Slovakians still trust the Sputnik V vaccine despite questions about the quality of some of the batches exported from Russia and a lack of data to properly assess it.
In April, Slovakia's drug agency found that some batches manufactured in Russia were sub-standard and could not be used.
Despite this, many Slovaks told Euronews they'd be happy to take it.
"I would choose the Sputnik. I would choose the Russian one - because of the side effects...I heard that AstraZeneca had a lot of side effects. But I haven't really heard anything bad about Sputnik," Barbara Deak, a student in the capital Bratislava said.
A recent study shows 15 percent of Slovaks would opt for the Russian vaccine - a minority but still three times the average for Central and Eastern Europe.
One analyst puts this down to ethnic ties.
"Such positive preference is connected to the positive preference of Russia among Slovaks. 78 percent of Slovaks perceive Russia as their brother nation. Many Slovaks do not perceive Russia as a threat," Katarína Klingová, from the GLOBSEC Policy Institute said.
The Slovak-based think-tank not only asked the population but also studied the online campaigns of all vaccine manufacturers. Their conclusion was controversial: that the Slovak Twitter account of Sputnik is a propaganda machine with the aim of discrediting the Slovak authorities.
Meanwhile, Moscow has accused Slovakia's officials of "sabotage", according to Klingová.
And they've also incorrectly accused the government of breaching the Sputnik acquisition contract, Klingová said.
Prime minister Igor Matović had to resign a month after purchasing the Sputnik vaccine despite the opposition of his coalition partners.
He had allowed Slovakia to enter into a secret deal with Russia to acquire two million doses of it.
But both Slovakia's drugs agency and the EU's European Medicines Agency say Russia has not released enough data to properly assess it properly.
Russia insists Sputnik V is safe and reliable and accuses the West of bias. A tweet from Sputnik last week said EU bureaucrats are "suppressing Sputnik V stellar results".
Only Hungary has allowed its citizens to be inoculated with Sputnik V.
Slovakia says it is now waiting for the results of tests being carried out in Hungary, and only then will it make a decision on whether to use Sputnik V.