Will Thimerosal Removal Change Your Ability to Get Vaccinated?

The Advisory Committee for Immunization Practices  (ACIP) and the U.S. Health & Human Services (HHS) Department’s decision to remove thimerosal from vaccines has caused a lot of fear. One group is people who wonder if they’ve taken something harmful. Another group wonders if it’ll affect their child’s access to needed vaccines.

The first group can hopefully put their worries to rest. The amount of himerosal you get through vaccination isn’t harmful. We have over 100 years of data to prove this. 

Whether or not this decision will affect vaccine access is a little more complex. The short answer is that it shouldn’t. The longer answer is that there’s no reason that it should, and we really hope it doesn’t. 

We talked to pediatrician Joshua Jakum, MD, about these concerns and asked what parents can do to make sure their child stays safe.

Is the Thimerosal Decision Going to Affect My Child’s Vaccines?

Currently, none of the childhood vaccines for children under the age of 6 contain thimerosal, and they haven’t for more than two decades (since 2001). Many, like the MMR and chickenpox (Varicella) vaccines, have never contained thimerosal.

The FDA Modernization Act of 1997

In 1997, experts reviewed the childhood vaccine schedule. They discovered that when infants got 3 different vaccines at the same time, the total thimerosal was higher than the recommended guidelines.  

The 3 vaccines were:

• DTaP
• Hepatitis B
• Haemophilus influenzae type b (Hib)

All 3 are now thimerosal-free.

What Led to the FDA Modernization Act?

There weren’t any reported effects that prompted the change. But for the most part, especially when thinking about kids, medical professionals tend to be extremely cautious.

Jakum agrees that the process has extreme caution built in. “It’s a key part of our system,” he says.

The childhood immunization schedule is dynamic, which means it changes as we learn more. It also goes through regular review, where doctors look at not just the individual components, but also what the total effect is.

Data is collected on an ongoing basis and reexamined regularly. Whenever there is a possible improvement, like the FDA Modernization Act, it’s made promptly.

Which Vaccines Have Thimerosal?

Some flu vaccines do, but usually only the multi-dose flu vaccines. These are usually only given to adults.

Roughly 4% of current flu vaccines have thimerosal. That means it may be harder to get a flu vaccine this season, since that 4% may be removed from use.

Adult tetanus boosters and 1 of the meningococcal vaccines for teenagers also include thimerosal. There are alternatives to both of these.

But Why Do Any Vaccines Have Thimerosal?

Medical supplies need to be stored safely, which means preventing the growth of any potentially harmful microbes. In 1928, shortly before thimerosal was available, a multi-dose vial of a diphtheria vaccine was contaminated with a staph infection. Many of the children who got this vaccine died due to the bacteria. Safe preservatives, like thimerosal, helped prevent these tragedies. 

 Starting in the 1930s, thimerosal was added to:

• Antiseptic ointments
• Medical creams and gels
• Nasal sprays
• Eye drops
• Contact lens solutions
• Vaccines

How Much Thimerosal Is in These Vaccines?

25 micrograms (represented as μg or mcg).

It’s very hard to visualize amounts this small. A speck of dust is estimated to be around 10 micrograms. It would take 1,000 micrograms to equal 1 milligram.

How Do We Know It’s Not Harmful?

Thimerosal has been in use since the 1930s. We have almost 100 years of safety data. Its addition and subtraction from vaccines hasn’t been connected to any increases in side effects.

If thimerosal were connected to conditions like autism, diagnoses would have declined after its removal. Instead, the opposite has happened.

When we eliminate a harmful substance from use, we usually see positive effects happen quickly. For example, when we stopped using leaded gasoline, there was an observable decline in some of the health problems children faced. This could be measured through blood lead levels.

There has been no such change associated with removing thimerosal.

So, Why Is It Being Banned?

Great question. We’re not sure. Jakum agrees that it’s likely due to confusion about the difference between ethylmercury and methylmercury. While these two compounds are both built on mercury, their effect in the body are very different.

Compounds built from the same building blocks aren’t the same. That’s why carbon dioxide, which we breathe out, and carbon monoxide are different. And that’s just with a single oxygen molecule difference. Similarly, despite their similar names and common ingredient, ethyl and methylmercury aren’t the same.

When methylmercury builds up in the body, it can cause serious health concerns. Usually, this is due to repeated exposure, like a diet with a lot of mercury-tainted fish.

Thimerosal contains ethylmercury. Ethylmercury is much less concerning. It breaks down in the body more quickly, which keeps it from building up. You’d have to consume a large amount at once to be negatively impacted.

Do I Need to Call My Pediatrician Now to Schedule My Child’s Remaining Vaccines?

If your child isn’t up to date on any vaccines, they definitely should be. Especially with school starting. But as of right now, they shouldn’t be impacted.

Adults looking for their flu vaccine this winter are going to have to look a little harder.

Yeah, But the Flu Vaccine Isn’t One of the Important Ones, Right?

While 2 children tragically died of measles last year, 216 children died of the flu. Most weren’t vaccinated.

In healthy children, the flu vaccine reduced the risk of death by nearly 66%.

96% of flu vaccines are made without thimerosal. If you’re really concerned about it, you can ask your provider at the time of vaccination about the specific type being used. Hopefully, manufacturers will increase production of these to account for the loss of the other options.

Talk to Your Doctor

It can be hard to know what’s true online. Take your concerns directly to your doctor. They can provide you with verified information and walk through your unique concerns and medical history.