The main vaccination center in Peristeri, western Athens was placed in emergency mode on Friday after unknown assailants cut the wiring of the generator for the refrigerators, placing thousands of vaccines at risk.
The alert was raised amid fears of possible power outages due to the fires that continued to rage across northern Attica.
The generators were supposed to activate in case of such power failures.
An inspection revealed that four cables, measuring 4 meters in length and 2.5 centimeters in diameter, that connected the generator to the center had been cut.
The incident was reported to the police, who were investigating whether the incident was linked to thieves who steal cables for their copper content or a case of sabotage, possibly by anti-vaxxers.