diff --git a/openquake/calculators/views.py b/openquake/calculators/views.py
index <HASH>..<HASH> 100644
--- a/openquake/calculators/views.py
+++ b/openquake/calculators/views.py
@@ -1032,7 +1032,7 @@ def view_delta_loss(token, dstore):
     df = dstore.read_df('agg_loss_table', 'event_id',
                         dict(agg_id=K, loss_id=li))
     if len(df) == 0:  # for instance no fatalities
-        return {}
+        return {'delta': numpy.zeros(1)}
     mod2 = df.index % 2
     losses0 = df['loss'][mod2 == 0]
     losses1 = df['loss'][mod2 == 1]
Fixed view_delta_loss