In a bid to get as many citizens as possible vaccinated, Romania's forbidding Bran Castle, widely known as the inspiration for the lair of Dracula, offers its visitors a COVID-19 jab for a certificate and free tour.

"I came to visit the castle with my family and when I saw the poster I gathered up my courage and agreed to get the injection," said 39-year-old engineer Liviu Necula.

Those who take the jab are handed a certificate hailing their "boldness and responsibility" promising they will be welcome at the castle "for the coming 100 years" – as well as offered a free tour of the "torture chamber."

Nestled in a misty valley in the Carpathian mountains, Bran Castle is associated with the 15th-century Romanian prince Vlad Tepes, known as "the Impaler," although he never stayed there.

Dracula author Bram Stoker is believed to have been inspired by Vlad and descriptions of Bran Castle when writing his 1897 novel that helped found the modern vampire genre.

Romania's government has turned to local vaccination drives and 24-hour "marathons" at major venues like the National Library in Bucharest to get as many citizens as possible immunized.

"These centers are for everyone who wants to get vaccinated but doesn't feel like making an appointment online," Marius Nasta hospital director Beatrice Mahler told AFP.

But she added that it would still be difficult to reach people living in the many areas without local doctors.

Almost 3.6 million Romanians of the country's 19 million people have received at least one vaccine dose, with authorities aiming for 5 million by June, while the country was struck by protests against the coronavirus curfew last month.