Alaska Airlines will require unvaccinated employees to be tested regularly for Covid-19 but the Seattle-based carrier stopped short of mandating vaccines, a policy it said it was considering last month.

Alaska said employees who share proof of vaccination by Oct. 15 will receive a $200 bonus. Three-quarters of the airline’s roughly 20,000 employees are vaccinated so far.

Airline vaccine policies for their staff vary. United Airlines will require its roughly 68,000-person U.S. workforce to be vaccinated by Sept. 27, barring religious and medical exemptions. Delta Air Lines last month announced it plans to impose a $200 surcharge for medical insurance for unvaccinated employees in November.

Alaska Airlines said it will no longer cover the pay of unvaccinated employees for Covid exposure or infection. Unvaccinated staff must also attend “a vaccine education program.”

New hires must be vaccinated to work at Alaska Airlines or subsidiary Horizon Air, also a requirement to begin work at Delta.