Lyme disease controversies, explained simply

Before you read

Lyme disease is not simple. Doctors, scientists, patients and governments have argued about it for more than 40 years, and they still do.

If you are dealing with it, whether you just pulled off a tick or have been sick for years, you may already know it can stay with you for a long time. It can touch your health, your work, your family and how much you trust the people who are supposed to help.

The people behind Beat Lyme were deeply moved by Kris Newby’s book Bitten: The Secret History of Lyme Disease and Biological Weapons (2019). It made us realize that the story of Lyme disease might not be an entirely natural one. Newby’s reporting raised questions about Cold War research on ticks that we could not stop thinking about, and in December 2025 Congress ordered an official review of that research. Many scientists disagree that military research played any role, and we explain why below. Either way, the book made us want to look honestly at every side of the Lyme story, including the uncomfortable parts.

This page does not tell you what to believe. For each debate, we explain what each side says and what has actually been documented, with links to the sources. Then it is up to you to judge and make up your own mind.

The ten big debates

1. Where did Lyme disease come from?
2. Do the standard tests work?
3. Is “chronic Lyme” real?
4. How long should antibiotics last?
5. Why do doctors’ groups disagree?
6. What happened to the first vaccine?
7. How common is Lyme, and can it be missed?
8. Co-infections, mold and other conditions
9. Are we doing enough to prevent Lyme?
10. Are ticks only a problem in the Northeast?

1. Where did Lyme disease come from?

In short: Some people believe Lyme disease is linked to Cold War weapons research on ticks. Scientists say the bacteria are far older than any lab. Congress has now ordered an official review of that research.

What some people believe

Plum Island sits off the eastern tip of Long Island, across the water from Lyme, Connecticut, where a 1975 cluster of cases gave the disease its name. It was home to a federal animal-disease lab. In Bitten, Kris Newby, a science writer who had Lyme herself, works through the papers of Willy Burgdorfer, the scientist who identified the Lyme bacterium in 1982. She argues that U.S. military research on ticks and insects as possible weapons deserves far more scrutiny. Some readers believe that research may have helped start or spread the Lyme epidemic.

What scientists say

Lyme bacteria are very old. Traces were found in the 5,300-year-old “Iceman” found in the Alps, in mice collected on Cape Cod in 1894 and in ticks collected on Long Island in 1945. Tick researcher Sam Telford of Tufts University says genetic data do not support a single starting point for Lyme in North America. He says the main reason there is so much Lyme today is that forests were allowed to grow back.

What the record shows

• In 2019, the U.S. House voted to ask the Pentagon whether it experimented with ticks and insects as weapons between 1950 and 1975. That request did not become law.
• On December 18, 2025, the defense bill for fiscal year 2026 became law. It orders the Government Accountability Office (GAO), the investigative agency of Congress, to review Defense Department research on ticks and tick-borne disease from 1945 to 1972, including work done with the National Institutes of Health and the Department of Agriculture. The review must look at whether any ticks were released outside a facility and whether any records were destroyed. The report is due by December 18, 2027.

Our history of Lyme disease has the full timeline.

2. Do the standard Lyme tests work?

In short: The standard blood test works well at some stages and poorly at others. Everyone agrees it often misses Lyme in the first weeks. People disagree about how much to rely on it after that.

What health agencies say

CDC recommends a two-step blood test using FDA-cleared tests. The test looks for antibodies, which your body takes weeks to make. CDC says the tests can be falsely negative during the first 4 to 6 weeks after infection. The 2020 IDSA/AAN/ACR guideline says a typical Lyme rash is diagnosed by looking at it, without a test. CDC also warns against tests that have not been properly validated.

What many patients and ILADS say

Many patients say they were told a negative test meant they did not have Lyme, even though they were sick. ILADS, a medical society that disagrees with the mainstream guideline, calls Lyme a clinical diagnosis based on your history and an exam, supported by lab tests when needed, and warns against relying too much on tests.

What this means for you

A negative test early on does not always rule Lyme out. Ask when the test was done and what it can and cannot show. See our Lyme disease test guide.

3. Is “chronic Lyme” real?

In short: Everyone agrees the symptoms are real. The fight is about what causes them.

What health agencies say

CDC says some people have fatigue, body aches or trouble thinking after Lyme treatment, and that the cause is unknown. It calls this post-treatment Lyme disease syndrome (PTLDS). CDC discourages the term “chronic Lyme disease” because it suggests an ongoing infection, which has not been shown.

What many patients and ILADS say

Patient groups such as LymeDisease.org argue that many people are diagnosed late, that tests can miss infection, and that bacteria may survive in some people. ILADS says the infection can persist after standard treatment and contribute to lasting symptoms.

Read the full picture in Is chronic Lyme disease real?

4. How long should antibiotics last?

In short: One side uses short courses and has trials behind it. The other allows longer courses when a doctor thinks they may help.

The mainstream guideline

The 2020 guideline from IDSA, AAN and ACR, which CDC follows, uses short antibiotic courses. It recommends against more antibiotics for lasting general symptoms when there is no clear sign of new infection or treatment failure. NIH-funded trials reported in 2001 found that intensive antibiotic treatment did not help long-term symptoms.

The ILADS guideline

The 2014 ILADS guideline allows longer courses and leaves more room for each doctor’s judgment. It recommends retreatment when a lasting infection is judged possible and quality of life is affected. ILADS itself rates the evidence behind its recommendations as very low quality.

See both side by side in IDSA vs ILADS. Never change your treatment without talking to your own doctor.

5. Why do doctors’ groups disagree?

In short: Two medical societies looked at the same research and reached different conclusions. The fight even reached a state attorney general.

In 2006, Connecticut Attorney General Richard Blumenthal opened an investigation into how the Infectious Diseases Society of America (IDSA) wrote its Lyme guidelines, raising conflicts of interest and whether different medical opinions were fairly considered. To end the investigation, IDSA agreed to an independent review. In 2010, a nine-member panel voted unanimously that the 2006 guidelines needed no changes.

Today there are two main guidelines: the 2020 IDSA/AAN/ACR guideline and the 2014 ILADS guideline. Doctors who follow the ILADS approach are often called “Lyme-literate” doctors by patients. Beat Lyme does not endorse either approach.

6. What happened to the first Lyme vaccine?

In short: There was a human Lyme vaccine in the U.S. It was pulled in 2002, and people still argue about why. A new one is under review in Europe.

LYMErix was approved by the FDA in 1998. On February 26, 2002, its maker, GlaxoSmithKline, withdrew it, citing poor sales. Demand had dropped after negative news coverage about possible side effects and lawsuits. The American Lyme Disease Foundation says those concerns were unfounded. Some patients still feel strongly the other way.

In March 2026, Pfizer and Valneva reported about 73% efficacy for a new vaccine in a large trial, although the main result fell just short of the trial’s pre-set statistical target because fewer cases occurred than expected. The European Medicines Agency began its formal review in August 2026. See our Lyme vaccine guide.

7. How common is Lyme, and can it be missed?

In short: Lyme is common, so chances are you know someone who has had it. It can also be missed or mistaken for something else, and the reverse happens too.

How many people get it

CDC estimates that about 476,000 people may be diagnosed and treated for Lyme disease in the U.S. each year, based on insurance records. CDC says this may be an overestimate, because a billing code does not always mean a confirmed case. States reported 89,468 cases in 2023, which is an undercount, because many cases are never reported. We think the true number likely falls somewhere in between. Either way, it is common enough that chances are you know someone who has had it.

Why Lyme can go unnoticed

• The tick is tiny. Young blacklegged ticks (nymphs) are about the size of a poppy seed and easy to miss, so many people never know they were bitten.
• Not everyone gets the rash. CDC says the typical Lyme rash appears in more than 70 percent of people with Lyme, so some people never see it.
• Early symptoms look like the flu. Fever, chills, headache, tiredness and aches are common in many illnesses.
• Early tests can be negative. Antibodies take weeks to show up.

Mistakes in both directions

Joint pain, fatigue, headache and poor sleep are common in many conditions. So Lyme can be mistaken for something else, and other illnesses can be wrongly labeled as Lyme. Patient groups worry most about missed cases. Many mainstream experts worry about people being treated for Lyme they do not have. Both happen.

Learn more in How common is Lyme disease? and Lyme disease and other conditions.

8. Co-infections, mold and other conditions: why it gets complicated

In short: One tick can carry more than one germ, and Lyme symptoms overlap with other illnesses. Some of these links are well established. Others, like mold, are hotly debated.

Co-infections

The same blacklegged tick can carry other germs besides the Lyme bacterium, depending on where you live. They include the germs behind anaplasmosis and babesiosis, Borrelia miyamotoi, Powassan virus and one form of ehrlichiosis. Most people with Lyme do not have a co-infection. But a high fever, certain blood test abnormalities, or a fever that continues during Lyme treatment are reasons to check for one in areas where these infections occur, according to the 2020 IDSA/AAN/ACR guideline. See Lyme disease co-infections.

Other conditions that overlap

Lingering Lyme symptoms overlap a lot with long COVID, ME/CFS (myalgic encephalomyelitis/chronic fatigue syndrome) and fibromyalgia. Some people also report conditions such as POTS (a problem with heart rate when standing) after Lyme. Whether Lyme can trigger these conditions is still being studied.

Mold

Mold can cause real health problems, mostly allergy-like symptoms such as a stuffy nose, coughing, wheezing and asthma flares, according to CDC. Some practitioners go further. They say “mold toxicity” or a condition they call CIRS (chronic inflammatory response syndrome) can make Lyme recovery harder. Medical toxicologists disagree: in a 2025 position statement, the American College of Medical Toxicology said there is no documented evidence that breathing indoor mold or mycotoxins causes chronic toxic illness, and called testing and treatment based on “mold toxicity” unproven. A 2015 CDC report warned that urine mycotoxin tests may not be valid. There is no established evidence that mold causes or worsens Lyme. See Lyme disease and mold.

What this means for you

If you are not getting better, it is fair to ask your provider about co-infections and other possible causes. Your own symptom record helps here.

9. Are we doing enough to prevent Lyme?

In short: The enemy is not far away in the woods. Ticks live where we live, including our own backyards. Many patients and advocates say not enough is being done, and that people look away because the subject is heavy.

The tick is in our backyard

Many people picture tick bites happening deep in a forest. But CDC specifically reminds families to check for ticks after time in their own backyard. Ticks like shade and moisture: the edge where the lawn meets the woods, leaf piles, stone walls and overgrown corners. Kids playing, gardening and walking the dog all count.

Even in big cities

Ticks are not only a country problem. New York City’s health department says Lyme disease, anaplasmosis and babesiosis are trending up in the city, with 2,928 Lyme cases in 2025 (preliminary). Most of those people were likely infected while traveling outside the city. But blacklegged ticks live in parks on Staten Island and in parts of the Bronx, such as Pelham Bay Park, and a few have been found in northern Manhattan, eastern Queens and Brooklyn. In a Columbia University-led study of 24 parks across all five boroughs, researchers found blacklegged ticks in 17 of them, and on average about 1 in 4 young ticks carried the Lyme bacterium.

What many people say

Patient advocates say prevention gets far too little attention for a disease this common. When the Kay Hagan Tick Act was renewed in September 2026, the Center for Lyme Action called for more federal investment in prevention, research, diagnosis, treatment and public health. And Americans have had no human Lyme vaccine since 2002.

What is being done

• On May 29, 2026, HHS announced a plan with the stated goal of cutting Lyme cases by 25% by 2035, compared with 2022.
• In September 2026, HHS announced nearly $3 million for pilot projects to kill ticks on deer and rodents.
• The renewed Kay Hagan Tick Act allows up to about $30 million a year for tick research centers and state programs, but Congress still has to approve the money each year.

Prevention is also harder than it sounds. In a four-year study of 24 neighborhoods in New York, yard treatments cut the number of ticks, but they did not significantly reduce tick encounters or tickborne illness in people. (Tickborne illness in outdoor pets was lower.) That is why everyday habits still matter so much.

Why it is easy to look away

Lyme is heavy to think about. The tick is tiny, the illness can be invisible, and the science is argued over. It is human to push it out of mind until it touches you or someone you love. But a little awareness is one of the simplest protections there is.

Our pets are part of it too

Dogs, cats and horses go where ticks wait, and ticks can ride into the house on them. Dogs can get Lyme disease: most exposed dogs never get sick, but some get a fever, low energy and lameness that moves from leg to leg. Unlike people, dogs have a Lyme vaccine. Vets recommend it based on where you live and how much your dog is around ticks, and it does not replace tick control. Illness from Lyme is rare in cats, but ticks still matter. Ask your vet about a year-round tick preventive, check your pets after time outdoors, and never use dog tick products on cats: some contain permethrin, which is dangerous for cats.

See Lyme disease in dogs, the Lyme vaccine for dogs, Lyme disease in cats and Lyme disease in horses.

What you can do today

• Use an EPA-registered insect repellent and treat clothes and gear with permethrin.
• Check yourself, your kids and your pets for ticks after time outdoors, including the backyard.
• Shower within two hours of coming inside, and tumble dry clothes on high heat for 10 minutes.
• Put a 3-foot strip of wood chips or gravel between your lawn and the woods, and keep the grass short.
• Remove an attached tick as soon as you find it.

See our Lyme disease prevention guide and how to tick-proof your yard.

10. Are ticks only a problem in the Northeast?

In short: Lyme is most common in the Northeast, the mid-Atlantic and the upper Midwest. But ticks live across the country, Lyme cases are reported nationwide, and a warming climate may be helping ticks spread.

Ticks are everywhere

In the U.S., Lyme is spread mainly by the blacklegged tick in the eastern half of the country and by the western blacklegged tick along the Pacific coast, CDC says. Other kinds of ticks, which spread other diseases, live in almost every region. Every state that tracks Lyme recorded cases in 2023. In some states with low numbers, many of those people were infected while traveling. And where Lyme is less familiar, it may be less likely to be suspected and tested for. Lyme is also spreading west and south: West Virginia now has one of the highest rates in the country.

The role of a warming climate

The U.S. Environmental Protection Agency (EPA) says studies show climate change has contributed to the expanded range of ticks, and that warming is projected to increase the areas where ticks can live. Blacklegged ticks are mostly active above about 45°F, so shorter, milder winters could mean more weeks each year when ticks are out. EPA says the spread of ticks in some northern states may be more related to a warming climate.

EPA also stresses that climate is only one of many factors, along with deer and other animals that ticks feed on, how people use the land, and how aware doctors and patients are. It says its data cannot show how much of the rise in Lyme is due to climate change.

What this means for you

Wherever you live or travel, tick checks matter. If you get sick after a trip, tell your healthcare provider where you went. See Lyme disease by state, where ticks live and travel and Lyme disease.

How to make up your own mind

1. Look for the source. A study, a law or an official record counts for more than a headline or a post.
2. Separate what is documented from what is suggested. Both matter, but they are not the same thing.
3. Ask who is speaking. Doctors, companies, authors and advocacy groups all have points of view.
4. Notice where both sides agree. The symptoms are real, ticks spread the disease, and early treatment matters.
5. Know your own body. Nobody knows your body like you do. Pay attention to your symptoms and keep a simple record: what you feel, when it started, what makes it better or worse, and any tick bites or rashes. Your own notes are evidence too.
6. Talk it through. Bring your questions to a healthcare provider you trust. Our visit guide can help.

Frequently asked questions