Spanish midfielder Isco has played for Real Madrid since 2013. Austrian defender Alaba left Bayern Munich to join Real Madrid on a free transfer in July.
Real Madrid reported last week that a few players and staff had the virus.
The Whites’ Croatian midfielder Luka Modric and Brazilian left-back Marcelo tested positive Wednesday.
Spanish midfielder Marco Asensio, Welsh winger Gareth Bale, Ukrainian goalkeeper Andriy Lunin and Brazilian winger Rodrygo tested positive Thursday.