Besides respiratory manifestations, headache is a very common neurological symptom of COVID-19 for all age groups. Moreover, it is considered one of the most common side effects caused by COVID-19 vaccines. The severity of headache can vary widely and may require further investigation and treatment. 

How often is headache found in COVID-19 patients?     

Headache has been reported as one of the most frequently found symptoms of COVID-19. The prevalence of headache in COVID-19 patients is up to 30%. Headache tends to come on at the very start of the illness, within the first 7 days after being infected. Interestingly, most of these patients have had no prior medical history related to headache. Whilst headache alone is not probably related to COVID-19, headache presenting alongside other signs and symptoms, e.g. fever, cough, loss of taste/smell may be a potential indicator of COVID-19. 

What are the characteristics of COVID-19 associated headache?

Headache in COVID-19 develops rapidly after infection and the pain is usually moderate to severe. The headache typically does not respond to analgesics or recurs after the analgesics wear off.

The headache mostly appears as tension-like at the temporal area, forehead, around both eyes, or all over the head. Sometimes there can be throbbing pain or pulsating sensation. Bending the head forward, coughing, sneezing, and exertion can worsen the pain. The headache can last up to 2 weeks.

How can COVID-19 cause headache?

Based on current medical evidence, the causes of headache in COVID-19 may be attributed to two possible explanations:

  1. SARS-CoV-2 invades the brain through the nasal cavity and induces headache by the activation of the trigeminal nerve (5th cranial nerve). 
  2. SARS-CoV-2 stimulates the body to release inflammatory cytokines which directly affect the pain pathway in the brain, resulting in headache. 

How can headache caused by COVID-19 be distinguished from other types of headache?

Apart from headache, patients infected with COVID-19 normally manifest a wide range of signs and symptoms, extending from fever, cough, dizziness, loss of smell or taste, pain while swallowing, fatigue and weakness to shortness of breath. Nevertheless, sensitivity to light and sound might be an overlapping sign of headache caused by COVID-19 and migraine headache. In patients who have headache as their underlying condition, there might be a change in their headache characteristics. 

What is the incidence of headache after COVID-19 vaccination?

Headache has been reported as one of the most common side effects caused by COVID-19 vaccines worldwide, regardless of types or manufacturers. Overall, elderly people are less likely to have headache compared to young adults. Moreover, the administration of the second dose usually produces less undesired effects than the first dose. 

According to recent studies, the prevalence of headache after vaccination are as follow:

  • 6-18.7% for inactivated virus vaccine (CoronaVac)
  • 22.8-29.3% for viral vector vaccine (ChAdox1 nCoV-19; AstraZeneca)
  • 39-52% for mRNA vaccine (BNT162b2; Pfizer)

How can we treat headache after vaccination with COVID-19 vaccine?

In most cases, headache caused by COVID-19 vaccine usually alleviates and subsides within a week. If required, analgesic drugs, such as paracetamol may be used to provide symptomatic relief from post-vaccination headache. If headache persists or worsens after taking paracetamol, more potent painkillers, such as Non-Steroidal Anti-Inflammatory Drugs or NSAIDs might be considered.

In patients who have migraine headache as preexisting condition, paracetamol is recommended if migraine symptoms are aggravated after vaccination. NSAIDs or triptans may be considered if the headache is severe. Medical attention should be sought immediately if the headache progresses or does not improve after taking analgesics, or if there are other neurological abnormalities.

Reference: 

Dr. Kiratikorn Vongvaivanich

Neurologist (Sub-specialty: Headache Medicine), Neuroscience Center, Bangkok International Hospital.