The two men allegedly threw Molotov cocktails at the facility last month, causing fire damage.
Italian police have arrested two anti-vaxxers for throwing firebombs at a COVID-19 vaccination centre in Brescia.
Two "Molotov cocktails" were thrown at the vaccination centre in the northern Italian city on 3 April, setting fire to the side of two pavilions.
Two suspects, aged 51 and 52, have been detained on terrorism offences, Italy's military police said in a statement.
They have been arrested on suspicion of possessing and using explosive devices and "weapons of war", the Carabinieri added.
Images published by the authorities showed significant burns to the side of the centre, where COVID-19 vaccines were stored. No one was injured in the incident.
While the side of the centre was damaged, the fire did not spread to threaten the unit’s electrical supply.
Police the two men arrested were members of the anti-vaccination "No Vax" movement and had tried to sabotage vaccination efforts to "feed the climate of uncertainty".
Shortly ahead of the arson attack, one had allegedly written on Facebook; "there are no other solutions."
"If we want to destroy the enemy we must use the same weapon ‘fear’ and their fear is our unity," he wrote, according to ANSA. Their post and accounts now appear to have been removed from Facebook.
Both suspects are from Brescia in Lombardy, Italy's worst affected region since the start of the pandemic and were arrested after an extensive investigation using surveillance cameras and telephone interceptions.
Police have also carried out searches at addresses in Brescia and Verona, linked to the same anti-vaxx movement.
In March, a COVID-19 testing facility in the Dutch town of Bovenkarpsel was also damaged after an explosion caused by a "small metal object or pipe".