Herpes Zoster

Herpes zoster, also known as zoster or shingles, is caused by a virus called varicella zoster virus (VZV). Initial infection with the virus causes chickenpox. After chickenpox resolves the virus continues to resides in certain nerve cells. It may remain latent for many years. It may also re-activate, many years later, and cause shingles which is a painful skin rash. How the virus remains latent in the body is not well understood.


Suggested Citation

Group Health/University of Washington. Group Health and University of Washington. Herpes Zoster. PheKB; 2012 Available from: https://phekb.org/phenotype/112

PubMed References



    The updated pseudo code and data dictionary for the zoster phenotype posted Nov 26, 2012 contain: 1) minor but important modifications to some phenotype criteria and logic, 2) a revised data dictionary that specifies separate tables for subject-level and repeated measures covariate data, 3) revised definitions for some covariate data, and 4) a simplified flow diagram for the phenotype algoritym.

    How should one map the term "continuous enrollment" to a provider of clinical care? The

    pseudocode states, "Has ≥5 years of continuous enrollment (or encounter) history since age 35."

    It would seem that a minimum of 3 month gaps between enounters is a bit too strict to be representative of

    our cohort. Can we change that to maybe yearly or biyearly visits over a minimum of 5 years if using encounters? 


    In non-HMO/integrated care settings "continuous enrollment" may be defined as a history of contiguous 18-month periods with at least one encounter per period.  Thus, 5 years of contiouous enrollment would require encounters in at least 4 contiguous 18-month periods.  This is somewhat arbitrary.  If you feel a more stringent definition (e.g., encounters in contiguous 12-months periods) is more appropriate for your site, please let us know so we can discuss.  We want the criteria to be reasonably consistent across sites, but are aware it is impossible to come up with strictly equivalent criteria across the different care models.

    We will update the pseudocode to reflect this.


    The CPT code Q0081 doesn't seem to be linked to chemotherapy in our EMR. Is anyone else having this issue?




    We discovered that our definition of cancer chemotherapy infusion, used as an exclusion criterion for cases and requested as one of the covariates for both cases and controls, was unnecessarily complicated.  The definition is simplified in this version of the pseudo code, dated Dec. 11, 2012.

    The 23/4/2013 pseudo code is the latest (and likely final) version.  It incorporates a minor change suggested by Geisinger to address false positives (see section 1-2-a).  The data dictionary is also up to date.

    Today (3/7/2013) we provided versions of the pseudocode and data dictionary containing additional descriptions to clarify issues raised by implementing sites.  The logic of the algorithm and definition of data elements has not changed.  There have been no changes to the algorithm or data dictionary since 2/4/2013 and 1/18/2013, respectively.


    Thanks for catching that discrepancy Sarah.  The time frame for nurshing home covariate data is "ever."  This was properly stated in the data definition Excel file's "Zoster_Subject" tab, but incorrectly stated on the "NH-SNF status" tab (where the shorter period was referenced).  I've corrected the data definition Excel file and uploaded a fresh version as of today (3/26/2013).

    The three nursing home related covarites all used "ever" as the time frame.  They are below.




    Nursing_Home_Ever Flag indicating subject has ever been a resident in a nursing home (see worksheet "NH-SNF status" for definition)
    Nursing_Home_First_Age_Yr_Real Subject age in years at first known nursing home admission  (expressed as real number with at least two significant digits to the right o the decimal point) 
    Nursing_Home_Last_Age_Yr_Real Date of last known nursing home admission  (expressed as real number with at least two significant digits to the right o the decimal point)