If you’ve developed a headache after receiving a COVID-19 vaccine, you’re in good company. Headaches are among the most commonly reported side effects following vaccination, affecting a significant portion of vaccine recipients. While the throbbing or pressure in your head might be uncomfortable, it’s usually a sign that your immune system is responding to the vaccine exactly as it should.
According to clinical trial data and post-authorization surveillance, headaches occur in approximately 25-50% of people after COVID-19 vaccination, with rates varying by vaccine type and dose [1]. The good news is that these headaches are typically mild to moderate, respond well to over-the-counter pain relievers, and resolve within one to three days. Understanding what’s happening in your body—and knowing what symptoms warrant medical attention—can help you navigate this temporary discomfort with confidence.
Track your post-vaccine symptoms with our symptom diary
Keeping a record of your symptoms after vaccination can be helpful, especially if you experience headaches or other side effects. Our symptom diary helps you log the timing, severity, and duration of your headache, along with any other symptoms you notice. This information can be valuable if you need to discuss your experience with a healthcare provider or want to compare responses between vaccine doses. Of course, while tracking is useful, don’t hesitate to seek medical care if you’re experiencing severe or concerning symptoms.
Why does the COVID vaccine cause headaches?
The headache you experience after vaccination isn’t random—it’s a direct result of your immune system doing its job. When you receive a COVID-19 vaccine, your body begins producing antibodies against the spike protein found on the surface of the SARS-CoV-2 virus. This immune activation triggers an inflammatory response, which is what causes the familiar side effects many people experience.
During this process, your body releases signaling molecules called cytokines. These cytokines help coordinate your immune response, but they also cause inflammation that can lead to symptoms like headache, fatigue, muscle aches, and low-grade fever [2]. The headache is essentially a byproduct of your immune system ramping up its defenses.
This is why side effects like headaches are sometimes called “reactogenicity”—they reflect your body’s reaction to the vaccine. Importantly, these symptoms indicate that the vaccine is working, though it’s worth noting that people who don’t experience side effects are also developing protection. Everyone’s immune response is different.
How long do post-vaccine headaches typically last?
For most people, headaches after COVID-19 vaccination follow a predictable pattern:
Onset: Headaches typically begin within 12-24 hours after vaccination, though some people notice them within a few hours and others not until the next day.
Peak: Symptoms usually peak around 24-48 hours post-vaccination—this is often when the headache feels worst.
Duration: Most post-vaccine headaches resolve within 1-3 days. According to CDC data, the majority of side effects last no more than a few days [3].
Second dose and boosters: Many people experience more pronounced side effects, including headaches, after their second dose or booster shots. This is because your immune system already has some memory of the spike protein from the first dose and mounts a stronger response [4].
If your headache persists beyond 72 hours or is getting worse rather than better, it’s worth contacting your healthcare provider for guidance.
What helps relieve a post-vaccine headache?
The good news is that post-vaccine headaches typically respond well to standard headache treatments. Here are effective strategies for finding relief:
Over-the-counter pain relievers
Acetaminophen (Tylenol) and NSAIDs like ibuprofen (Advil, Motrin) or naproxen (Aleve) are generally safe and effective for post-vaccine headaches. The CDC states that you can take these medications to relieve symptoms after vaccination [3].
Important note: While it’s fine to take pain relievers after vaccination if you need them, some experts recommend avoiding them before vaccination, as there’s limited evidence about whether they might affect the immune response. Once you’ve been vaccinated, treating your symptoms is appropriate.
Hydration
Staying well-hydrated can help reduce headache severity. Dehydration is a common headache trigger on its own, and ensuring adequate fluid intake supports your body during the immune response.
Rest
Your body is working hard to build immunity. Getting adequate sleep and taking it easy for a day or two can help you feel better faster and may reduce overall symptom severity.
Cold compress
A cold pack applied to your forehead or the back of your neck may provide temporary relief, particularly if your headache has a throbbing quality.
Manage other symptoms
Headaches often occur alongside other side effects like fatigue or low-grade fever. Addressing these symptoms with rest and appropriate medication can help you feel better overall.
Are some people more likely to get headaches after vaccination?
Research and real-world data have identified some patterns in who experiences post-vaccine headaches:
Age
Younger adults tend to report more side effects, including headaches, than older adults. This likely reflects more robust immune responses in younger people [5]. However, this doesn’t mean the vaccine is less effective in older adults—they’re still developing protection.
Dose number
Second doses and booster shots typically produce more side effects than first doses. Your immune system “remembers” the first exposure and mounts a stronger response to subsequent doses.
Vaccine type
Different COVID-19 vaccines have slightly different side effect profiles. mRNA vaccines (Pfizer-BioNTech and Moderna) tend to have somewhat higher rates of reactogenic side effects compared to some other vaccine types, though all approved vaccines are safe and effective.
Pre-existing headache conditions
People who already experience migraines or frequent headaches may be more susceptible to post-vaccine headaches. Some migraine sufferers report that vaccination triggers a migraine attack [6]. If you have a headache condition, having your usual treatments on hand can be helpful.
Prior COVID-19 infection
Some studies suggest that people who previously had COVID-19 may experience more pronounced side effects after their first vaccine dose, as their immune system already has some memory of the virus.
When should I be concerned about a post-vaccine headache?
While the vast majority of post-vaccine headaches are harmless and temporary, certain symptoms warrant medical attention. Contact a healthcare provider if:
- Your headache is unusually severe—the worst headache of your life
- The headache persists for more than 72 hours without improvement
- You experience neurological symptoms like vision changes, confusion, difficulty speaking, weakness, or numbness
- You have persistent vomiting that prevents you from keeping down fluids
- You develop severe abdominal or leg pain
- You notice tiny blood spots under the skin (petechiae) or unusual bruising
- You develop shortness of breath or chest pain
These symptoms are rare but could indicate a serious reaction that requires immediate evaluation. In particular, severe headache combined with low platelets or blood clots was identified as a very rare complication (vaccine-induced immune thrombocytopenia and thrombosis, or VITT) associated with certain viral vector vaccines [7]. This condition is extremely rare but is treatable when identified early.
If you’re uncertain whether your symptoms are concerning, err on the side of caution and contact your healthcare provider or the facility where you were vaccinated.
Can I prevent post-vaccine headaches?
There’s no guaranteed way to prevent side effects, but some general strategies may help minimize their impact:
- Stay hydrated before and after your vaccination appointment
- Get a good night’s sleep before your appointment
- Eat a normal meal before getting vaccinated—don’t go on an empty stomach
- Plan for rest after vaccination, especially for second doses or boosters
- Have pain relievers on hand so you can treat symptoms promptly if they occur
- Avoid strenuous exercise for 24-48 hours after vaccination
Some people find that side effects are less bothersome when they’re able to rest and take it easy after vaccination. If possible, schedule your appointment before a day when you can take things slowly.
Moving forward after vaccination
A headache after COVID-19 vaccination, while uncomfortable, is a normal part of your body’s immune response. For most people, it’s a temporary inconvenience that resolves within a day or two—a small price to pay for the protection vaccination provides.
If you’re preparing for an upcoming dose, know that experiencing side effects after a previous dose doesn’t mean you’ll have the same experience again (though it’s certainly possible). And if this is your first time experiencing a post-vaccine headache, rest assured that it’s common, manageable, and typically short-lived.
Keep over-the-counter pain relievers handy, stay hydrated, rest when you can, and remember that your immune system is doing exactly what it’s supposed to do. If anything feels unusual or concerning, don’t hesitate to reach out to a healthcare provider—they’re there to help.
Your headache will pass. Your protection will last.