diff --git a/code/datums/diseases/advance/advance.dm b/code/datums/diseases/advance/advance.dm
index 3d8bfdf8837..57ce722cd64 100644
--- a/code/datums/diseases/advance/advance.dm
+++ b/code/datums/diseases/advance/advance.dm
@@ -405,7 +405,7 @@
 /datum/disease/advance/proc/AddSymptom(datum/symptom/S)
 	if(HasSymptom(S))
 		return
-	while(get_symptom_weights() > VIRUS_SYMPTOM_LIMIT + S.weight)
+	while(get_symptom_weights() + S.weight > VIRUS_SYMPTOM_LIMIT)
 		RemoveSymptom(pick(symptoms))
 	symptoms += S
 	S.OnAdd(src)