United Airlines’ vaccine mandate has saved lives.

Before the policy went into effect, an average of one United employee was dying of COVID-19 per week. But since mandating vaccines in the fall, the carrier has not seen a single COVID-19 death among its inoculated employees.

The revelation was made in a memo from the airline’s CEO, Scott Kirby, which was obtained by Business Insider.

Kirby also wrote that no vaccinated employees are currently hospitalized. “In dealing with COVID, zero is the word that matters — zero deaths and zero hospitalizations for vaccinated employees,” Kirby said in the memo. 

“Since our vaccine policy went into effect, the hospitalization rate among our employees has been 100x lower than the general population in the U.S,” he added.

Based on nationwide data “there are approximately 8-10 United employees who are alive today because of our vaccine requirement,” said Kirby.

However, three thousand United workers – about 4% of its workforce – are currently infected with COVID-19, which has contributed to flight delays and cancellations. Kirby said a 1/3 of all workers based at Newark Airport called out sick on a recent day.