Contact Info
Why You Report All Cases of Varicella
All cases of varicella (chickenpox) are required to be reported to the Minnesota Department of Health (MDH).
On this page:
Why is case-based reporting of varicella important?
What varicella cases should be reported?
What is the clinical presentation of varicella?
Will reported varicella cases be entered into MIIC?
How should cases be reported
Why can't providers rely on laboratories to report varicella cases?
Why is case-based reporting of varicella important?
Case-based reporting of varicella provides the data needed to assess the changing epidemiology of varicella and evaluate the effectiveness of current immunization strategies. It also provides greater opportunity to implement exposure follow-up for high-risk contacts and outbreak control measures.
Which varicella cases should be reported?
- Clinically diagnosed cases (without laboratory confirmation) seen by a provider in a healthcare setting,
- Clinically diagnosed cases based on symptoms relayed by phone to the provider by the patient or parent/guardian, and
- Laboratory-confirmed cases.
Please note that a rash description is required for all cases, especially if laboratory confirmation is not possible or available.
Providers should notify the patient or guardian(s) that MDH or their local public health department will be reaching out to conduct a case investigation.
What is the clinical presentation of varicella?
The CDC case definition for varicella:
In the absence of a more likely alternative diagnosis,
- An acute illness with a generalized rash with vesicles (maculopapulovesicular rash), OR
- An acute illness with a generalized rash without vesicles (maculopapular rash).
This definition was updated January 1, 2024.
Will reported varicella cases be entered into MIIC?
Cases that meet the clinical case definition and are confirmed by laboratory testing will be entered into the Minnesota Immunization Information Connection (MIIC) by MDH staff. This documentation may subsequently be used as evidence of immunity to varicella.
How should cases be reported?
Varicella cases should be reported within one business day so that public health interventions may be implemented in a timely manner. To report a case visit Reporting Varicella (Chickenpox). Please notify the patient/family that MDH or their local public health department will be calling them to conduct a case investigation.
Why can't providers rely on laboratories to report varicella cases?
Provider reporting is needed because:
- Most varicella cases are not laboratory confirmed and only have a clinical diagnosis.
- Laboratory testing does not distinguish varicella (chickenpox) from zoster (shingles).
- Laboratory confirmation may not always be available and false negative results can occur.
- There can be a delay in receipt of laboratory results.
- It is important to report cases that are not laboratory-confirmed to determine the true incidence and current epidemiology of varicella.