Dec 16 (Reuters) - Courts have recently blocked many of the Biden administration"s rules and regulations aimed at increasing U.S. vaccination against COVID-19, which has killed more than 800,000 Americans and weighs on economic growth. The vaccine requirements have been challenged by Republican state attorneys general, businesses and religious groups that alleged the administration exceeded its authority. Separately, courts have upheld vaccine requirements imposed by private employers, universities and state and local governments. Below is a look at the various Biden administration vaccine regulations and the status of the legal challenges. WORKPLACE VACCINE OR TESTING RULE The U.S. Department of Labor"s Occupational Safety and Health Administration (OSHA) in November issued a rule requiring all employers with 100 or more employees to ensure their staff are fully vaccinated or produce a negative COVID-19 test once a week and wear a face covering. The requirement, which will apply to over 80 million workers, was blocked in early November by a federal appeals court for the duration of the legal proceedings. The U.S. government is seeking a review of that decision. read more HEALTHCARE VACCINE MANDATE The Centers for Medicare & Medicaid Services (CMS) said in early November it would require COVID-19 vaccinations for workers in most healthcare facilities that receive Medicare or Medicaid reimbursement, from hospitals to home health agencies. This requirement would apply to more than 17 million healthcare workers. A federal judge in Louisiana blocked the rule nationwide when the Dec. 6 deadline arrived for workers to get a first shot. That ruling was later reversed by an appeals court and an injunction against the rule remains in place in 25 states that sued to stop enforcement. read more CMS has not provided an updated vaccination deadline for healthcare providers in the 25 states where the rule has been reinstated. read more CONTRACTOR MANDATE President Joe Biden issued an executive order in September that requires federal contracts to include clauses mandating contractors get their employees vaccinated against COVID-19, which could potentially affect millions of workers. A federal judge in Georgia on Dec. 7 temporarily blocked the administration from enforcing the rule nationwide. read more FEDERAL WORKER MANDATE Biden issued an executive order in September requiring federal employees to get vaccinated by Nov. 22 against COVID-19 to ensure the safety and efficiency of the civil service, and 96.5% of federal workers were considered in compliance. read more At least 17 lawsuits challenged the order but no judge granted a request to temporarily block the rule, generally because they determined the government could mandate a vaccine when acting as an employer.