Written by Dr. Valentina Quintana MD on
February 5, 2022
Reading Time: 7 minutes

Medically Reviewed by our Medical Affairs Team

Written by Dr. Valentina Quintana MD on:

Did you just get vaccinated and feel like you’ve been hit by a truck? Are you having trouble thinking straight?

If so, you may be experiencing vaccine brain fog. This is a condition that is caused by some vaccines, and it can lead to a range of unpleasant symptoms.

In this blog post, we will discuss the causes, symptoms, and remedies for brain fog after vaccine. We hope that this information will help you get your life back on track!

What exactly is vax brain fog?

Vax brain fog is a condition that is caused by some vaccines, especially those that have been recently administered for the Covid-19 virus.

Brain fog after Covid vaccine and other types of vaccines can lead to a range of unpleasant ongoing symptoms, including difficulty thinking straight and cognitive fatigue, which makes you feel like your brain cells are overworked.

The symptoms of vax mental fog can vary from person to person.

Some people may experience only a few minor symptoms, while others may have more severe lingering symptoms that significantly impact their quality of life.

It is important to note that the symptoms of vax mental fog may occur after any vaccine, not just those for Covid-19. 

What are the causes of vaccine brain fog?

Vax mental fog is caused by a vaccine, which may occur after any vaccine. It is not limited to vaccines for Covid-19 or other viral illnesses like influenza (the flu).

According to the Centers for Disease Control and Prevention (CDC), a vax cognitive fog is typically caused by vaccine adjuvants, which are substances that are added to vaccines in order to enhance the vaccine’s effectiveness on a severe or acute infection.

These vaccine adjuvants can include aluminum salts (such as aluminum hydroxide or aluminum phosphate), squalene oil emulsions, and other materials like liposomes.

These vaccine adjuvants are known to cause brain fog in a small subset of vaccine recipients, especially those with existing health problems like diabetes or heart disease, or neurological complications.

What are the symptoms of brain fog after vaccine?

The symptoms of mental fog after vaccine can vary from person to person.

Some people may experience only a few minor cognitive fog symptoms, while others may have more severe vaccine-induced encephalopathy (VIE) that significantly impacts their quality of life.

Common examples of vax mental fog symptoms include trouble thinking straight and cognitive fatigue.

Other symptoms may include:

  • feeling overwhelmed
  • decreased energy
  • mood changes
  • difficulty concentrating
  • difficulty remembering things
  • and feeling confused.

These symptoms can significantly impact a person’s quality of life and make it difficult to perform everyday tasks.

Is there a diagnosis for brain fog after Covid vaccine or any other vaccines?

There is no specific diagnosis for mental fog after vaccine. However, doctors may use the term “vaccine-induced encephalopathy” (VIE) to describe this condition.

This is a general term that is used to describe any type of neurologic damage that is caused by a vaccine. VIE can include symptoms like brain fog after vaccine.

VIE may also include other vaccine-induced symptoms like seizures and convulsions, which are more severe than a mental fog. 

Is there a treatment for brain fog after a vaccine?

There is no cure for vax mental fog, but some people have found that taking vitamin B12 can help alleviate their symptoms.

B12 is a vitamin that has been shown in scientific studies to help reduce vaccine-induced encephalopathy (VIE) and brain fog after vaccine, especially when taken in high doses.

If you are experiencing vax mental fog and want to try taking vitamin B12 supplements for relief, we recommend starting with a dose of 500-1000 mcg per day.

You can find vitamin B12 supplements at most pharmacies or health food stores.

If you are experiencing more severe symptoms, like seizures or convulsions, please consult your doctor immediately.

What should I do if I am experiencing vax mental fog?

If you are experiencing any of the symptoms of vax cognitive fog, we suggest talking to your doctor.

Your doctor may be able to help you figure out if the symptoms you are experiencing are related to a vaccine and may be able to provide some relief.

If you are experiencing more severe symptoms, like seizures or convulsions, we strongly recommend that you consult your doctor immediately. 

If it’s a mild mental fog after, you might want to try taking vitamin B12 supplements and drinking lots of water.

Also, there are a few things you can do to help prevent vax brain fog from occurring in the first place:

  • Make sure you are well-hydrated before and after receiving a vaccine. Drink plenty of water before and after your vaccine appointment.
  • Avoid consuming alcohol for at least 48 hours before vaccine appointment.
  • Ensure that your blood pressure is stable before taking the shot to avoid aggravating blood clots.
  • If possible, wait until after receiving vaccine to drive or operate heavy machinery.
  • Avoid strenuous exercise (especially if experiencing mental fog symptoms) within 24 hours of vaccine administration.
  • Do not travel long distances by plane or car within 24 hours of vaccine appointment. 
  • Avoid taking any medications (except those prescribed by your doctor) for at least 72 hours before vaccine administration. 
  • If you are pregnant or nursing, consult with your doctor before getting vaccinated.

These are just some general tips to help prevent vax mental fog. For more specific advice, please talk to your doctor.

Home Remedies for Cognitive Fog After Vax

If you are experiencing mental fog after getting your vaccine shot, here are some home remedies you can try to help alleviate your symptoms:

  • Drink lots of fluids, especially water—dehydration can worsen mental fog symptoms.
  • Get plenty of rest—fatigue can aggravate your symptoms.
  • Avoid caffeine and alcohol, which can make brain fog worse.
  • Stay cool and avoid excessive heat, which can aggravate symptoms of mental fog.
  • Try taking a Vitamin B12 supplement or eating foods rich in Vitamin B12 (such as fish and eggs). 
  • Try using a cooling pillow or ice pack to help soothe your symptoms.
  • Keep a journal and make a note of things that seem to worsen your symptoms or make them better.
  • Practice some stress-relieving techniques like yoga or meditation.

If you are experiencing more severe vaccine side effects, like seizures and convulsions, please consult with your doctor immediately.

What causes the lingering symptoms of Covid vaccines?

The vaccine side effects are usually only temporary and go away on their own within a few days.

However, some people experience lingering symptoms, also known as long covid symptoms, such as cognitive fog that lasts for weeks or even months after their vaccine appointment.

This is because vaccine side effects can be caused by your immune system’s response to foreign substances in vaccines (antigens).

The vaccine triggers an immune response that produces antibodies against these antigens.

However, it takes time for your body to produce enough antibodies to protect you from the lingering virus.

In some cases, immune responses can cause inflammation and irritation that lead to vaccine side effects like mental fog and fever. 

Take note that these vaccine side effects are expected even among the popular vaccines for Covid, such as:

Why does the vaccine help?

The vaccine helps to protect you from the virus by triggering your immune system to produce antibodies.

These antibodies will help to protect you against the virus in the event that you are exposed to it.

The vaccine also contains an adjuvant, which is a substance that helps increase your body’s response to the vaccine and helps improve its effectiveness in preventing the increased risk of a severe or acute infection. 

What are the other side effects of vaccines?

Other vaccine side effects include headache, nausea, vomiting, and fatigue.

However, in some cases, vaccine side effects can be more severe and even life-threatening.

Some people have experienced seizures after receiving a vaccine dose. Other vaccine side effects that you should look out for include:

  • Severe rash or hives (a sign of an allergic reaction)
  • Difficulty breathing
  • Dizziness or loss of consciousness
  • High fever (over 102 degrees Fahrenheit)
  • Severe headache that does not go away with over-the-counter pain medications, like Tylenol or Advil. 

What can I do to prevent vaccine side effects?

The Centers for Disease Control and Prevention recommends that the best way to prevent vaccine side effects is by following the instructions that come with your vaccine.

If you are experiencing vaccine side effects, ask a doctor or pharmacist for advice on what to do next.

Do not take any medications (except those prescribed by your doctor) for at least 72 hours before vaccine administration. 

This includes acetaminophen (Tylenol), ibuprofen (Advil, Motrin), and aspirin.

If you are experiencing vaccine side effects that do not go away after 72 hours, contact your doctor immediately for further instruction. 

Do not get any vaccines if you have had a serious allergic reaction to a vaccine or any of its ingredients in the past.

Which is better—vaccines or natural immunity? 

Natural immunity is the body’s ability to fight off certain diseases on its own.

It develops when you are exposed to a virus or vaccine and produces antibodies that protect you from future infection with that same disease.

The vaccine helps produce antibodies against viruses, which can prevent them from attacking your immune system in the first place. 

So, in a way, both vaccines and biological immunity are helpful in protecting you from severe illness.

Which is more effective—vaccines or natural immunity?

The vaccine is more effective than natural immunity because it helps to produce antibodies against viruses before you are exposed to them.

This can help protect you from the virus, even if you are exposed to it later on in life.

Biological immunity is only effective against the vaccine antigens.  

So, if you received vaccine antigen A, it will only protect you from vaccine antigen A. 

There are also some people who cannot receive certain vaccines because of allergies or health conditions, such as severe physical and neurological complications. 

These individuals may benefit more from natural immunity than others do.

So, what have we learned?

The vaccine helps protect you from the virus by triggering your immune system to produce antibodies that fight it off.

The vaccine does not directly cause mental fog, but vaccine-associated brain fog may exist in some individuals after receiving a vaccine dose. 

This condition usually goes away within two to three weeks of vaccination and is not serious if symptoms persist for more than three weeks or worsen after vaccination.

If you are experiencing vax brain fog, there is no need to worry as it is not a serious condition.

However, contact your doctor immediately if the symptoms persist for more than three weeks or worsen after vaccination. 

If you want to learn more about brain fog and how to clear it, check out these helpful articles and feel free to join this online community of brain health professionals and advocates.

Join The Mental Health Community You've Been Dreaming Of


This discord family is a safe place where we can all (anonymously if we choose) talk about and seek help for what is going on in our heads.

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