Unlike a cold or the flu, Alzheimer’s disease isn’t contagious. Because Alzheimer’s isn’t caused by viruses or bacteria, you can’t catch it by being around someone who has it.

Some outdated medical procedures from the 1980s caused some confusion about the transmission of Alzheimer’s disease. But today, scientists agree there’s no reason to worry about spreading Alzheimer’s among friends and family. Read on to learn more.

Why Are People Worried About Spreading Alzheimer’s?

Rumors about Alzheimer’s disease being contagious come from a medical procedure that was done in the 1980s to treat short stature. The procedure involved giving people human growth hormone (HGH) taken from the brains of cadavers (people who had died). In January 2024, researchers discovered that a few of those brain samples may have been contaminated. This raised concerns that Alzheimer’s disease might have been passed from donors to patients, but this has not been proven, and only a few cases were studied.

It’s important to know that this procedure for short height is no longer used today. Now, doctors use a safe, synthetic form of growth hormone for people who need it. So there’s no need to worry about this happening again.

To test whether Alzheimer’s disease can spread, researchers injected mice with brain tissue containing amyloid proteins from humans who have Alzheimer’s disease. These mice later developed amyloid buildup (a sign of Alzheimer’s disease) in their brain tissue. The study found that injecting amyloid into the mice’s blood could cause it to travel to their brains. It’s important to remember this happened in a lab experiment with animals, and it doesn’t show how Alzheimer’s works in people.

New research says there’s no evidence that Alzheimer’s can be spread through blood transfusions, surgical procedures, or being around someone who has it.

What Causes Alzheimer’s Disease?

Alzheimer’s can’t be transmitted from person to person, even with intimate contact. Instead, Alzheimer’s disease develops over time because of a mix of risk factors, including age, genetics, lifestyle, and environmental factors. Scientists believe there’s no single cause — it’s probably caused by a combination of different factors.

Age

Age is by far the biggest risk factor for Alzheimer’s disease. The risk of having Alzheimer’s increases dramatically with age. Fewer than 10 percent of cases happen in people under 65. About 1 in 13 people between the ages of 65 and 84 has Alzheimer’s disease. After age 85, that number rises to 1 in 3 people. Scientists are still trying to figure out how aging contributes to Alzheimer’s. It could be related to brain changes like shrinking, inflammation, and reduced energy in the brain.

Genetics

If you have a parent or sibling with Alzheimer’s disease, your risk of getting it is higher. That’s why experts believe that genes can play a role. Certain genes passed down in families may increase the chance of developing Alzheimer’s. One example is the apolipoprotein E (APOE) gene, which has been linked to Alzheimer’s disease. But having this gene doesn’t mean you’ll definitely get Alzheimer’s — it just means your risk is higher.

Other Health Conditions

Some medical conditions can also raise your risk of Alzheimer’s disease. These health issues can affect brain health directly or indirectly. They include:

• Brain injuries
• Depression
• Diabetes
• Hearing loss
• High blood pressure

Taking care of your overall health may help protect your brain. Getting good sleep, exercising regularly, eating a healthy diet, and avoiding smoking and alcohol can all help lower your risk of Alzheimer’s disease. Staying mentally active and spending time with others is also great for your brain.

Why It’s Crucial To Debunk Alzheimer’s Myths

Myths about Alzheimer’s can be harmful. Clearing up these misunderstandings helps protect people’s health. For example, the myth that Alzheimer’s can be spread through things like brain surgery can make people afraid to get important treatments. However, there’s no good reason to avoid brain surgery because of a fear of Alzheimer’s disease. Today’s surgeries follow strict sanitation standards, and the old medical procedure that caused confusion isn’t performed anymore.

Another myth is that Alzheimer’s could spread through blood transfusions. But large studies of 1.5 million people in Sweden and Denmark found no link between blood transfusions and dementia. These rumors about the safety of blood transfusions can be dangerous if they stop people from getting lifesaving care.

It’s normal to be worried about a serious disease like Alzheimer’s. But spreading misinformation can cause more harm. For example, saying Alzheimer’s is contagious may lead people to avoid friends or family with dementia. Research suggests that this social isolation can actually make memory loss and cognitive decline worse in people with Alzheimer’s disease.

The Real Dangers of Social Isolation and Stigma

People with Alzheimer’s disease — and their caregivers — need social interaction, and may feel hurt when it’s missing from their lives. One caregiver on myALZteam shared, “I wish more would visit us while hubby is able to talk and visit.”

Another said, “I think people aren’t sure if they’ll say the wrong thing. Maybe invite them over or out to a picnic, and they’ll see they can enjoy you both, be themselves, and don’t have to tread carefully. We humans can so easily lose confidence when we wait for visitors who don’t come, or we want to visit but don’t know if it’s OK.”

If you haven’t heard from your friends since Alzheimer’s entered your life, try to give them the benefit of the doubt. They may not know how to be supportive. Or, they may feel nervous and confused — especially if they’ve heard myths, like that Alzheimer’s is contagious. Reaching out and being patient with others’ questions or concerns can help them feel more comfortable.

One myALZteam member said, “I always think that if you invite them, people will cross the bridge, and hopefully you’ll end up with as many visitors as you’d like … the real friends will be queuing for entrance once they know they’re welcome.”

You can also find support beyond your existing friend group. People who have experience with Alzheimer’s or other types of dementia can help you feel less alone on your journey. You might find them through online groups or local events like fundraisers for Alzheimer’s disease. Ask your healthcare professional about any support groups near you.

Talk With Others Who Understand

On myALZteam, the social network for people with Alzheimer’s disease and their caregivers, members come together to ask questions, give advice, and share stories with others who understand life with Alzheimer’s disease.

What’s the latest news you’ve heard about the development of Alzheimer’s disease? What do you think other people misunderstand about Alzheimer’s? Share your thoughts in the comments below, or start a conversation by posting on your Activities page.