diff --git a/agent_based_epidemic_sim/applications/home_work/observer_test.cc b/agent_based_epidemic_sim/applications/home_work/observer_test.cc
index e9357de..fc37ebc 100644
--- a/agent_based_epidemic_sim/applications/home_work/observer_test.cc
+++ b/agent_based_epidemic_sim/applications/home_work/observer_test.cc
@@ -54,7 +54,7 @@ const char* kExpectedHeaders =
     "work_16h,contact_1,contact_2,contact_4,contact_8,contact_16,"
     "contact_32,contact_64,contact_128,contact_256,contact_512\n";
 
-std::unique_ptr<MockAgent> MakeAgent(int64 uuid, HealthState::State state) {
+std::unique_ptr<MockAgent> MakeAgent(int64_t uuid, HealthState::State state) {
   auto agent = absl::make_unique<MockAgent>();
   EXPECT_CALL(*agent, uuid())
       .Times(testing::AnyNumber())
@@ -65,7 +65,7 @@ std::unique_ptr<MockAgent> MakeAgent(int64 uuid, HealthState::State state) {
   return agent;
 }
 
-std::unique_ptr<MockLocation> MakeLocation(int64 uuid) {
+std::unique_ptr<MockLocation> MakeLocation(int64_t uuid) {
   auto location = absl::make_unique<MockLocation>();
   EXPECT_CALL(*location, uuid())
       .Times(testing::AnyNumber())
@@ -86,7 +86,7 @@ TEST(HomeWorkSimulationObserverTest, ZerosReturnedForNoObservations) {
   {
     HomeWorkSimulationObserverFactory observer_factory(
         file.get(),
-        [](int64 uuid) {
+        [](int64_t uuid) {
           return uuid == 0 ? LocationReference::HOUSEHOLD
                            : LocationReference::BUSINESS;
         },
@@ -118,7 +118,7 @@ TEST(HomeWorkSimulationObserverTest, PassthroughFields) {
   {
     HomeWorkSimulationObserverFactory observer_factory(
         file.get(),
-        [](int64 uuid) {
+        [](int64_t uuid) {
           return uuid == 0 ? LocationReference::HOUSEHOLD
                            : LocationReference::BUSINESS;
         },
@@ -148,7 +148,7 @@ TEST(HomeWorkSimulationObserverTest, CorrectValuesForObservations) {
   {
     HomeWorkSimulationObserverFactory observer_factory(
         file.get(),
-        [](int64 uuid) {
+        [](int64_t uuid) {
           return uuid == 0 ? LocationReference::HOUSEHOLD
                            : LocationReference::BUSINESS;
         },
@@ -162,8 +162,8 @@ TEST(HomeWorkSimulationObserverTest, CorrectValuesForObservations) {
     auto work = MakeLocation(1);
 
     std::vector<Visit> home_visits, work_visits;
-    for (int64 i = 0; i < 4; ++i) {
-      int64 uuid = i;
+    for (int64_t i = 0; i < 4; ++i) {
+      int64_t uuid = i;
       home_visits.push_back({
           .location_uuid = 0,
           .agent_uuid = uuid,
@@ -188,8 +188,8 @@ TEST(HomeWorkSimulationObserverTest, CorrectValuesForObservations) {
       observers[0]->Observe(*MakeAgent(uuid, HealthState::SUSCEPTIBLE),
                             outcomes);
     }
-    for (int64 i = 0; i < 3; ++i) {
-      int64 uuid = 4 + i;
+    for (int64_t i = 0; i < 3; ++i) {
+      int64_t uuid = 4 + i;
       home_visits.push_back({
           .location_uuid = 0,
           .agent_uuid = uuid,
@@ -213,8 +213,8 @@ TEST(HomeWorkSimulationObserverTest, CorrectValuesForObservations) {
       }
       observers[0]->Observe(*MakeAgent(uuid, HealthState::EXPOSED), outcomes);
     }
-    for (int64 i = 0; i < 2; ++i) {
-      int64 uuid = 7 + i;
+    for (int64_t i = 0; i < 2; ++i) {
+      int64_t uuid = 7 + i;
       home_visits.push_back({
           .location_uuid = 0,
           .agent_uuid = uuid,
diff --git a/agent_based_epidemic_sim/applications/home_work/risk_score.cc b/agent_based_epidemic_sim/applications/home_work/risk_score.cc
index 4459635..5717b5a 100644
--- a/agent_based_epidemic_sim/applications/home_work/risk_score.cc
+++ b/agent_based_epidemic_sim/applications/home_work/risk_score.cc
@@ -45,8 +45,8 @@ class TogglingRiskScore : public RiskScore {
   void AddExposureNotification(const Exposure& exposure,
                                const ContactReport& notification) override {}
 
-  VisitAdjustment GetVisitAdjustment(const Timestep& timestep,
-                                     const int64 location_uuid) const override {
+  VisitAdjustment GetVisitAdjustment(
+      const Timestep& timestep, const int64_t location_uuid) const override {
     return {
         .frequency_adjustment =
             SkipVisit(timestep, location_uuid) ? 0.0f : 1.0f,
@@ -76,7 +76,7 @@ class TogglingRiskScore : public RiskScore {
   void RequestTest(absl::Time time) override {}
 
  private:
-  bool SkipVisit(const Timestep& timestep, const int64 location_uuid) const {
+  bool SkipVisit(const Timestep& timestep, const int64_t location_uuid) const {
     if (location_type_(location_uuid) != LocationReference::BUSINESS) {
       return false;
     }
diff --git a/agent_based_epidemic_sim/applications/home_work/risk_score_test.cc b/agent_based_epidemic_sim/applications/home_work/risk_score_test.cc
index f9233c0..995f17a 100644
--- a/agent_based_epidemic_sim/applications/home_work/risk_score_test.cc
+++ b/agent_based_epidemic_sim/applications/home_work/risk_score_test.cc
@@ -33,7 +33,7 @@ absl::Time TestDay(int day) {
 std::vector<float> FrequencyAdjustments(
     const ToggleRiskScoreGenerator* const gen, const float essentialness,
     const LocationReference::Type type, const std::vector<int>& days) {
-  int64 location_uuid = type == LocationReference::BUSINESS ? 0 : 1;
+  int64_t location_uuid = type == LocationReference::BUSINESS ? 0 : 1;
   auto risk_score = gen->GetRiskScore(essentialness);
 
   std::vector<float> adjustments;
@@ -75,7 +75,7 @@ TEST(PublicPolicyTest, AppropriateFrequencyAdjustments) {
   DistancingPolicy config =
       BuildPolicy({{10, .6}, {3, .2}, {20, 1.0}, {15, .2}});
   auto generator_or =
-      NewRiskScoreGenerator(config, [](const int64 location_uuid) {
+      NewRiskScoreGenerator(config, [](const int64_t location_uuid) {
         return location_uuid == 0 ? LocationReference::BUSINESS
                                   : LocationReference::HOUSEHOLD;
       });
@@ -112,7 +112,7 @@ TEST(PublicPolicyTest, AppropriateFrequencyAdjustments) {
 TEST(PublicPolicyTest, ZeroStagePolicy) {
   DistancingPolicy config;
   auto generator_or =
-      NewRiskScoreGenerator(config, [](const int64 location_uuid) {
+      NewRiskScoreGenerator(config, [](const int64_t location_uuid) {
         return location_uuid == 0 ? LocationReference::BUSINESS
                                   : LocationReference::HOUSEHOLD;
       });
diff --git a/agent_based_epidemic_sim/applications/home_work/simulation.cc b/agent_based_epidemic_sim/applications/home_work/simulation.cc
index 339b80f..3f9badb 100644
--- a/agent_based_epidemic_sim/applications/home_work/simulation.cc
+++ b/agent_based_epidemic_sim/applications/home_work/simulation.cc
@@ -54,15 +54,15 @@ constexpr char kHouseholdSizeProbability[] = "household_size_probability";
 constexpr char kDistancingStageStart[] = "distancing_stage_start";
 constexpr char kDistancingStageFraction[] =
     "distancing_stage_essential_workers";
-constexpr int64 kPopulationProfileId = 0;
+constexpr int64_t kPopulationProfileId = 0;
 constexpr char kTopBusiness[] = "top_business_size";
 constexpr int kNumTopBusinesses = 5;
 }  // namespace
 
 namespace {
 
-int64 GetLocationUuidForTypeOrDie(const AgentProto& agent,
-                                  const LocationReference::Type type) {
+int64_t GetLocationUuidForTypeOrDie(const AgentProto& agent,
+                                    const LocationReference::Type type) {
   for (const auto& location : agent.locations()) {
     if (location.type() == type) {
       return location.uuid();
@@ -175,7 +175,7 @@ SimulationContext GetSimulationContext(const HomeWorkSimulationConfig& config) {
   LOG(INFO) << "Building agents and locations from config: "
             << config.DebugString();
   // Samples the locations and agents.
-  const int64 kUuidShard = 0LL;
+  const int64_t kUuidShard = 0LL;
   SimulationContext context;
   std::vector<LocationProto>& locations = context.locations;
   auto uuid_generator =
@@ -217,7 +217,7 @@ SimulationContext GetSimulationContext(const HomeWorkSimulationConfig& config) {
   for (int i = 0; i < config.population_size(); ++i) {
     context.agents.push_back(sampler.Next());
   }
-  absl::flat_hash_set<int64> business_uuids;
+  absl::flat_hash_set<int64_t> business_uuids;
   std::for_each(
       context.locations.begin(), context.locations.end(),
       [&business_uuids](const auto& location) {
@@ -226,7 +226,7 @@ SimulationContext GetSimulationContext(const HomeWorkSimulationConfig& config) {
         }
       });
   context.location_type = [business_uuids =
-                               std::move(business_uuids)](int64 uuid) {
+                               std::move(business_uuids)](int64_t uuid) {
     return business_uuids.contains(uuid) ? LocationReference::BUSINESS
                                          : LocationReference::HOUSEHOLD;
   };