diff --git a/envoy/data/core/v2alpha/health_check_event.proto b/envoy/data/core/v2alpha/health_check_event.proto
index 51efb119..29a625f8 100644
--- a/envoy/data/core/v2alpha/health_check_event.proto
+++ b/envoy/data/core/v2alpha/health_check_event.proto
@@ -32,6 +32,12 @@ message HealthCheckEvent {
 
     // Host failure.
     HealthCheckFailure health_check_failure_event = 7;
+
+    // Healthy host became degraded.
+    DegradedHealthyHost degraded_healthy_host = 8;
+
+    // A degraded host returned to being healthy.
+    NoLongerDegradedHost no_longer_degraded_host = 9;
   }
 
   // Timestamp for event.
@@ -69,3 +75,9 @@ message HealthCheckFailure {
   // Whether this event is the result of the first ever health check on a host.
   bool first_check = 2;
 }
+
+message DegradedHealthyHost {
+}
+
+message NoLongerDegradedHost {
+}