By Tom Hals

(Reuters) – A U.S. judge upheld the University of California’s COVID-19 vaccine requirement against a challenge by a professor who alleged he had immunity due to a prior coronavirus infection, in what appears to be the first ruling on the issue.

U.S. District Judge James Selna of Santa Ana, California said that the university system acted in a rational manner to safeguard public health. He mandated the vaccination and did not allow individuals who are immune from infection to be exempted.

Over 43 million Americans have experienced COVID-19. Some critics of vaccinations claim that immunity to an infection makes it unnecessary.

According to the U.S. Centers for Disease Control and Prevention, vaccines are more effective than natural immunity that is weakened over time.

A group of Republican Congressmen wrote Wednesday to the CDC asking them to recognize natural immunity.

According to the lawmakers, natural immunity could be ignored in a rising number of vaccine mandates. This would lead to a lack of workers and possibly even wrongful terminations. The lawmakers warned such mandates could lead to a security crisis, as 20% of military personnel faces separation and many “likely” have natural immunity.

Aaron Kheriaty’s motion to a preliminary injunction was denied by Selna. Selna denied that Professor at University of California Irvine School of Medicine had shown a chance of success. Kheriaty stated however that he will continue litigation.

According to him, he will use the discovery procedure to discover how the policy was formulated. He also plans to interview the university expert witnesses to learn their reasons for rejecting the natural immunity argument.

A request for comment was not received by the university immediately.