diff --git a/inst/stan/estimate_infections.stan b/inst/stan/estimate_infections.stan
index cfc07fa7b..2a038bc71 100644
--- a/inst/stan/estimate_infections.stan
+++ b/inst/stan/estimate_infections.stan
@@ -44,17 +44,23 @@ transformed data{
   vector[trunc_max_fixed] trunc_fixed_pmf;
   vector[delay_max_fixed] delay_fixed_pmf;
 
-  gt_fixed_pmf = convolve_ragged_pmf(
-    gt_np_pmf, gt_np_pmf_groups, gt_max_fixed
-  );
+  if (gt_n) {
+    gt_fixed_pmf = convolve_ragged_pmf(
+      gt_np_pmf, gt_np_pmf_groups, gt_max_fixed
+    );
+  }
 
-  trunc_fixed_pmf = convolve_ragged_pmf(
-    trunc_np_pmf, trunc_np_pmf_groups, trunc_max_fixed
-  );
+  if (trunc_n) {
+    trunc_fixed_pmf = convolve_ragged_pmf(
+      trunc_np_pmf, trunc_np_pmf_groups, trunc_max_fixed
+    );
+  }
 
-  delay_fixed_pmf = convolve_ragged_pmf(
-    delay_np_pmf, delay_np_pmf_groups, delay_max_fixed
-  );
+  if (delay_n) {
+    delay_fixed_pmf = convolve_ragged_pmf(
+      delay_np_pmf, delay_np_pmf_groups, delay_max_fixed
+    );
+  }
 }
 
 parameters{
@@ -95,9 +101,11 @@ transformed parameters {
   // Estimate latent infections
   if (estimate_r) {
     // via Rt
-    gt_rev_pmf = combine_pmfs(
-      gt_fixed_pmf, gt_mean, gt_sd, gt_max, gt_dist, gt_max_total, 1, 1
-    );
+    if (gt_n) {
+      gt_rev_pmf = combine_pmfs(
+        gt_fixed_pmf, gt_mean, gt_sd, gt_max, gt_dist, gt_max_total, 1, 1
+      );
+    }
     R = update_Rt(
       ot_h, log_R[estimate_r], noise, breakpoints, bp_effects, stationary
     );
@@ -111,30 +119,34 @@ transformed parameters {
       shifted_cases, noise, fixed, backcalc_prior
     );
   }
-  // convolve from latent infections to mean of observations
-  {
+  if (delay_n) {
+    // convolve from latent infections to mean of observations
     vector[delay_max_total] delay_rev_pmf;
     delay_rev_pmf = combine_pmfs(
       delay_fixed_pmf, delay_mean, delay_sd, delay_max, delay_dist, delay_max_total, 0, 1
     );
     reports = convolve_to_report(infections, delay_rev_pmf, seeding_time);
+  } else {
+    reports = infections[(seeding_time + 1):t];
+  }
+  if (week_effect > 1) {
+    // weekly reporting effect
+    reports = day_of_week_effect(reports, day_of_week, day_of_week_simplex);
+  }
+  if (obs_scale) {
+    // scaling of reported cases by fraction observed
+    reports = scale_obs(reports, frac_obs[1]);
+  }
+  if (trunc_n) {
+    // truncate near time cases to observed reports
+    vector[trunc_max_total] trunc_rev_cmf;
+    trunc_rev_cmf = reverse_mf(cumulative_sum(combine_pmfs(
+      trunc_fixed_pmf, trunc_mean, trunc_sd, trunc_max, trunc_dist, trunc_max_total, 0, 0
+    )));
+    obs_reports = truncate(reports[1:ot], trunc_rev_cmf, 0);
+  } else {
+    obs_reports = reports[1:ot];
   }
- // weekly reporting effect
- if (week_effect > 1) {
-   reports = day_of_week_effect(reports, day_of_week, day_of_week_simplex);
-  }
-  // scaling of reported cases by fraction observed
- if (obs_scale) {
-   reports = scale_obs(reports, frac_obs[1]);
- }
- // truncate near time cases to observed reports
- {
-   vector[trunc_max_total] trunc_rev_cmf;
-   trunc_rev_cmf = reverse_mf(cumulative_sum(combine_pmfs(
-     trunc_fixed_pmf, trunc_mean, trunc_sd, trunc_max, trunc_dist, trunc_max_total, 0, 0
-   )));
-   obs_reports = truncate(reports[1:ot], trunc_rev_cmf, 0);
- }
 }
 
 model {
@@ -144,19 +156,23 @@ model {
       rho[1], alpha[1], eta, ls_meanlog, ls_sdlog, ls_min, ls_max, alpha_sd
     );
   }
-  // penalised priors for delay distributions
-  delays_lp(
-    delay_mean, delay_mean_mean,
-    delay_mean_sd, delay_sd, delay_sd_mean, delay_sd_sd,
-    delay_dist, delay_weight
-  );
-  // priors for truncation
-  delays_lp(
-    trunc_mean, trunc_sd,
-    trunc_mean_mean, trunc_mean_sd,
-    trunc_sd_mean, trunc_sd_sd,
-    trunc_dist, 1
-  );
+  if (delay_n_p) {
+    // penalised priors for delay distributions
+    delays_lp(
+      delay_mean, delay_mean_mean,
+      delay_mean_sd, delay_sd, delay_sd_mean, delay_sd_sd,
+      delay_dist, delay_weight
+    );
+  }
+    // priors for truncation
+  if (trunc_n_p) {
+    delays_lp(
+      trunc_mean, trunc_sd,
+      trunc_mean_mean, trunc_mean_sd,
+      trunc_sd_mean, trunc_sd_sd,
+      trunc_dist, 1
+    );
+  }
   if (estimate_r) {
     // priors on Rt
     rt_lp(
@@ -164,10 +180,12 @@ model {
       seeding_time, r_logmean, r_logsd, prior_infections, prior_growth
     );
     // penalised_prior on generation interval
-    delays_lp(
-      gt_mean, gt_mean_mean, gt_mean_sd, gt_sd, gt_sd_mean, gt_sd_sd, gt_dist,
-      gt_weight
-    );
+    if (gt_n_p) {
+      delays_lp(
+        gt_mean, gt_mean_mean, gt_mean_sd, gt_sd, gt_sd_mean, gt_sd_sd, gt_dist,
+        gt_weight
+      );
+    }
   }
   // prior observation scaling
   if (obs_scale) {