Araceli Rosario, a care center resident in the city of Guadalajara, told reporters that she had felt "nothing, just a slight sting" from the Pfizer-BioNTech vaccine.
The lady encouraged everyone to follow her example. She and the other first batch of recipients will have a second dose in 21 days.
Monica Tapias, who worked for the same care center, said she was proud to be the second person inoculated.
Tapias expressed regret that the vaccine "couldn't arrive in time" for many others who have deceased. "I hope we can finish with this illness now," she added.
Spain is set to allocate 350,000 doses of the COVID-19 vaccine each of the following 12 weeks to cover around 2.9 million care home residents, healthcare workers and dependent elderly people who live outside of the institutions.
Health Minister Salvador Illa said that it is hoped that up to 25 million people will have been vaccinated by the summer.
As of Sunday, Spain has reported a total of 1,854,951 COVID-19 cases and 49,824 related deaths, according to its Health Ministry.
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