In its decision 9C_281/2024 of 28 July 2025, the Federal Supreme Court has partially upheld the appeal filed by A regarding the cost coverage for hyperbaric oxygen therapy to treat the effects of post-Covid-19 illness by CSS Kranken-Versicherung AG (CSS).

The Federal Supreme Court held that hyperbaric oxygen therapy was listed in annex 1 to the Health Insurance Benefits Ordinance (Krankpflege-Leistungsverordnung, KLV), but its use for post-Covid-19 illnesses was not explicitly mentioned. However, since annex 1 to the KLV also contained a list of excluded fields of application, it could not be assumed that the omission of the mention of the medication in the list of application would constitute a qualified silence. Therefore, annex 1 to the KLV contained no information – neither negative nor positive – regarding the obligation by the insurance to cover the costs.

Regarding the effectiveness of hyperbaric oxygen therapy, the court held that several studies confirmed the positive effects of the treatment. The cantonal court had violated its obligation to investigate by not considering the publicly available studies proving the effectiveness and long-term effects of the therapy.

As a result, the Federal Supreme Court referred the case back to CSS to issue a new decision.

For more information, see here.