KU Leuven Dismisses Virologist Amid Toxic Leadership Battle

KU Leuven has dismissed Professor Piet Maes, a virologist at the prestigious Rega Institute for Medical Research, following complaints of “far-reaching toxic behavior,” while Belgium’s most famous virologist, Marc Van Ranst, is separately embroiled in a bitter dispute with Maes involving allegations of harassment, sabotage, and theft. The Flemish government’s commissioner has ordered a new external investigation into the toxic climate at the institute, according to reports from VRT NWS and HLN.

The Dismissal

KU Leuven terminated Maes’s contract in February 2026 after an external prevention service (IDEWE) report found evidence of “latent aggressive behavior, pathological lying, monopolizing information, instigating behavior, sabotage, and the creation of a culture of fear,” the university stated. The decision came after failed mediation attempts, with the university saying Maes refused to accept the report’s conclusions and declined an offer of psychological counseling.

Maes, who served as head lecturer and led the department of zoonotic infectious diseases at the Rega Institute, contests the dismissal and is pursuing legal action. He has also filed a €13.7 million claim against the university, alleging it violated a court-imposed communication ban.

A Tale of Two Narratives

The conflict presents two fundamentally different versions of events. According to KU Leuven, Maes was the sole source of toxic behavior at the institute. However, Maes claims he is the victim of a vendetta by Van Ranst and lab manager Elke Wollants, asserting that he was the first to report concerns about their behavior to the vice-rector in late 2023.

“That conversation got completely out of hand. It degenerated into a tirade and threats,” Maes told HLN about a December 2023 meeting with Van Ranst. Van Ranst denies this, stating: “The conversation between me and Piet Maes was calm. That I threatened him is a blatant lie.”

Legal Battles and Questionable Investigations

The case took a significant turn in October 2024 when the Labour Court ruled in Maes’s favor, ordering his suspension lifted. The judge questioned the independence of the IDEWE investigation, noting that KU Leuven had told investigators that Maes was the source of the toxic atmosphere before the investigation began.

“The investigation was conducted from the starting point that Piet Maes is solely guilty of the problems within the Rega Institute,” the court ruling stated, as reported by HLN.

KU Leuven appealed, and in May 2025 the appeals court upheld the decision to lift the suspension, though it did not question the IDEWE report’s validity. The court also criticized KU Leuven for failing to implement a broader action plan to address the toxic climate, which the university only rolled out in July 2025.

Eight of Maes’s direct team members wrote a letter supporting him in September 2024, stating: “It would be incorrect to claim that Professor Maes is perfect, but the assertion that he creates a socially unsafe situation is absolutely not recognized by us as direct team members.” KU Leuven has suggested the signatories were pressured by Maes, a claim he denies.

The €13.7 Million Question

A seizure judge heard Maes’s €13.7 million claim against KU Leuven on April 14, 2026. Maes alleges the university violated a court-ordered communication ban that restricted it from sending messages about his case beyond notifying staff that he could return to work. He claims entitlement to €25,000 per day in penalties. A decision was expected on May 12 but has been postponed.

KU Leuven spokesperson Sigrid Somers contests the claim entirely: “The ban was not generally applicable. It only applied to communication with specific content. That ban was never violated by KU Leuven.”

A New Investigation

The Flemish government’s commissioner for KU Leuven has ordered a new, broader external investigation into the toxic climate at the Rega Institute, following an anonymous report about additional incidents. Van Ranst and Wollants welcome the initiative. “Men may investigate everything down to the bone. We are not afraid of that,” Van Ranst told HLN.

De Morgen reported that KU Leuven confirmed the dismissal, while The Brussels Times noted the broader implications for one of Belgium’s most important research institutions.

What’s Next

The outcome of Maes’s legal challenge to his contract termination and the €13.7 million claim remain pending. The new external investigation ordered by the Flemish government commissioner could shed further light on the toxic dynamics within the Rega Institute. The case raises broader questions about university governance, conflict resolution mechanisms, and the pressures facing elite scientific research institutions in Belgium.