Workers at a subsidiary of Activision Blizzard voted to unionize on Monday, establishing the first union at a large US video game publisher.

Software quality assurance workers at Activision's Raven Software division, which works on the "Call of Duty" series, voted 19 to 3 in favor of unionization and will be represented by the Communications Workers of America (CWA).

The vote, counted by the National Labor Relations Board (NLRB), applies to a segment of workers at Raven, which employs around 350 people. The NLRB previously rejected Activision's demand that a union election include all workers.

This week's vote is the latest in a string of unionization efforts that have been under way at other technology firms in recent months, including retail workers at Apple stores and Amazon warehouse workers.  Technology staff have also unionized at organizations, such as "The New York Times," where staff voted 404 to 88 in favor of creating a union that represents around 600 software engineers, data analysts and other workers.

The decision to unionize at raven Software follows months of organizing by Raven workers. The organizers formed the Game Workers Alliance in January to represent workers following a five-week strike over Activision's decision to lay off 12 quality assurance testers. The Game Workers Alliance action was backed by the CWA.

"Our biggest hope is that our union serves as inspiration for the growing movement of workers organizing at video game studios to create better games and build workplaces that reflect our values and empower all of us," workers in the union at Activision said in a statement. "We look forward to working with management to positively shape our working conditions and the future of Activision Blizzard through a strong union contract."

The company, in a statement, reiterated that wanted any union vote to be conducted among all of its workers: "We respect and believe in the right of all employees to decide whether or not to support or vote for a union. We believe that an important decision that will impact the entire Raven Software studio of roughly 350 people should not be made by 19 Raven employees."

Activision is set to be acquired by Microsoft in a$68.7 billion deal that was approved by Activision shareholders in April. The acquisition is set to close by June 2023.