Many people ask how fast ClamAV is in responding to new threats. Here are a few links to reaction time stats for some recent malware:

Sober.P: http://www.pcwelt.de/news/sicherheit/111012/index2.html

Sober.L: http://www.pcwelt.de/news/sicherheit/108562/index.html

Sober.I: http://www.heise.de/security/news/meldung/53427

All of the above statistics were collected by third parties.