diff --git a/code/datums/diseases/_MobProcs.dm b/code/datums/diseases/_MobProcs.dm
index f1793c1cc0..86f26dba9e 100644
--- a/code/datums/diseases/_MobProcs.dm
+++ b/code/datums/diseases/_MobProcs.dm
@@ -79,6 +79,9 @@
 	if(!CanContractDisease(D))
 		return FALSE
 
+	if(species.virus_immune && !global_flag_check(D.virus_modifiers, BYPASSES_IMMUNITY))
+		return FALSE
+
 	var/obj/item/clothing/Cl = null
 	var/passed = TRUE
 
diff --git a/code/datums/diseases/advance/advance.dm b/code/datums/diseases/advance/advance.dm
index 4e57552dab..2bb672a23b 100644
--- a/code/datums/diseases/advance/advance.dm
+++ b/code/datums/diseases/advance/advance.dm
@@ -72,15 +72,11 @@ GLOBAL_LIST_INIT(advance_cures, list(
 	return TRUE
 
 /datum/disease/advance/IsSame(datum/disease/advance/D)
-	if(ispath(D))
-		return FALSE
-
 	if(!istype(D, /datum/disease/advance))
 		return FALSE
 
 	if(GetDiseaseID() != D.GetDiseaseID())
 		return FALSE
-
 	return TRUE
 
 /datum/disease/advance/cure(resistance = TRUE)
@@ -91,14 +87,27 @@ GLOBAL_LIST_INIT(advance_cures, list(
 		remove_virus()
 	qdel(src)
 
-/datum/disease/advance/Copy(process = 0)
-	return new /datum/disease/advance(process, src, 1)
+/datum/disease/advance/Copy()
+	var/datum/disease/advance/A = ..()
+	QDEL_LIST(A.symptoms)
+	for(var/datum/symptom/S as anything in symptoms)
+		A.symptoms += S.Copy()
+	A.disease_flags = disease_flags
+	A.resistance = resistance
+	A.stealth = stealth
+	A.stage_rate = stage_rate
+	A.transmission = transmission
+	A.severity = severity
+	A.speed = speed
+	A.id = id
+	A.Refresh()
+	return A
 
 /datum/disease/advance/proc/Mix(datum/disease/advance/D)
 	if(!(IsSame(D)))
 		var/list/possible_symptoms = shuffle(D.symptoms)
 		for(var/datum/symptom/S in possible_symptoms)
-			AddSymptom(new S.type)
+			AddSymptom(S.Copy())
 
 /datum/disease/advance/proc/HasSymptom(datum/symptom/S)
 	for(var/datum/symptom/symp in symptoms)
@@ -180,12 +189,12 @@ GLOBAL_LIST_INIT(advance_cures, list(
 	var/c2sev
 	var/c3sev
 
-	for(var/datum/symptom/S as() in symptoms)
+	for(var/datum/symptom/S as anything in symptoms)
 		resistance += S.resistance
 		stealth += S.stealth
 		stage_rate += S.stage_speed
 		transmission += S.transmission
-	for(var/datum/symptom/S as() in symptoms)
+	for(var/datum/symptom/S as anything in symptoms)
 		S.severityset(src)
 		switch(S.severity)
 			if(-INFINITY to 0)
@@ -303,7 +312,10 @@ GLOBAL_LIST_INIT(advance_cures, list(
 	if(!id)
 		var/list/L = list()
 		for(var/datum/symptom/S in symptoms)
-			L += S.id
+			if(S.neutered)
+				L += "[S.id]N"
+			else
+				L += S.id
 		L = sortList(L) // Sort the list so it doesn't matter which order the symptoms are in.
 		var/result = jointext(L, ":")
 		id = result
@@ -325,7 +337,7 @@ GLOBAL_LIST_INIT(advance_cures, list(
 	else
 		RemoveSymptom(pick(symptoms))
 		symptoms += S
-	return
+	Refresh()
 
 // Simply removes the symptom.
 /datum/disease/advance/proc/RemoveSymptom(datum/symptom/S)
diff --git a/code/datums/diseases/advance/disease_preset.dm b/code/datums/diseases/advance/disease_preset.dm
index 597d5a5dd5..0478603009 100644
--- a/code/datums/diseases/advance/disease_preset.dm
+++ b/code/datums/diseases/advance/disease_preset.dm
@@ -34,7 +34,6 @@
 	for(var/guaranteed_symptom in guaranteed_symptoms)
 		symptoms += new guaranteed_symptom
 	Finalize()
-	Refresh()
 
 /datum/disease/advance/random/macrophage
 	setsymptom = /datum/symptom/macrophage
diff --git a/code/datums/diseases/advance/symptoms/viral.dm b/code/datums/diseases/advance/symptoms/viral.dm
index 43b00aec53..d8ad1fb2c3 100644
--- a/code/datums/diseases/advance/symptoms/viral.dm
+++ b/code/datums/diseases/advance/symptoms/viral.dm
@@ -77,7 +77,7 @@ BONUS
 	if(!..())
 		return
 	if(!used)
-		for(var/datum/symptom/S as() in A.symptoms)
+		for(var/datum/symptom/S as anything in A.symptoms)
 			if(S == src)
 				return
 			S.power += power
@@ -156,13 +156,13 @@ BONUS
 	if(!..())
 		return
 	if(A.stage >= 5)
-		for(var/datum/symptom/S as() in captives)
+		for(var/datum/symptom/S as anything in captives)
 			S.stopped = FALSE
 			captives -= S
 		if(!LAZYLEN(captives))
 			stopped = TRUE
 	else if(!used)
-		for(var/datum/symptom/S as() in A.symptoms)
+		for(var/datum/symptom/S as anything in A.symptoms)
 			if(S.neutered)
 				continue
 			if(S == src)
diff --git a/code/game/machinery/pandemic.dm b/code/game/machinery/pandemic.dm
index 1a74c040c5..bb0d21993e 100644
--- a/code/game/machinery/pandemic.dm
+++ b/code/game/machinery/pandemic.dm
@@ -226,7 +226,7 @@
 			traits["name"] = disease.name
 			traits["is_adv"] = TRUE
 			traits["symptoms"] = list()
-			for(var/datum/symptom/symptom as() in adv_disease.symptoms)
+			for(var/datum/symptom/symptom as anything in adv_disease.symptoms)
 				traits["symptoms"] += list(symptom.get_symptom_data())
 			traits["resistance"] = adv_disease.resistance
 			traits["stealth"] = adv_disease.stealth
@@ -286,7 +286,6 @@
 /obj/machinery/computer/pandemic/proc/create_culture_bottle(index)
 	var/id = get_virus_id_by_index(text2num(index))
 	var/datum/disease/advance/adv_disease = GLOB.archive_diseases[id]
-	var/old_name = adv_disease.name
 
 	if(!istype(adv_disease))
 		to_chat(usr, span_warning("ERROR: Cannot replicate virus strain."))
@@ -294,7 +293,9 @@
 
 	if(!beaker.reagents.has_reagent(REAGENT_ID_BLOOD, 10))
 		to_chat(usr, span_warning("ERROR: Not enough blood in the sample."))
-		return FALSE
+		return
+
+	var/old_name = adv_disease.name
 
 	use_power(active_power_usage)
 	adv_disease = adv_disease.Copy()