April 22, 2024
8 months ago

Delayed Headaches Occurring After COVID Shot Raise Red Flags: Researcher

Nurse practitioner Sarah Rauner fills a syringe with the Pfizer Covid-19 vaccine to be administered to children from 5-11 years old at the Beaumont Health offices in Southfield, Michigan on November 5, 2021. (Photo by JEFF KOWALSKY / AFP) (Photo by JEFF KOWALSKY/AFP via Getty Images)

The Epoch Times| by Mary Gillis | August 26, 2023

DP News Summary Talking Points:

  • A study conducted in Iran and published in Frontiers in Neurology highlights that headaches after COVID-19 vaccination are common, with prevalence rates of 36.5% after the first dose, 23.3% after the second dose, and 21.7% after the third dose.
  • Delayed headache onset after vaccination is considered a potential “red flag” and could indicate serious conditions such as cerebral venous thrombosis (CVT), acute myelitis, and intracerebral hemorrhage. Individuals with postvaccination headaches following COVID-19 infection face higher odds of developing such headaches.
  • The study suggests that certain groups, including those with primary headaches, post-COVID-19 headaches, and prior vaccine-related headaches, are at a higher risk of experiencing postvaccination headaches. Understanding these characteristics is crucial for accurate diagnosis and differentiation from more severe conditions, such as CVT.

Reports of headaches after receiving the COVID-19 vaccine have been common. While most are nonserious and treatable, researchers in Iran who conducted a new study published in Frontiers in Neurology warn that delayed headache onset “should be considered a red flag.”

According to a survey of nearly 2,000, primarily female respondents, the prevalence of headaches after the first, second, or third vaccine doses was 36.5 percent, 23.3 percent, and 21.7 percent, respectively.

Some people are at high risk of postvaccination headaches, including people with primary headaches, post-COVID-19 headaches, headaches following a previous dose, postvaccination fever, and those who received vector vaccines (such as AstraZeneca and the Johnson & Johnson vaccines), according to the researchers.

Headache After Infection Versus Vaccination

Researchers also highlighted the differences in characteristics of people who reported headaches after an infection versus a vaccination.

Among people with post-COVID infection headaches, 59 percent were migraine-like, and 31.4 percent were tension-type headaches.

Tension-type headaches were more prevalent for people with postvaccination headaches than migraine-like headaches. Participants’ headaches were mainly bilateral, moderate, and pressing, affecting the entire head or multiple regions.

Could Be a Sign of Serious Conditions

Most participants said their headaches were mild, and the authors pointed out that headaches are common adverse events reported with other vaccines.

However, these headaches resulting from COVID-19 vaccination may lead to dangerous consequences.

Postvaccination headaches “can also be a sign of life-threatening conditions, including cerebral venous thrombosis (CVT), acute myelitis, and intracerebral hemorrhage,” the researchers wrote. “Post-vaccination headaches usually initiate less than a day after vaccination, and delayed headache onset should be considered a red flag for serious conditions, such as vaccine-induced CVT.”

The study findings also showed that developing headaches following COVID-19 increased the odds of developing postvaccination headaches. While the mechanism behind the reaction remains unknown, the authors suggested it might be related to what’s called a cytokine-mediated pathomechanism. This is the pathway where cytokines regulate immunity and inflammation.

A 2022 study (pdf) published in the Journal of Clinical Medicine showed similar results. Authors found postvaccine headaches may be associated with the release of cytokines, particularly in people diagnosed with migraines. Of 841 respondents, over 66 percent experienced migraines one hour to seven days after their first vaccine dose. Over 60 percent said they experienced a headache one hour to seven days after their second dose. Over 50 percent said the headache was severe.

Neurological Side Effects

A comprehensive 2022 review found several neurological side effects that tear through the brain, spine, and nerves after COVID-19 vaccination. Most of them occurred in older adults and people with autoimmune disorders. Side effects for adenovirus-based vaccines included:

  • Spinal cord inflammation.
  • Damage to the outer, protective layer of the spinal cord.
  • Eye inflammation in one or both eyes.
  • Brain inflammation or swelling.
  • Guillain-Barré syndrome.
  • Bell’s palsy.
  • Multiple sclerosis.
  • Ischemic stroke.
  • Sudden crippling pain in the arms and shoulders.
  • Herpes zoster.
  • Ringing and nerve damage in the ears.

Researchers of a report published in the Journal of Headache and Pain also list CVT as a dangerous, potentially life-threatening side effect.

What Is Cerebral Venous Sinus Thrombosis?

Cerebral venous thrombosis (CVT) happens when a blood clot forms in the brain’s blood vessels, preventing blood from draining out. The clot may then break, causing blood to leak into brain tissues. This could result in a hemorrhage, which can lead to a stroke.

Symptoms of cerebral venous thrombosis may vary depending on the location of the blood clot. Physical symptoms that may occur are:

  • Headache.
  • Blurred vision.
  • Fainting or loss of consciousness.
  • Loss of control over movement in part of the body.
  • Seizures.
  • Coma.

“Delayed onset of headache following an adenovirus vector-based COVID-19 vaccine is associated with CVT,” according to the Journal of Headache and Pain report authors. “Patients with new-onset headache, 1 week after vaccination with an adenovirus vector-based vaccine, should receive a thorough clinical evaluation and CVT must be ruled out.”

“Understanding the characteristics and risk factors associated with these headaches can help physicians diagnose these headaches and distinguish them from more serious causes (such as CVT),” researchers from the Frontiers in Neurology study wrote. More studies taking confounding factors into account concerning postvaccination headaches are needed, the authors concluded.


Continued efforts to distinguish factors associated with these headaches—specifically prolonged headaches following vaccination—are needed, according to the study authors.

To report COVID-19 vaccine side effects, visit the Vaccine Adverse Events Reporting System’s website.

Source: Delayed Headaches Occurring After COVID Shot Raise Red Flags: Researcher (theepochtimes.com)

Don't Miss