
You May Have a Severe Headache

You may have a headache, and it will be "severe"—these may "range from cluster headache such as onset, worst headache of life, migraine-like headache, exploding headache, chronic tension headache, chronic daily headache, and thunderclap headache," according to one study.
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You May Have New Neurological Symptoms

"If you have cerebral venous sinus thrombosis: Respond quickly to symptoms like headaches, blurry vision, fainting, losing control of a part of your body, and seizures. If you have the above symptoms, have someone take you immediately to the emergency room or call 911 for help," says Johns Hopkins.
You May Have Severe Abdominal Pain

One Cerebral Venous Sinus Thrombosis patient—unrelated to the vaccines—had a "mood disorder, infrequent migraine without aura, GERD, and ulcerative colitis presented to the emergency department with four weeks of abdominal pain, hematochezia, and an unintentional 28-pound weight loss over those four weeks."
You May Have Leg Swelling

"If a blood clot forms in a deep vein, it can block the flow of blood, which prevents the tissues from draining properly. This causes excess fluid accumulation, swelling, warmth and discomfort in the leg. A blood clot in a deep vein may also break off and travel back to the heart and into the lungs," says Lifebridge Health.
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You May Have Tiny Red Spots on the Skin (Petechiae)

"Petechiae are pinpoint, round spots that appear on the skin as a result of bleeding. The bleeding causes the petechiae to appear red, brown or purple. Petechiae (puh-TEE-kee-ee) commonly appear in clusters and may look like a rash. Usually flat to the touch, petechiae don't lose color when you press on them," says the Mayo Clinic. This issue "may start as ischemic neuronal damage, petechiae later merging into large hematomas," says a study.
You May Have New or Easy Bruising

"Easy bruising sometimes indicates a serious underlying condition, such as a blood-clotting problem or a blood disease," says the Mayo Clinic. "See your doctor if you:
- Have frequent, large bruises, especially if your bruises appear on your trunk, back or face, or seem to develop for no known reasons
- Have easy bruising and a history of significant bleeding, such as during a surgical procedure
- Suddenly begin bruising, especially if you recently started a new medication
- Have a family history of easy bruising or bleeding"
You May Have Shortness of Breath

Shortness of breath " typically appears suddenly and always gets worse with exertion," says the Mayo Clinic. It can also include difficulty breathing.
You May Have a Backache

The CDC is recommending doctors look out for "severe headache, backache, new neurologic symptoms, severe abdominal pain, shortness of breath, leg swelling, petechiae (tiny red spots on the skin), or new or easy bruising" and urges they "obtain platelet counts and screen for evidence of immune thrombotic thrombocytopenia."
What to Do if You Experience These Symptoms

If you experience any of them, "contact your healthcare provider and seek medical treatment urgently."
The risk of developing the condition is higher in the first three weeks after getting the vaccine and decreases over time. "If you received the vaccine more than three weeks ago, the risk of developing a blood clot is likely very low at this time," they explain. "If you received the vaccine within the last three weeks, your risk of developing a blood clot is also very low and that risk will decrease over time." So get vaccinated when it becomes available to you, and to protect your life and the lives of others, don't visit any of these 35 Places You're Most Likely to Catch COVID.