Federal health authorities are investigating if the the death of woman is linked to the COVID-19 vaccine after she developed blood clots.

The 48-year-old, who had underlying health issues, died in a Newcastle hospital.

NSW Health has referred the matter to the nation’s medical regulator.

Prime Minister Scott Morrison has warned against rushing to conclusions, saying medical experts should be allowed to investigate first.

More tests are needed to confirm if the vaccine is linked to the death.

Meanwhile, the boss of Pfizer says a third shot of their COVID-19 vaccine may be needed down the track.

The company’s Chief Executive Albert Bourla says it’s likely a booster shot will be necessary within 12-months, and variants will play a key role in whether annual re-vaccination is needed.

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