A recent evaluation of more than 250 antivirus apps in the Google Play Store found that 70% of them were so worthless as to fail to meet even the most basic standards. AV Comparatives found that many of the apps were based on old code, or used some kind of list of known sites and could not detect even 30% of the malware thrown at them.
Google Play has taken steps to remove bad actors from the Play Store, but obviously still has much work to be done. Some of the apps AV Comparatives evaluated were actually considered to be risky, some failing to detect a single malware sample. Some of the worst were paid or subscription apps.
The good news is that there are apps, many of them from names you know, that detected 100% of the malware samples. You can read the entire list here.
Ken Charvoz 