diff --git a/DESCRIPTION b/DESCRIPTION
index 8651a06..155c444 100644
--- a/DESCRIPTION
+++ b/DESCRIPTION
@@ -1,7 +1,7 @@
 Package: variantstring
 Type: Package
 Title: Functions for working with variant string format
-Version: 1.8.3
+Version: 1.8.4
 Authors@R: c(
     person("Bob", "Verity", email = "r.verity@imperial.ac.uk", role = c("aut", "cre"))
     )
diff --git a/R/main.R b/R/main.R
index a7400f9..890d62c 100644
--- a/R/main.R
+++ b/R/main.R
@@ -859,12 +859,11 @@ subset_position <- function(position_string, variant_strings) {
   v_unique <- unique(variant_strings)
 
   l_unique <- mapply(function(x) {
-    df_diff <- anti_join(df_position, x, by = c("gene", "pos"))
-    if (nrow(df_diff) == 0) {
-      df_sub <- semi_join(x, df_position, by = c("gene", "pos"))
-      ret <- long_to_variant(list(df_sub))
-    } else {
+    df_join <- inner_join(df_position, x, by = c("gene", "pos"))
+    if (nrow(df_join) == 0) {
       ret <- NA
+    } else {
+      ret <- long_to_variant(list(df_join))
     }
     ret
   }, variant_to_long(v_unique), SIMPLIFY = FALSE) |>
diff --git a/README.Rmd b/README.Rmd
index 73d18d4..b240a12 100644
--- a/README.Rmd
+++ b/README.Rmd
@@ -27,7 +27,7 @@ Tools for working with *variant string format*, a convenient format for encoding
 You can install directly from Github:
 
 ```{r, eval=FALSE}
-devtools::install_github(repo = "mrc-ide/variantstring@v1.8.3")
+devtools::install_github(repo = "mrc-ide/variantstring@v1.8.4")
 ```
 
 Note the use of the @ symbol to reference a specific tagged version. This is highly recommended as the package is still in development and backwards compatibility is not guaranteed.
diff --git a/README.md b/README.md
index 188f424..3c65455 100644
--- a/README.md
+++ b/README.md
@@ -19,7 +19,7 @@ other.
 You can install directly from Github:
 
 ``` r
-devtools::install_github(repo = "mrc-ide/variantstring@v1.8.3")
+devtools::install_github(repo = "mrc-ide/variantstring@v1.8.4")
 ```
 
 Note the use of the @ symbol to reference a specific tagged version.