Context

A codelist is needed to identify a diagnosis of shingles. This will be used to exclude people temporarily ineligible for the shingles vaccine. This follows Green Book advice "Individuals who have shingles should wait until symptoms have ceased before being considered for shingles vaccination". We currently plan to count anyone with a shingles diagnosis code within last 28 days as ineligible to receive the shingles vaccine.

Inclusion/exclusion criteria

Inclusion:
- Any shingles/herpes zoster related diagnosis code

Exclusion:
- Codes clearly relating to a chickenpox diagnosis - e.g. via naming or synonyms.
- Codes relating to longer term complications following an episode of shingles - e.g. post-herpetic neuralgia.

Borderline cases

• Varicella (38907003) - synonym = chicken pox. OpenCodeCounts usage - 5 million uses - Excluded for consistency as most likely represents chickenpox not shingles. Note large number of uses but these are probably in younger population than our study includes.
• Congenital varicella syndrome (277644009) OpenCodeCounts usage -15 uses - Excluded
• Fetal varicella syndrome (715223009) OpenCodeCounts usage - zero uses - Excluded

Sensitivity vs specificity

This codelist prioritises sensitivity. We want to identify any cases where there is likely a recent shingles infection. A broad codelist of any likely shingles or related codes will be used.