Production of movies and TV shows is getting disrupted again because of Covid-19 and uncertainty over vaccination protocols, a setback as networks and streaming services remain hungry for fresh content.

Among shows that recently suspended shooting as members of the production tested positive for Covid-19 is “House of the Dragon,” the much-anticipated prequel to HBO’s smash hit “Game of Thrones.” Hulu’s comedy “Woke” also had to stop filming because of positive Covid-19 cases.

Both shows have resumed production.

Movie projects that have been suspended include “God Is a Bullet,” starring Jamie Foxx and Nikolaj Coster-Waldau. The production, which is filming in Mexico, shut down this week after actors who had been vaccinated tested positive for Covid-19. Recently production on Tom Cruise’s “Mission: Impossible 7” film shut down briefly because of positive tests.

Shows that temporarily stopped shooting include the ‘Game of Thrones’ prequel, ‘House of the Dragon,’ with Emma D'Arcy and Matt Smith.

Shows that temporarily stopped shooting include the ‘Game of Thrones’ prequel, ‘House of the Dragon,’ with Emma D'Arcy and Matt Smith.

Photo: Ollie Upton/HBO

The challenges facing Hollywood echo those seen throughout corporate America as a surge due in large part to the highly infectious Delta variant and current vaccination rates raise questions about the ideal timetable and practices for returns to workplaces.

Hollywood movie and TV sets differ from typical office environments as people are often forced to work in close proximity with one another. Masks and social distancing are sometimes unrealistic, and cast and crew members frequently enter and leave filming locations.

Film and television production experienced a significant rebound during the first four months of 2021, leading the industry to hope that the worst of the pandemic disruptions were behind it. Through April of this year, production approached levels similar to pre-pandemic output as performers’ combined earnings hit a new high compared with previous years, according to the Screen Actors Guild-American Federation of Television and Radio Artists.

Production delays could again imperil the ability of networks and streaming services to keep their content pipelines flowing. Netflix Inc. has cited a decline in fresh content as one of the causes for its slowdown in subscriber growth.

The fast-spreading Delta variant is driving up Covid-19 cases, and vaccination rates are stalling. The Centers for Disease Control and Prevention this week advocated a return to indoor masking in much of the country, a step already taken by Los Angeles County.

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Several movie and TV studio executives and talent agents said there has been an increase in the number of productions pausing because of positive Covid-19 tests. The rise in cases and disruptions come as debates over vaccination protocols are heating up.

Studios and unions decided earlier this month that if an individual production wants to require vaccinations for those who work in proximity to the actors on a set, they will support the measure. As a group, they didn’t go farther with dictates.

On Wednesday, Netflix told its producers that it would require everyone working in close contact with actors on U.S. productions to be vaccinated, a company spokesman confirmed.

The key area on a set is known as “Zone A,” where the actors and key crew members operate during filming. Actors working on a set aren’t typically masked there.

Concern about vaccinations isn’t limited to Zone A, however. A studio executive said he recently received a call from an agent whose actor client wanted a new driver to the set because the driver wasn’t vaccinated.

There has been some talk between the studios and unions on how to distinguish between the vaccinated and unvaccinated on sets, according to executives and agents. There is concern, though, that a “Scarlet Letter” atmosphere will result, one person said.

That doesn’t mean those who aren’t vaccinated get a pass from colleagues.

Last week actor Sean Penn said he wouldn’t return to the production of a limited series on the Watergate scandal called “Gaslit” that is being made for the pay-TV channel Starz unless all of the cast and crew agreed to be vaccinated.

Since Mr. Penn’s statement, several actors and crew members have been vaccinated, people familiar with the matter said.

Studio executives and talent agents said they expect more actors to be vocal about having everyone on set vaccinated, particularly those who work in proximity to talent.

“For people who don’t have a legitimate religious or medical reason for exemption, they’re simply going to have to make a decision for themselves whether they wish to work for that employer who has a mandatory vaccination policy,” said Duncan Crabtree-Ireland, national executive director of SAG-AFTRA.

Write to Joe Flint at joe.flint@wsj.com and R.T. Watson at rt.watson@wsj.com