diff --git a/envoy/api/v2/core/health_check.proto b/envoy/api/v2/core/health_check.proto
index 2ad6ed31..b2633d89 100644
--- a/envoy/api/v2/core/health_check.proto
+++ b/envoy/api/v2/core/health_check.proto
@@ -218,6 +218,11 @@ message HealthCheck {
   // Specifies the path to the :ref:`health check event log <arch_overview_health_check_logging>`.
   // If empty, no event log will be written.
   string event_log_path = 17;
+
+  // If set to true, health check failure events will always be logged. If set to false, only the
+  // initial health check failure event will be logged.
+  // The default value is false.
+  bool always_log_health_check_failures = 19;
 }
 
 // Endpoint health status.
diff --git a/envoy/data/core/v2alpha/health_check_event.proto b/envoy/data/core/v2alpha/health_check_event.proto
index e9442cfb..dfb016e8 100644
--- a/envoy/data/core/v2alpha/health_check_event.proto
+++ b/envoy/data/core/v2alpha/health_check_event.proto
@@ -27,6 +27,9 @@ message HealthCheckEvent {
 
     // Host addition.
     HealthCheckAddHealthy add_healthy_event = 5;
+
+    // Host failure.
+    HealthCheckFailure health_check_failure_event = 7;
   }
 
   // Timestamp for event.
@@ -57,3 +60,10 @@ message HealthCheckAddHealthy {
   // is bypassed and the host is immediately added.
   bool first_check = 1;
 }
+
+message HealthCheckFailure {
+  // The type of failure that caused this event.
+  HealthCheckFailureType failure_type = 1 [(validate.rules).enum.defined_only = true];
+  // Whether this event is the result of the first ever health check on a host.
+  bool first_check = 2;
+}