diff --git a/templates/frontend/components/footer.tpl b/templates/frontend/components/footer.tpl
index da448f1..ed94e77 100644
--- a/templates/frontend/components/footer.tpl
+++ b/templates/frontend/components/footer.tpl
@@ -33,7 +33,7 @@
 </footer><!-- pkp_structure_footer_wrapper -->
 
 {* Load author biography modals if they exist *}
-{if !empty($smarty.capture.authorBiographyModals|trim)}
+{if !empty($smarty.capture.authorBiographyModals|default:""|trim)}
 	{$smarty.capture.authorBiographyModals}
 {/if}