The programme has indirectly helped currencies and government bonds in the European Union's eastern members, too.
The ECB said it would extend the purchases beyond December by nine months but cut the monthly amount it buys from 60 billion euros to 30 billion euros.
Analysts' consensus forecast had been a cut to 40 billion euros. Central European currencies and bonds eased ahead of the meeting due to fears of a shift towards hawkish policies.
The cut was deeper than expected but the comments from ECB chief Mario Draghi did not justify the concerns. He said a substantial degree of monetary accommodation was still needed, and core inflation was yet to show convincing signs of rising.
"He kept the back door open. His comments were not very hawkish," one Budapest-based currency dealer said.
The forint, which has been weakened in past months by the Hungarian central bank's liquidity-boosting policies, regained some ground to hold steady on the day at 319.34 against the euro at 1352 GMT.
The zloty firmed 0.15 percent to 4.2365.
At the bond auctions Hungary held on Thursday, 10-year papers were sold at an average yield of 2.46 percent, down 2 basis points from secondary market levels in early trade.
The ECB comments helped the yield drop further after the auction, which drew "good, but not aggressive demand", in the market to 2.44 percent, tracking a decline in the corresponding Bund yield, one Budapest-based fixed income trader said.
Some Czech and Polish bond yields also dropped.
The Czech crown rebounded and hit a 4-year high at 25.55 versus the euro.
It has been strengthening since mid-September, supported by hawkish comments from Czech central bank (CNB) rate setters.
Recent comments from Vice-Governor Mojmir Hampl and rate setter Tomas Nidetzky underpinned expectations that the CNB will continue to increase its interest rates at its meeting on Nov. 2, and will indicate that more tightening will come.
The crown's strengthening can continue, market participants said.
"It seems the CNB is still counting on the overboughtness of the crown and therefore it won't have to constrain its policy tightening with regards to the cautious ECB," CSOB analysts said in a note.
Equities were mostly rangebound in the region.
The key exception was Polish refiner Lotos which gained 6 percent after reporting 63 percent surge in third-quarter net profit.