregnancy and vaccination during pregnancy” and has used “data to study the health of children born to women who were vaccinated during pregnancy.”

Despite what Robert F. Kennedy, Jr and his ironically named Children’s Health Defense organization might think, Tdap and flu shots in pregnancy have been well studied and have been found to be safe.

Ignoring all of the above studies, Kennedy highlights a few that he thinks found problems with flu shots in pregnancy, including one that showed “a suggestion of increased ASD risk among children whose mothers received an influenza vaccination in their first trimester,” a suggestion that was not statistically significant and which was not found in the other trimesters. And another that found an increased risk of spontaneous abortion in women who had also received a flu shot in the previous season, a safety signal that has never been seen before and which continues to be investigated.

Not surprisingly, his latest bombshell is landing with as big of a thud as his HHS lawsuit, as have most of his statements these days…

“CHD’s Chairman Robert F. Kennedy, Jr. notes that most flu shots given to pregnant women still contain a mercury-based preservative thimerosal.”

FDA Admits That Government Is Recommending Untested, Unlicensed Vaccines for Pregnant Women

Has Kennedy missed the fact that 80% of flu vaccines are now thimerosal free? It makes you wonder how he defines the word “most?”

“Thimerosal is acknowledged by Proposition 65 in California as a reproductive toxicant and exposure during pregnancy can cause learning and behavioral problems. Tdap contains aluminum, which FDA regulates as a toxin in parenteral nutrition but not in vaccines.”

FDA Admits That Government Is Recommending Untested, Unlicensed Vaccines for Pregnant Women

And what is he concerned about in thimerosal-free flu shots which also don’t contain aluminum? Are those okay in his book?

Mostly, after several flu seasons in which so many people have died, you have to wonder what his goal is here. Does Robert F. Kennedy, Jr. expect folks to skip getting a flu shot when they are pregnant and instead risk getting the flu? Should they skip their Tdap shot and risk their baby dying of whooping cough?

Or should they just stop listening to this type of anti-vaccine propaganda?

More on Did The FDA Admit That The Government Is Recommending Untested, Unlicensed Vaccines For Pregnant Women?

How Does a Mother’s Flu Shot Protect a Newborn Baby?

We know that pregnant women are supposed to get a flu vaccine.

Although recommendations on exactly when to get it have changed over the years, it has been a universal recommendation since at least the 1994-95 flu season.

But why?

How Does a Mother’s Flu Shot Protect a Newborn Baby?

One obvious way that a flu shot provides protection during pregnancy is that it reduces your risk of getting the flu while you are pregnant.

A flu shot during your pregnancy protects both you and your baby.
A flu shot during your pregnancy protects both you and your baby.

That’s good, as having the flu while you are pregnant can lead to preterm labor, a premature birth, birth defects, or a miscarriage. And of course, the flu can be life-threatening for pregnant women.

Getting a flu shot while you are pregnant can also help to make sure that you don’t get the flu after your baby is born, which not only keeps you healthy, but decreases the chance that your baby will be exposed to the flu. After all, if you get the flu, no matter how much you try to cover your cough and wash your hands, there is a good chance that you will give it to your baby.

And since babies can’t get flu shots of their own until they are at least six months old, a flu shot during pregnancy helps to make sure that your baby gets some of antibodies to protect them from the flu.

“When you get a flu shot, your body makes antibodies that also pass to your fetus. This means your baby has protection against the flu after birth. This is important because infants less than 6 months of age are too young to get the flu shot.”

Frequently Asked Questions for Patients Concerning Influenza (Flu) Vaccination During Pregnancy

Do you have to wait until late in your pregnancy to make sure that the most antibodies get passed to your baby?

While that might seem like a good idea, especially since that’s what we do for the Tdap vaccine and protection against pertussis, there are several reasons that we don’t do that with the flu vaccine, including that:

  1. pregnant mothers need the protection before flu season hits, so waiting would not be safe and could mean that you get sick with the flu before getting your shot
  2. protection from the flu vaccine shouldn’t wane or wear off so quickly that you need to get it later, after all, the earliest that you can get vaccinated is when flu vaccines first become available in August or September and that should provide good protection past the peak of flu season

When you get your flu shot while pregnant is going to have more to do with when you got pregnant in relation to the start of flu season more than anything else.

“The flu shot can be safely given during any trimester. Pregnant women can get the flu shot at any point during the flu season (typically October through May). Pregnant women should get the shot as soon as possible when it becomes available. If you are pregnant, talk with your obstetrician–gynecologist (ob-gyn) or other health care provider about getting the flu shot.”

Frequently Asked Questions for Patients Concerning Influenza (Flu) Vaccination During Pregnancy

Most importantly, remember that flu shots are considered an “essential component of prenatal care.”

While everyone should get a flu vaccine each year, since pregnant women are in a high risk group for flu complications, you should especially make sure that you get vaccinated and protected if you are pregnant. Everyone around you should get vaccinated too!

More on Flu Shot Protection During Pregnancy

Vaccine Testing and Development Timeline and Myths

New vaccines must go through a long journey before they are finally approved by the FDA and get added to the recommended immunization schedule.

vaccine-dev-testing

Vaccine Testing and Development Myths

There are many myths and much misinformation surrounding vaccine testing and development that is used to scare parents away from vaccinating their kids.

Have you heard that vaccines aren’t tested together?

Or that flu vaccines or Tdap were never tested on pregnant women?

Then there are the myths about fast-tracking, and that important steps are skipped when a vaccine is on fast track for FDA approval, or that the whole vaccine testing and development process happens very quickly.

Vaccine Testing and Development Timeline

The vaccine development process is anything but quick.

“Vaccine development is a long, complex process, often lasting 10-15 years and involving a combination of public and private involvement.”

The History of Vaccines on Vaccine Development, Testing, and Regulation

During this time of the exploratory and pre-clinical stage research and then phase 1,2, and 3 trails, vaccines are:

  • tested on animals
  • tested on small groups of people
  • tested on larger groups of people
  • tested alone
  • tested together with other vaccines
  • tested for safety
  • tested for efficacy (to make sure they work)

This often includes double-blind, placebo controlled vaccine trials.

Fast tracking does speed the process up, but not because any of the testing is skipped. The researchers just get more frequent meetings and communication with the FDA and “Eligibility for Accelerated Approval and Priority Review, if relevant criteria are met.”

“Vaccine development is a complex multidisciplinary activity, combining understanding of host-pathogen interactions at the molecular level, with clinical science, population-level epidemiology and the biomechanical requirements of production.”

Anthony L. Cunningham, et al on Vaccine development: From concept to early clinical testing

Testing doesn’t stop once a vaccine is approved by the FDA and is added to the immunization schedule either. We often continue to see testing for vaccine safety and efficacy using phase 4 trials and with our post-licensure vaccine safety system, including VAERS and the Vaccine Safety Datalink.

And of course testing continues long after we begin using vaccines to see how long their protection will last. For example, because of continued testing, we now know that Gardasil and Cervarix are providing protection that lasts at least 8 and 9 years.

What To Know About Vaccine Testing and Development

From pre-clinical studies and years of phase 1, 2, and 3 trials to continued monitoring after a vaccine is approved and added to the immunization schedule, the vaccine testing and development process helps make sure that vaccines are safe and that they work.

More About Vaccine Testing and Development

Obstetric Tetanus Is Still a Thing in the United States

Yes, even though we have had a tetanus vaccine for over 80 years, obstetric tetanus is still a thing in the United States.

Obstetric Tetanus in Kentucky

According to a report from the CDC, in July 2016, an unvaccinated Amish woman in Kentucky developed “facial numbness and neck pain, which progressed over 24 hours to stiff neck and jaw and difficulty swallowing and breathing” about nine days after “she delivered a child at home, assisted by an unlicensed community childbirth assistant.”

She  was hospitalized for a month, during which time she had seizures and was on a mechanical ventilator to help her breath for a “prolonged” amount of time.

Fortunately, her baby didn’t also develop tetanus, even though the family refused a recommended dose of tetanus immunoglobulin that could prevent neonatal tetanus from developing.

Surprisingly, after this incident, only 12% of community members agreed to be vaccinated with a tetanus vaccine. One pregnant woman even refused to get vaccinated. This is even less than the response to the Ohio measles outbreak in 2014, when up to 28% of unvaccinated Amish members got vaccinated with an MMR vaccine.

Neonatal Tetanus

An 8-day old baby with neonatal tetanus born to an unvaccinated mother.
An 8-day old baby with neonatal tetanus born to an unvaccinated mother. (CC BY 3.0)

In addition to obstetric tetanus, getting tetanus during or right after a pregnancy, neonatal tetanus is a big concern for unvaccinated mothers. Just like if their mothers don’t get a flu or pertussis containing vaccine, without a tetanus vaccine, newborn babies don’t get any passive immunity and protection against tetanus.

In 2015, 34,019 newborns died from neonatal tetanus worldwide. Amazingly, that is down from 787,000 newborns in 1988 “through immunization of children, mothers, other women of reproductive age (WRA) and promotion of more hygienic deliveries and cord care practices.”

It is not all about hygiene though. Tetanus spores are everywhere. For example, in the Kentucky case, the CDC found no evidence of “birth trauma, unsterile conditions, or other complications.”

In Montana, the baby of an unvaccinated mother developed tetanus that was linked to a non-sterile clay that was given to them by a midwife for home umbilical cord care.

Fortunately, these kinds of cases are rare. There have probably been less than 40 cases of neonatal tetanus since the early 1970s, and only two since 1989, but they should still be a reminder of what could happen if we stop getting vaccinated.

Risky Umbilical Cord Practices

Adding to the risk of getting tetanus, the same moms who aren’t getting vaccinated and protected may be following unsafe umbilical cord care practices.

“…tetanus in neonates can result from umbilical cord colonization, particularly in countries with limited resources. This infection results from contamination of the umbilical separation site by Clostridium tetani acquired from a nonsterile device used to separate the umbilical cord during the peripartum period or from application of unhygienic substances to the cord stump.”

AAP – Umbilical Cord Care in the Newborn Infant – 2016

In countries that are still combating neonatal tetanus, we hear of mothers in rural areas  putting herbs, herbal pastes, chalk, powders, clay, oils, and even butter on their baby’s umbilical cord.

These natural substances are certainly not safer than more standard care, as they can be contaminated with something else that is natural – tetanus spores.

What natural things, and risky, things can you see recommended for umbilical cord care in developed countries? How about honey, goldenseal powder, Frankincense and myrrh oil, and Aztec Healing Clay?

You don’t feed honey to infants because of the risk of botulism spores, but you are supposed to put it directly on their umbilical stump?

Some midwifes even recommend ground rosemary or other dried herbs that you are actually supposed to sprinkle directly on your baby’s umbilical stump. The use of dried herbs is especially problematic. It is well known that these products are not sterile.

“Spore forming bacteria (B. cereus, C. perfringens) that are capable of causing foodborne disease when ingested in large numbers are frequently found in spices and herbs, but usually at low levels.”

Food Microbiology. Volume 26, Issue 1, February 2009, Pages 39–43

If dried herbs are also contaminated with tetanus spores (C. tetani), and you place them on an umbilical cord stump of a child whose mother wasn’t vaccinated against tetanus, then you unnecessarily increase the risk for neonatal tetanus.

Not that you would ever hear about this risk from anyone who pushes these practices or tells these moms to avoid getting vaccinated. What happened to informed consent?

And what happens as Andrew Wakefield‘s kids continue to grow up, move beyond getting measles, and begin to have kids? If they still aren’t vaccinated, they and their babies will be at risk for diseases that we thought we had gotten well controlled, like obstetric tetanus, neonatal tetanus, and congenital rubella syndrome.

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Passive Immunity

In contrast to active immunity, like when you get a vaccine, passive immunity isn’t triggered by your own immune system.

Instead, passive immunity is the protection you can get from “someone” else.

Passive Immunity is Temporary

While the best example of passive immunity is the protection that newborn babies get from their mothers, other examples include:

  • antitoxin serum – often produced in animals, this type of serum can provide antibodies against botulism and diphtheria toxins. Examples include TAT, DAT, and HBAT.
  • immune globulin – either pooled or from a single person with high titers of antibodies, immune globulin is made from donated plasma can provide antibodies against the hepatitis A or B virus, measles, rabies, tetanus, and varicella. They can be used for postexposure prophylaxis, after you have been exposed to one of these diseases and are not already immune. Examples include IGIV, HBIG, VariZIG, RIG, and Baby BIG, etc.
  • palivizumab (Synagis) – a monoclonal antibody that is specific for the RSV product and which is given to high risk premature babies to keep them from getting sick during RSV season.

Again though, the best example of passive immunity is the transfer of a mother’s antibodies to her baby through her placenta, which can include antibodies against measles, pertussis, and hepatitis B, etc., as long as the mother has immunity to these diseases.

Of course, this type of passive immunity doesn’t mean that your baby doesn’t need to get vaccinated, a common argument of those who skip or delay getting their infants vaccinated.

The biggest problem with passive immunity is that it is only temporary. In the case of maternal antibodies, they start to wane after a few months in many cases, even though they might provide protection against many diseases for up to six to twelve months.

Polio and Passive Immunity

Passive immunity likely helped prevent young children from getting more serious cases of polio in the pre-epidemic era. While infants likely got exposed to polio when they were 6 to 12 months old, since they still had partial protection from maternal antibodies, they may have gotten diarrhea (enteric infection), but it wouldn’t progress to the more serious paralytic polio.

With better hygiene and sanitation, eventually fewer young infants got exposed to polio, and we lost this method of getting “active immunity under the cover of passive protection.” Instead, they got exposed when they were older and had lost any protection from passive immunity. This led to the epidemics of polio and paralytic polio with which we are all familiar.

Breast Milk

Breast milk is another source of passive immunity. This comes from a different type of antibody though, in addition to other substances in breastmilk. While the antibodies babies get through the placenta are IgG antibodies and are directed against most vaccine-preventable diseases, breastmilk antibodies are IgA.

IgA is also called the secretory immunoglobulin, as it is found in our saliva, and respiratory tract and intestinal secretions, but don’t enter our bloodstream. While the secretory IgA antibodies children get in breastmilk won’t protect them against most vaccine-preventable diseases, they can protect them from other viruses and bacteria that cause diarrhea and respiratory infections, etc.

For More Information On Passive Immunity:

 

References On Passive Immunity:
Vaccines (Sixth Edition), 2013

 

 

Thimerosal in Vaccines

Although it was never actually linked to any real side effects, thimerosal (mercury) was removed from almost all childhood vaccines in 1999.

Thimerosal, a preservative, only remained in flu vaccines for a few years, but thimerosal free flu vaccines have been available since 2003.

That’s also the year that the remaining non-flu vaccines with thimerosal expired – January 2003.

And this year, at least “120 million doses of thimerosal-free or preservative-free influenza vaccine will be produced.” That means that over 75% of flu shots are thimerosal free, leaving only some multi-dose vials of flu shots to still have thimerosal, but making it easy to avoid if you want to.

Myth of Continued Exposure to Mercury in Vaccines

Although thimerosal was removed from vaccines in 1999, some anti-vax folks still claim that many vaccines contain mercury.
Although thimerosal was removed from vaccines in 1999, some anti-vax folks still claim that many vaccines contain mercury. Photo courtesy of Refutations to Anti-Vaccine Memes

Although most anti-vaccine groups have moved on to other conspiracy theories to scare parents, some still falsely claim that vaccines continue to be made with thimerosal and that thimerosal is dangerous.

Robert F. Kennedy Jr., for example, continues to claim that even though thimerosal has been removed from pediatric vaccines, “thimerosal levels remain virtually unchanged.” This is mostly, he claims, because of flu shots with thimerosal. Also, when a pregnant woman gets a flu shot, Kennedy claims that the fetus gets a bolus of thimerosal “that’s about 800 times the amount of mercury the CDC recommends.”

First, it is important to remember that the original concerns about thimerosal were because children who received a complete set of thimerosal containing vaccines (only hepatitis B, DTaP, and Hib ever had thimerosal) could get up to 187.5 micrograms of ethyl mercury by the time they were six months old, which exceeded the EPA limits for methyl mercury ingestion (but was less than the FDA limits). They aren’t the same type of mercury though, and thimerosal free versions of DTaP and Hib were already available in the late 1990s, so many kids likely got less than 187.5 micrograms of ethyl mercury.

Since thimerosal was removed from almost all vaccines beginning in 1999, that left flu vaccines as the main pediatric vaccine that still used thimerosal as a preservative. So did expanded flu shot recommendations for kids mean that they still got a lot of thimerosal over the years?

It is extremely unlikely that many kids have gotten each and every one of their yearly flu vaccines with thimerosal. It is more likely that they got just a few with thimerosal and the rest without, as thimerosal free flu vaccines became more widely available. After all, a flu vaccine with reduced thimerosal was available as early as 2002.

In 2003, thimerosal free flu shots became available and Flumist, a thimerosal free flu nasal spray vaccine was also approved. The supply of thimerosal free flu vaccines increased each and every year. For the 2014-15 flu season, over 100 million doses of flu vaccine are available that are thimerosal free or preservative free (with only trace amounts of thimerosal).

Even if kids did get flu vaccines with thimerosal each year though, would it matter? A 2008 study in Pediatrics, “Mercury Levels in Newborns and Infants After Receipt of Thimerosal-Containing Vaccines,” found that the half-life of ethyl mercury was about two days, “suggesting that exposure to thimerosal-containing vaccines does not result in an accumulation of mercury in blood.” And the highest blood level they found was less than 5-8 nanograms/ml, which is far less than the 187.5 micrograms that anti-vax groups continue to talk about, even in infants who had already received a cumulative dose of 162.5 micrograms of thimerosal.

What about flu shots in pregnancy?

A 2010 study in Pediatrics, “Prenatal and Infant Exposure to Thimerosal From Vaccines and Immunoglobulins and Risk of Autism,” found that “prenatal and early-life exposure to ethylmercury from thimerosal-containing vaccines and immunoglobulin preparations was not related to increased risk of” autism spectrum disorders. Two other studies have also found that prenatal exposure to thimerosal from immunoglobulin preparations, like Rho(D) immune globulin, during pregnancy were not associated with an increased risk for autism.

And also consider that fewer than 15 to 30% of pregnant women got flu shots before 2009. After 2009 and the H1N1 pandemic, rates did increase, but only to about 38 to 52%.

Although current recommendations don’t state a preference for the type of flu shot for pregnant women, it is likely that at least some of them got thimerosal free flu shots. In California, for example, since the passage of their Mercury Free Act in 2006, pregnant women and children younger than age 3 years have to get vaccines that are ‘mercury free.’

What To Know About Thimerosal in Vaccines

Thimerosal is a preservative that was removed from vaccines beginning in 1999, which means that most teens today got little or no exposure to thimerosal from vaccines.

More Information About Thimerosal in Vaccines:

Updated April 8, 2017