COVID-19 may increase the risk of Alzheimer’s disease, especially for those who experience a severe infection. COVID-19 causes inflammation and other physiological changes in the brain that are associated with Alzheimer’s disease.

The connection goes both ways, however. People with existing Alzheimer’s disease also have an increased risk of contracting COVID-19, and may be more likely to experience more severe short- and long-term health effects from it.

It’s important to take steps to lower the risk of contracting COVID-19 to help protect yourself and others.

Several studies have identified a connection between COVID-19 and increased diagnoses of Alzheimer’s disease.

The exact mechanisms are still being studied, but researchers have suggested a few possible reasons why COVID-19 may make Alzheimer’s disease more likely.

For example, neuroinflammation (inflammation of the brain and spinal cord) occurs in both Alzheimer’s disease and COVID-19.

When SARS-CoV-2, the virus that causes COVID-19, infects someone, it can damage the blood-brain barrier. This barrier prevents pathogens like viruses from entering the brain, but viruses like SARS-CoV-2 can disrupt it, allowing pathogens to enter and cause inflammation and damage.

COVID-19 may also damage neurons and lead to an increase in certain proteins, like amyloid beta (Aβ), that play a role in the development of Alzheimer’s disease.

There is a higher incidence of Alzheimer’s disease diagnoses within a year of COVID-19 infection, but so far, there isn’t any evidence showing that Alzheimer’s disease is affecting younger people. It’s not known what the risk of Alzheimer’s disease is for people who have COVID-19 when they’re younger.

For people older than 50 or who have a family history of Alzheimer’s disease, avoiding COVID-19 infection is essential.

Compared to people without Alzheimer’s disease, people with the condition have both an increased risk of developing COVID-19 and a higher risk of worse outcomes from the infection, including rapid cognitive decline and death.

A 2023 research review suggests that a few possible reasons for these increased risks, such as:

  • Age: People with Alzheimer’s disease are typically older, and increasing age is also a risk factor for COVID-19. The aging process causes certain psychological changes, such as weakening of the blood-brain barrier, that may make someone more susceptible to brain inflammation when they develop COVID-19.
  • Cognitive effects of Alzheimer’s disease: Alzheimer’s disease can make it more difficult for someone to remember protective measures, like masking in public or getting the COVID-19 vaccine, that lower their risk of developing the infection.
  • Comorbidities: People with Alzheimer’s disease may also have other conditions, such as diabetes or high blood pressure, that may worsen the outcomes of a COVID-19 infection.

There are several steps you can take to reduce your risk of COVID-19.

First, it’s important to get the most current COVID-19 vaccine. Studies included in another 2023 research review suggest that vaccination may reduce the risk of cognitive decline when administered before or after a COVID-19 infection, possibly by reducing inflammation and eliminating the virus from the body.

Large studies have also found that mRNA vaccines are safe and effective at reducing the risk of death from COVID-19.

Other protective measures can also help reduce COVID-19 risk:

  • Wear a mask in public.
  • Wash your hands frequently, using soap and water.
  • Try to avoid contact with people who are sick or may have been in contact with someone with COVID-19.

If you’re caring for someone with Alzheimer’s disease, these measures can also help protect them. You can help them wear a mask, get their vaccines, and avoid situations where they may be more likely to contract COVID-19.

If you or someone you know develops COVID-19, it’s best to get medical treatment right away to lower your risk of progressing to a severe infection.

Certain medications, like nirmatrelvir-ritonavir (Paxlovid), have been approved by the Food and Drug Administration (FDA) to help treat mild to moderate COVID-19 in people who have a higher risk of progression to severe COVID-19. Paxlovid may help lower the risk of brain inflammation and other post-COVID-19 complications.

People who already have Alzheimer’s disease have a higher risk of progression to severe infections and can benefit from these medications.

Not everyone is eligible for medications like Paxlovid, so it’s best to talk with a healthcare professional to understand your options based on your medical history.

Next steps

If you or someone you know tests positive for COVID-19, talk with a doctor as soon as possible.

You may want to visit a local urgent care center for mild to moderate symptoms. If you don’t already have a primary care doctor, you can also try using Healthline’s FindCare tool to locate one in your area.

Severe symptoms, such as confusion or difficulty breathing, require treatment at an emergency room.

People who develop COVID-19 may have a higher risk of developing Alzheimer’s disease within a year due to brain inflammation and other changes caused by the infection. Conversely, people with Alzheimer’s disease can be more likely to develop COVID-19 and experience more severe outcomes.

It’s essential to take steps to lower your risk of developing COVID-19 and get medical help as soon as possible if you test positive.