People with Down's syndrome, sickle cell disease and kidney transplant patients are most at risk of dying from the coronavirus after having two vaccines, experts have found.
Findings from a tool developed by UK researchers concluded that those with certain conditions are up to 12 times more likely to be hospitalised or die from the virus after being jabbed, compared to healthy people.
And the likelihood of hospitalisation and dying from Covid also increased as people got older, while men and those of Indian and Pakistani origin were at higher risk.
A person's overall risk from severe health outcomes after being double-jabbed is still very small, with the vaccines having already tens of thousands of lives.
But the study confirms that those who were already at-risk before being vaccinated are still more likely to be hospitalised or die if they catch it, compared to healthy double-jabbed people.
Researchers said the calculator can help the Government make policy decisions, such as who should be given additional Covid vaccines.
And medics can use it to make clinical decisions, such as which patients should receive the new monoclonal antibody treatment.