The policy allowed US authorities to swiftly expel migrants - including asylum seekers - at the border.
Nearly 400,000 people were detained and expelled between its implementation and January 2021, when Mr Trump left the White House.
Even at the height of the pandemic, Title 42 came under frequent criticism from those who argued the policy allowed the US to expel asylum seekers without any legal process.
President Biden promised a more humane approach but his border policy has been sharply criticised too.
www.bbc.com
What Biden did: He defended keeping Title 42 in place, using the pandemic as justification.
Over 2.28 million people were expelled using Title 42 authority between January 2021 and March 2023, the last month for which data is available.
But when the US ended its coronavirus public health emergency on May 11, Title 42 expired with it.