Madrid(CNN) People in Spain who decline to be vaccinated against coronavirus will be listed in a new register that will be shared with other European Union nations, Spanish Health Minister Salvador Illa has said.
"What will be done is a registry ... of those people who have been offered it and simply rejected it," Illa told Spain's La Sexta TV channel.
Illa said Covid-19 vaccinations would not be made compulsory, and stressed that the information in the register would not be made public, in line with Spain's data protection laws.
But health care professionals have warned that the idea presents potential dangers.
"The most important thing is to know how the registry will be used," said Jose Luis Cobos, deputy direct of the Spanish General Council of Nursing.
"If it's for public health purposes, to better understand COVID, and it's anonymous, that's one thing," he said.
"But if it's 'I'm now on the list of the bad people,' that's another thing. We don't think a registry should be used to infringe on liberties, or for employers against people," he added.
Spain began administering the Pfizer-BioNTech coronavirus vaccine to citizens on Sunday, after it was authorized by European Union regulators last week.
Hours after Illa's television interview on Monday, the head of Spain's Medicines Agency, Maria Jesus Lamas, told Spain's SER radio that the new registry would be used "to understand the causes behind declining the vaccination ... doubt or rejection."
"The registry is anonymous," she added. "There's no chance of identifying anyone in the registry."
Spain's 17 regional governments administer vaccines across the nation.
In the southern region of Andalusia, people currently appear in a registry if they are given a vaccine, including its batch number and who administered, it for quality control purposes, an Andalusia health department spokeswoman told CNN.
The spokeswoman also noted that there is no registry for members of the general public who decline vaccinations, although Andalusia health care workers must sign a document if they refuse a vaccination.
Spain has the world's ninth largest number of coronavirus cases, at more than 1.8 million, and the tenth highest number of deaths, at just over 50,000, according to Johns Hopkins University.