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  "framework" : "ExposureNotification",
  "identifier" : "/documentation/ExposureNotification/ENExposureConfiguration/infectiousnessForDaysSinceOnsetOfSymptoms",
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  "title" : "infectiousnessForDaysSinceOnsetOfSymptoms"
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# infectiousnessForDaysSinceOnsetOfSymptoms

The mapping between the days since onset of symptoms to the degree of infectiousness.

```
var infectiousnessForDaysSinceOnsetOfSymptoms: [NSNumber : NSNumber]? { get set }
```

## Discussion

> Important:
> This property is available in iOS 12.5, and in iOS 13.7 and later.

The dictionary key is the day since the onset of symptoms. The corresponding value is an [`ENInfectiousness`](/documentation/ExposureNotification/ENInfectiousness) value. When the day is not known, use [`ENDaysSinceOnsetOfSymptomsUnknown`](/documentation/ExposureNotification/ENDaysSinceOnsetOfSymptomsUnknown) as the dictionary key, like this:

```swift
infectiousnessForDaysSinceOnsetOfSymptoms[ENDaysSinceOnsetOfSymptionsUnknown] = 
        infectiousnessHighWeight;
```

You can’t change this property more often than once per week. During development, you can remove this limitation by adding the test entitlement `com.apple.developer.exposure-notification-test` to your project.

> Note:
> You must set this property when using the version 2 scoring algorithm.

---

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