A woman whose fiance died after having the AstraZeneca coronavirus vaccine is urging people not to be "fobbed off" when reporting side effects.
Former rock singer Zion, 48, of Alston, Cumbria, had an "excruciating" headache eight days after his injection.
Vikki Spit said a paramedic "completely dismissed" any connection, saying it had developed too long after the jab.
The North East Ambulance Service (NEAS) said it could not comment until it had investigated what happened.
Zion's interim fact-of-death certificate lists complications of the vaccine as a possible factor.
An investigation to determine the cause of his death will be conducted by Newcastle's senior coroner Karen Dilks.
Ms Spit, 38, said Zion was healthy and fit and she believes he would have had a good chance of survival if he had received treatment earlier.
"I don't want to scare people off from being vaccinated because I know this is an extremely rare side effect," she said.
"I also know, if it's caught early, the chances of survival are extremely high.
"But, for whatever reason, the paramedic didn't pick up on it.
"So what I want is for all people to be aware, if you have a headache or you have some sort of symptom after having a vaccine, don't be fobbed off."
Zion took painkillers but, after two further days, looked so unwell Ms Spit called an ambulance.
The first responder noted Zion had recently been vaccinated but the paramedic did not think it was relevant, Ms Spit said.
"She was adamant - it's nothing to do with that, it was too long ago - and she diagnosed a migraine," she said.
Zion stayed at home but, when he began to slur his words and had a seizure two days later, Ms Spit called an ambulance again.
"He couldn't speak. At this point, he couldn't put three words together," she said.
Zion was taken to hospital, had surgery, but "didn't wake up".
Reactions 'fully evaluated'
Up to 16 June there were 389 reported cases of blood clots with low platelet levels in people who had the AstraZeneca vaccine in the UK, with 68 deaths.
Of these, 31 cases and four deaths were reported after a second dose.
In the same period there were 12 cases in people given the Pfizer/BioNTech vaccine, with one death, and none in those receiving the Moderna vaccine.
By this date about 16.8m Pfizer/BioNTech, 24.5m AstraZeneca and 0.73m Moderna vaccine first doses had been administered in the UK.
The Medicines and Healthcare Products Regulatory Agency (MHRA) said deaths after suspected adverse drug reactions were "fully evaluated".
"Our detailed and rigorous review into reports of blood clots occurring together with thrombocytopenia is ongoing," a spokesperson said.