Correcting this week’s misinformation: week of October 8, 2026

Dr. Eric Berg, DC, says people don’t realize vaccines are toxic because they are tested against other vaccines. So why aren’t they tested against saline placebos?

• Vaccine studies can use saline, another vaccine, or certain ingredients for comparison. The choice depends on the question and how to protect participants.
• An ingredient’s safety depends on its amount and how the body handles it—not just its name.
• Vaccines saved an estimated 154 million lives over 50 years. They can cause side effects, but serious reactions are rare, and vaccines prevent far more harm than they cause.

A placebo is something used in a study to help scientists compare results. Many people think a placebo must always be saline, or salt water, but that is not true.

There are several kinds of comparison groups in vaccine studies. One uses an inert placebo, such as saline, which has no active ingredients. Another uses an active control, such as a vaccine that already works. Some comparisons use certain vaccine ingredients without the part that teaches the body to recognize the germ. These different comparisons help scientists answer different questions.

Scientists choose the comparison based on what they need to learn and how to protect the people taking part. A saline placebo can be used when there is no vaccine that already works. But if a safe and effective vaccine already exists, giving some people only saline may be unethical. It could leave them unprotected from a serious disease.

Giving protection is especially important for babies and children. If scientists already know a vaccine can prevent serious illness, they do not want to leave some children unprotected just to use saline in a study.

The pneumococcal vaccine is a good example. Prevnar-13 was tested against Prevnar-7, an older vaccine that already worked. If researchers had used saline instead, some children would have been left unprotected from dangerous bacterial infections. That could have put them at risk of serious illness or death. Comparing the new vaccine with the older vaccine helped scientists assess its safety and protection while still protecting children against the bacteria covered by Prevnar-7.

Both inert placebos and active controls are accepted in science. These studies help answer two main questions: Is the vaccine safe? And does it protect people from disease? No single comparison can answer every safety question, so safety checks continue after vaccines become available.

What about the ingredients used in an active control trial? An ingredient’s name alone does not tell us whether it is harmful. For vaccine ingredients, we consider the amount, how they enter the body, and how the body handles them.

We can also look at the bigger picture: how much harm vaccines prevent compared with the harm they can cause. Between 1974 and 2024, vaccination against 14 diseases saved an estimated 154 million lives worldwide. Vaccines also prevent illnesses that can cause paralysis, brain damage, and other lasting problems.

Vaccines can cause side effects, too. Most are mild, like a sore arm or fever. Serious reactions are rare, and the risks depend on the vaccine and the person. For example, a severe allergic reaction happens after roughly 1–10 out of every million vaccine doses, depending on the vaccine.

And many vaccines have also been tested with inert placebos, including those for rubella, pneumococcal disease, Hib disease, HPV, polio, measles, Tdap, and COVID. The key is choosing a comparison that answers the question while protecting the people who take part.

Mary Talley Bowden claims that she sees patients whose lives were destroyed by mRNA vaccines every day and compares it to the problems with thalidomide during the 1960s.

• A large study of veterans linked COVID vaccination to about 38% lower risk of serious heart problems related to COVID.
• Vaccination was also linked to about 6% lower risk of major heart problems from any cause.
• Benefits were greater for older adults and people with other health conditions. The findings describe group patterns, not what will happen to each person.

These concerns deserve careful review. However, a health problem that happens after vaccination is not always caused by the vaccine. A doctor’s account alone cannot show the cause or tell us how common a problem is.

A large study of U.S. veterans found that the updated 2024–2025 COVID vaccine was linked to a lower risk of serious heart problems. People who received it had about a 38% lower risk of major heart problems linked to COVID. They also had about a 6% lower risk of major heart problems from any cause. These problems included heart attacks, strokes, and heart failure.

These findings describe patterns across a large group. They do not predict what will happen to one person. The study also found that the amount of protection was generally greater for people with other health conditions, whose starting risk was higher. Because researchers used health records rather than randomly assigning vaccines, the findings show a link but cannot fully prove cause and effect.

COVID vaccines have rare but real risks. The benefits and risks can differ based on a person’s age and health. Both deserve attention when making vaccine decisions.

During the pandemic, vaccination also helped prevent deaths and hospital stays. Researchers estimated that the U.S. vaccination program prevented about 3.2 million deaths and 18.5 million hospital stays from December 2020 through November 2022. They also estimated that it saved $1.15 trillion in medical costs. These are estimates based on a computer model, rather than exact counts.

Dr. Suzanne Humphries says that if you drop a vial of mercury on the floor, you would need to call a special group of people to clean up the hazardous spill. She says since vaccines contain mercury, they are just as hazardous.

• Thimerosal helps prevent germs from growing in some multi-dose vaccines. 
• Thimerosal contains ethylmercury, which leaves the body quickly, unlike the mercury found in some fish.
• Research supports its safety in vaccine amounts and has not found a link to autism or harm to brain development.

The safety data sheet from GlaxoSmithKline gives directions for cleaning up spilled flu vaccine. For small spills, it says to wipe up the liquid with a cloth. These directions are for workplace cleanup. They do not, by themselves, tell us whether an ingredient is safe to inject.

Thimerosal is a preservative. It helps stop bacteria and fungi from growing in vaccine bottles that hold more than one dose. Each time a needle enters the bottle, germs could get inside.

Most vaccines do not contain thimerosal. It is still used in some multi-dose vaccines, including some vaccines used in other countries. These bottles can help keep vaccination costs down and take up less space in refrigerators. Thimerosal prevents germs from growing; it does not replace the need to keep vaccines at the right temperature.

U.S. flu vaccine guidance changed in 2025. Federal recommendations now call for children and adults to receive single-dose flu vaccines without thimerosal. This change in guidance does not mean thimerosal was found to be unsafe.

Some people worry about thimerosal because it contains mercury. But different forms of mercury act differently in the body. Thimerosal breaks down into ethylmercury, which leaves the body quickly. This differs from methylmercury, found in some fish, which stays in the body longer.

Research in babies, including those born early or with low birth weight, found that the amount of ethylmercury in the blood drops by half in about three to seven days. It leaves the body mainly through stool. Blood mercury levels return to their starting level within about a month.

Research has not found a link between thimerosal in vaccines and autism or damage to brain development. Thimerosal was removed from most routine childhood vaccines in the United States by 2001 as a precaution, not because harm had been proven. Autism diagnoses continued to rise afterward.

The evidence supports the safety of thimerosal in the small amounts used in vaccines. Its name and the presence of mercury alone do not tell us how it affects the body.