Netflix will consider mandating vaccinations for cast and crew on key productions in the U.K., via Deadline. The news comes after multiple productions being halted in the U.K. due to positive COVID-19 cases.

Last week, a multitude of productions were halted or suspended in the U.K. after Zone A production members (crew close to the cast) tested positive for COVID-19. The second season of Netflix’s Bridgerton had to shut down production twice in one week. On Wednesday, Deadline previously reported that Netflix was requiring all American productions to vaccinate their cast and crew as the U.S. goes through a fourth wave of COVID fueled by the Delta variant.

Last week, Hollywood unions agreed that vaccinations would be optional, but other productions in the U.S. have implemented this rule. Netflix will be making this rule standard across the board in U.S. productions. According to Deadline, Netflix will make exceptions to the U.S. rule, but they will be rare and limited to medical, religious, or age reasons as well as for a few shows and movies that are already in production.

There have been calls, however, to make vaccinations standard to all of production, not just Zone A. Sean Penn will reportedly not return to the set of Starz’s Gaslit until all production members are vaccinated.

Netflix will discuss with unions outside of the U.S. to roll out the rule across the board. The streamer will also consider the different vaccination rates in each country. The U.K. has a high vaccination rollout with 37.6 million people now fully vaccinated.

Britain is Netflix’s biggest market outside of America as the streamer spent more than $1 billion on productions last year. If the rule is implemented, this will affect popular series such as Sex Education, The Witcher, and The Crown.