YOu could check for the permissions on the infected file and compare them to those used by the scanner that detected the threat (either OAS or ODS).
Also, you could have a detection on read-only media like a CD or DVD.
As said by joe if the VSE found threats in CD/DVD it will deny the access and continue the scan.
but if the threat is not in CD/DVD kindly reboot the infected PC and schedule a on demand scan. and wait for the result.
Sometimes VSE can't gain the necessary control over a file to delete it. Often times after a simple reboot VSE will then grab a hold of the infected file before other processes do and VSE will then be able to delete it. I've seen this happen on numerous occasions. .