The US Supreme Court has blocked a proposal from the Biden administration that would have required workers at firms with more than 100 employees to be vaccinated.

Those that were not vaccinated would have been required to take a weekly COVID-19 test at their own expense.

The judges described the measure, which affects 84 million workers, as “a blunt instrument”.

“It draws no distinctions based on industry or risk of exposure to COVID–19,” they said.

Business opposition

The judgment said that the Occupational Safety and Health Administration (OSHA), which was charged with enforcing the measure, had “never before adopted a broad public-health regulation of this kind – addressing a threat that is untethered, in any causal sense, from the workplace”.

In a brief submitted to the court on behalf of the Biden administration, Solicitor General Elizabeth Prelogar had argued that the measures were necessary "confronted with the deadliest pandemic in the nation's history".

A group of 26 business associations opposed to the mandates, however, had said that they would "inflict irreparable harm upon hundreds of thousands of businesses".

The court backed a second vaccine mandate that applies to employees of federal health-care providers that receive federal funding.