United Airlines says more than 97% of its U.S.-based employees are fully vaccinated against COVID-19 now that there is less than a week before a deadline to get the shots or get fired.

The airline said Wednesday that the new figure does not include a "small number" of employees who are seeking a medical or religious exemption from vaccination.

"Vaccine requirements work," United said in a memo to employees.

The airline said last month that up to 90% of pilots and nearly 80% of flight attendants were vaccinated, but it did not give a companywide figure at the time.

United said it will start termination proceedings against unvaccinated employees as soon as next Tuesday.

The airline is among a small group of companies that announced they would require vaccinations even before Sept. 9, when President Joe Biden issued an executive order directing employers with more than 100 workers to require vaccinations or weekly testing for the virus.

Last month, United set a deadline of Sept. 27 – next Monday -- for its 67,000 U.S.-based employees to get vaccinated or face termination. However, employees who apply unsuccessfully for an exemption could get more time. They will have five weeks after their denial to get vaccinated.

Chicago-based United declined to give a precise figure for how many workers have asked for an exemption and whether any requests have been granted.

Employees who win an exemption will be placed on leave beginning Oct. 2. Some could come back if they wear masks and are tested weekly, although the timing of their return is uncertain.