diff --git a/augur/tasks/github/messages.py b/augur/tasks/github/messages.py
index 86fbe054f..c36abc24a 100644
--- a/augur/tasks/github/messages.py
+++ b/augur/tasks/github/messages.py
@@ -1,5 +1,5 @@
 import logging
-
+from datetime import timedelta, timezone
 
 from augur.tasks.init.celery_app import celery_app as celery
 from augur.tasks.init.celery_app import AugurCoreRepoCollectionTask
@@ -10,12 +10,13 @@
 from augur.tasks.github.util.util import get_owner_repo
 from augur.application.db.models import PullRequest, Message, Issue, PullRequestMessageRef, IssueMessageRef, Contributor, Repo, CollectionStatus
 from augur.application.db import get_engine, get_session
+from augur.application.db.lib import get_core_data_last_collected
 from sqlalchemy.sql import text
 
 platform_id = 1
 
 @celery.task(base=AugurCoreRepoCollectionTask)
-def collect_github_messages(repo_git: str) -> None:
+def collect_github_messages(repo_git: str, full_collection: bool) -> None:
 
     logger = logging.getLogger(collect_github_messages.__name__)
 
@@ -29,9 +30,15 @@ def collect_github_messages(repo_git: str) -> None:
         owner, repo = get_owner_repo(repo_git)
         task_name = f"{owner}/{repo}: Message Task"
 
+        if full_collection:
+            core_data_last_collected = None
+        else:
+            # subtract 2 days to ensure all data is collected 
+            core_data_last_collected = (get_core_data_last_collected(repo_id) - timedelta(days=2)).replace(tzinfo=timezone.utc)
+
         
         if is_repo_small(repo_id):
-            message_data = fast_retrieve_all_pr_and_issue_messages(repo_git, logger, manifest.key_auth, task_name)
+            message_data = fast_retrieve_all_pr_and_issue_messages(repo_git, logger, manifest.key_auth, task_name, core_data_last_collected)
             
             if message_data:
                 process_messages(message_data, task_name, repo_id, logger, augur_db)
@@ -40,7 +47,7 @@ def collect_github_messages(repo_git: str) -> None:
                 logger.info(f"{owner}/{repo} has no messages")
 
         else:
-            process_large_issue_and_pr_message_collection(repo_id, repo_git, logger, manifest.key_auth, task_name, augur_db)
+            process_large_issue_and_pr_message_collection(repo_id, repo_git, logger, manifest.key_auth, task_name, augur_db, core_data_last_collected)
 
 
 def is_repo_small(repo_id):
@@ -51,13 +58,16 @@ def is_repo_small(repo_id):
 
         return result != None
 
-def fast_retrieve_all_pr_and_issue_messages(repo_git: str, logger, key_auth, task_name) -> None:
+def fast_retrieve_all_pr_and_issue_messages(repo_git: str, logger, key_auth, task_name, since) -> None:
 
     owner, repo = get_owner_repo(repo_git)
 
     # url to get issue and pull request comments
     url = f"https://api.github.com/repos/{owner}/{repo}/issues/comments"
 
+    if since:
+        url += f"&since={since.isoformat()}"
+
     # define logger for task
     logger.info(f"Collecting github comments for {owner}/{repo}")
     
@@ -70,7 +80,7 @@ def fast_retrieve_all_pr_and_issue_messages(repo_git: str, logger, key_auth, tas
     return list(github_data_access.paginate_resource(url))
 
 
-def process_large_issue_and_pr_message_collection(repo_id, repo_git: str, logger, key_auth, task_name, augur_db) -> None:
+def process_large_issue_and_pr_message_collection(repo_id, repo_git: str, logger, key_auth, task_name, augur_db, since) -> None:
 
     owner, repo = get_owner_repo(repo_git)
 
@@ -81,11 +91,20 @@ def process_large_issue_and_pr_message_collection(repo_id, repo_git: str, logger
 
     with engine.connect() as connection:
 
-        query = text(f"""
-            (select pr_comments_url from pull_requests WHERE repo_id={repo_id} order by pr_created_at desc)
-            UNION
-            (select comments_url as comment_url from issues WHERE repo_id={repo_id} order by created_at desc);
-        """)
+        if since:
+             query = text(f"""
+                (select pr_comments_url from pull_requests WHERE repo_id={repo_id} AND pr_updated_at > {since} order by pr_created_at desc)
+                UNION
+                (select comments_url as comment_url from issues WHERE repo_id={repo_id} AND updated_at > {since} order by created_at desc);
+            """)
+        else:
+
+            query = text(f"""
+                (select pr_comments_url from pull_requests WHERE repo_id={repo_id} order by pr_created_at desc)
+                UNION
+                (select comments_url as comment_url from issues WHERE repo_id={repo_id} order by created_at desc);
+            """)
+        
 
         result = connection.execute(query).fetchall()
     comment_urls = [x[0] for x in result]
diff --git a/augur/tasks/start_tasks.py b/augur/tasks/start_tasks.py
index ab4cf217c..8aa767ece 100644
--- a/augur/tasks/start_tasks.py
+++ b/augur/tasks/start_tasks.py
@@ -74,7 +74,7 @@ def primary_repo_collect_phase(repo_git, full_collection):
     #Define secondary group that can't run until after primary jobs have finished.
     secondary_repo_jobs = group(
         collect_events.si(repo_git),#*create_grouped_task_load(dataList=first_pass, task=collect_events).tasks,
-        collect_github_messages.si(repo_git), #*create_grouped_task_load(dataList=first_pass,task=collect_github_messages).tasks,
+        collect_github_messages.si(repo_git, full_collection), #*create_grouped_task_load(dataList=first_pass,task=collect_github_messages).tasks,
         collect_github_repo_clones_data.si(repo_git),
     )