The trial in Switzerland of four former football officials over suspicions that Germany bought votes to obtain the 2006 World Cup was postponed indefinitely on Thursday after one defendant went into self-isolation.
The four were due to face trial in Bellinzona in southern Switzerland.
Swiss ex-FIFA secretary general Urs Linsi, 70, and former German Football Association (DFB) presidents Wolfgang Niersbach, 69, and Theo Zwanziger, 74, and 78-year-old former DFB General Secretary Horst R. Schmidt are facing prosecution.
Linsi, Schmidt and Zwanziger are charged with fraud, while Niersbach is charged with complicity in fraud.
On Wednesday's opening day, only Linsi and Niersbach were present in Bellinzona, the two others having produced medical certificates.
However, on Thursday, Niersbach voluntarily quarantined himself due to coronavirus concerns, Switzerland's ATS national news agency reported.
A suspected case was detected at his stepson's school, said ATS.
The suspects are accused by the Swiss Federal Prosecutor's Office of concealing from the DFB the true destination of a transfer of €6.7 million, paid in 2005 by the organising committee to former Adidas boss, the late Robert Louis-Dreyfus, via FIFA.
All four defendants deny the charges.