diff --git a/augur/sequence_traits.py b/augur/sequence_traits.py
index 347c32b7a..d030d0747 100644
--- a/augur/sequence_traits.py
+++ b/augur/sequence_traits.py
@@ -3,7 +3,6 @@
 """
 
 import sys
-import gzip
 import numpy as np
 from treetime.vcf_utils import read_vcf
 from collections import defaultdict