diff --git a/cara/apps/expert.py b/cara/apps/expert.py
index 261afe75..bba12b6b 100644
--- a/cara/apps/expert.py
+++ b/cara/apps/expert.py
@@ -153,16 +153,16 @@ class ExposureModelResult(View):
 
     def update_textual_result(self, model: models.ExposureModel):
         lines = []
-        P = model.infection_probability()
+        P = np.array(model.infection_probability()).mean()
         lines.append(f'Emission rate (virus/hr): {np.round(model.concentration_model.infected.emission_rate_when_present(),0)}')
         lines.append(f'Probability of infection: {np.round(P, 0)}%')
 
         lines.append(f'Number of exposed: {model.exposed.number}')
 
-        new_cases = np.round(model.expected_new_cases(), 1)
+        new_cases = np.round(np.array(model.expected_new_cases()).mean(), 1)
         lines.append(f'Number of expected new cases: {new_cases}')
 
-        R0 = np.round(model.reproduction_number(), 1)
+        R0 = np.round(np.array(model.reproduction_number()).mean(), 1)
         lines.append(f'Reproduction number (R0): {R0}')
 
         self.html_output.value = '<br>\n'.join(lines)
diff --git a/cara/models.py b/cara/models.py
index d98baf02..d09f9f69 100644
--- a/cara/models.py
+++ b/cara/models.py
@@ -459,13 +459,10 @@ class SARSCoV2(Virus):
         piecewise constant model (for more details see A. Henriques et al,
         CERN-OPEN-2021-004, DOI: 10.17181/CERN.1GDQ.5Y75)
         """
-        halflife = np.empty_like(humidity)
-        # Taken from Morris et al (https://doi.org/10.7554/eLife.65902) data at T = 22°C and RH = 40 %.
-        halflife[humidity <= 0.4] = 6.43
-        # Taken from Doremalen et al (https://www.nejm.org/doi/10.1056/NEJMc2004973).
-        halflife[humidity > 0.4] = 1.1
-        return halflife
-
+        # Taken from Morris et al (https://doi.org/10.7554/eLife.65902) data at T = 22°C and RH = 40 %,
+        # and from Doremalen et al (https://www.nejm.org/doi/10.1056/NEJMc2004973).
+        return np.piecewise(humidity, [humidity <= 0.4, humidity > 0.4], [6.43, 1.1])
+        
 
 Virus.types = {
     'SARS_CoV_2': SARSCoV2(
diff --git a/setup.py b/setup.py
index e057da5c..e8136836 100644
--- a/setup.py
+++ b/setup.py
@@ -27,7 +27,7 @@ REQUIREMENTS: dict = {
         'matplotlib',
         'memoization',
         'mistune',
-        'numpy != 1.22.0',
+        'numpy',
         'psutil',
         'python-dateutil',
         'scipy',