As of my last knowledge update in September 2021, NASA didn't have immediate plans to leave astronauts Mark Vande Hei and Anton Shkaplerov on the International Space Station (ISS) until next year. Their originally planned return to Earth in early 2022 remained in place, with possible adjustments based on the changing dynamics of space operations.

However, it's essential to note that space missions and schedules are subject to changes due to various factors, such as technical issues, evolving mission objectives, and safety considerations. It's possible that unexpected circumstances could arise, necessitating adjustments to the astronauts' return date.

For the most up-to-date information, I recommend checking the official NASA website or following credible news sources that cover space exploration. This will provide you with the latest and most accurate information on the status of NASA astronauts and their missions.