diff --git a/code/__DEFINES/diseases.dm b/code/__DEFINES/diseases.dm
index 3efea92a646..7fdb3182218 100644
--- a/code/__DEFINES/diseases.dm
+++ b/code/__DEFINES/diseases.dm
@@ -6,6 +6,12 @@
 #define HIDDEN_SCANNER (1<<0)
 #define HIDDEN_PANDEMIC (1<<1)
 
+//Bitfield for Visibility Flags
+DEFINE_BITFIELD(visibility_flags, list(
+	"HIDDEN_FROM_ANALYZER" = HIDDEN_SCANNER,
+	"HIDDEN_FROM_PANDEMIC" = HIDDEN_PANDEMIC,
+))
+
 //Disease Flags
 #define CURABLE (1<<0)
 #define CAN_CARRY (1<<1)
diff --git a/code/datums/diseases/_disease.dm b/code/datums/diseases/_disease.dm
index 6ce52676bf3..9d63a8c21b9 100644
--- a/code/datums/diseases/_disease.dm
+++ b/code/datums/diseases/_disease.dm
@@ -18,7 +18,7 @@
 	/// The probability of this infection advancing a stage every second the cure is not present.
 	var/stage_prob = 2
 	/// How long this infection incubates (non-visible) before revealing itself
-	var/incubation_time = 0
+	var/incubation_time
 
 	//Other
 	var/list/viable_mobtypes = list() //typepaths of viable mobs
diff --git a/code/datums/diseases/advance/advance.dm b/code/datums/diseases/advance/advance.dm
index a9cb1349e80..26a60c8e8a1 100644
--- a/code/datums/diseases/advance/advance.dm
+++ b/code/datums/diseases/advance/advance.dm
@@ -535,11 +535,14 @@
 	return properties["transmittable"]
 
 /**
- *  If the disease has an incubation time (such as event diseases) start the timer
+ *  If the disease has an incubation time (such as event diseases) start the timer, let properties determine if there's no timer set.
  */
 /datum/disease/advance/after_add()
 	. = ..()
 
+	if(isnull(incubation_time))
+		return
+
 	if(incubation_time < world.time)
 		make_visible()
 		return