A 23-year-old Italian woman was happy to be receiving the Pfizer BioNTech Covid-19 vaccine, but things went south when she was mistakenly given six doses at once at the Noa Hospital.

She reportedly didn’t suffer any aggressive side effects after receiving the overdose.

The woman was kept under observation for 24 hours for any adverse reaction and was later on discharged.

According to hospital spokeswoman Daniella Gianelli, the woman is in “good health” with no underlying conditions.

Gianelli told CNN that a nurse accidentally filled a syringe with an entire bottle of the vaccine, which contained six doses.

She realised her mistake only after the shot was administered to the woman.

Gianelli said the nurse realised her mistake when she saw five empty syringes.

Doctors will continue to monitor the response of the woman’s immune to the “massive dose of vaccine”.

According to CNN, the woman was given the vaccine before other people in her age group as she is an intern in the hospital’s psychology department.

Gianelli said that an internal investigation is underway and added that it was “maybe just human error, definitively not on purpose.”