Slovakia on Monday became the second EU member after Hungary to start using Russia's Sputnik V vaccine, just two months after Bratislava's purchase of the Covid-19 jabs led to the resignation of Prime Minister Igor Matovic.
At a vaccination centre in the capital Bratislava, some 60 people were due to receive their first dose.
"As this vaccine has been already used in several countries, I see no cause for any concern," Stanislav, 59, told AFP after getting the jab.
Roman, 57, said he had only wanted the Sputnik vaccine.
"I am so firmly convinced of the effectiveness of this vaccine that if Sputnik V had not been available, I would have rather risked dying from the coronavirus," he said.
Sputnik V will initially be rolled out in the Bratislava and Zilina regions and then nationwide.
Only around 5,000 people have registered so far to receive the vaccine, which has not been authorised for use in the EU by the European Medicines Agency (EMA).
The Lancet medical journal published a report in February that found Sputnik V to be over 90 percent effective against symptomatic Covid-19.
It is now used in dozens of countries.
But Sputnik V has sown division among former Eastern Bloc countries, with some seeing it as a godsend and others as a Kremlin propaganda tool.
Slovakia received its first shipment of 200,000 units of the vaccine on March 1. The move proved divisive, with Foreign Minister Ivan Korcok at the time calling them "a hybrid war tool".
Primitive geopolitical hatred
Slovaks between the ages of 18 and 60 can now choose Sputnik from among the available vaccines.
Matovic, who is now the deputy prime minister, has said he wants the upper age limit removed.
"I believe that this time malicious people driven by primitive geopolitical hatred will not be given space for their games and that elderly people will be given the opportunity to be inoculated with the vaccine they want," he said.
Matovic and his health minister Marek Krajci were forced to resign after three members of the four-party ruling coalition opposed the purchase.
A reconstructed government, headed by Eduard Heger, was appointed on April 1.
Since then, the first batch of Sputnik doses has been evaluated by two independent Slovak laboratories, as well as a certified laboratory in Hungary. Samples of the vaccine were also sent back to Russia for evaluation.
The Slovak health ministry approved the vaccine in May.