Australian government:
COVID-19 itself poses 8 to 10 times the risk of blood clots (in the brain) than that of COVID-19 vaccines.
https://www.healthdirect.gov.au/thrombosis-with-thrombocytopenia-syndrome-tts
You should seek medical attention immediately if, following vaccination, you have any of these symptoms:
a severe or persistent headache that:
starts at least 4 days after vaccination
doesn’t improve with simple pain-relief medicines such as paracetamol
may be worse when lying down
may be accompanied by nausea and vomiting
blurred vision
difficulty speaking
difficulty breathing
chest pain
drowsiness
seizures
swelling in the leg
persistent abdominal (stomach) pain associated with feeling unwell
tiny blood spots under the skin, away from the site of injection
Common and expected side effects of COVID-19 vaccines include fever, sore muscles, tiredness and headache. These usually start within 24 hours of vaccination and last for 1 to 2 days. These side effects shouldn’t worry you unless they’re severe or persistent.
Suppose natural immunity does happen . . . and lasts a month or two.