DC Health Alert on Varicella Cluster January 24, 2023

Written by DC Health

On January 9, 2023, DC Health surveillance identified a cluster of varicella (chickenpox) cases among an unvaccinated group of people living in the District of Columbia. As of January 23, 2023, a total of 7 cases have been reported across 4 families. Ages ranged from infant to young adults and all cases have been mild so far without complication.

With the success of varicella vaccination programs in the United States, cases of chickenpox have become far less common. However, people lacking immunity can still catch chickenpox if they are exposed. Immunocompromised people, infants, people aged 15 and older, and pregnant women are at risk for more severe disease and have a higher incidence of complications. The purpose of this email blast is to create a heightened level of awareness and remind providers to consider chickenpox in their differential diagnosis. To ensure timely identification and public health follow-up of cases, the District of Columbia Department of Health (DC Health) asks that providers assist us in our surveillance by doing the following: 1) Review clinical presentations of chickenpox and testing recommendations as needed, and 2) Promptly reporting suspected or confirmed cases to DC Health. Providers should continue providing education on the safety and efficacy of the chickenpox vaccine, and strongly encourage vaccination of eligible patients. Below are some helpful reminders about varicella and instructions on case reporting.


  • The incubation period for varicella is 10 to 21 days, averaging 14 to 16 days after exposure.

Varicella can be spread from person to person by direct contact, inhalation of aerosols from vesicular fluid of skin lesions of acute varicella or zoster, and possibly through aerosolized respiratory secretions.

A person with varicella is contagious beginning one to two days before rash onset until all the skin lesions have crusted.1

  • Review clinical presentations of chickenpox.

Clinical Diagnosis Fact Sheet

More information can be found here.

  • Most diagnoses are made clinically; however, testing is available from most commercial laboratories if needed.

VZV (Varicella Zoster Virus) DNA by PCR (polymerase chain reaction) tests from a clinical specimen, ideally scabs, vesicular fluid, or cells from the base of a lesion is the preferred method for varicella diagnosis. PCR is also useful for confirming breakthrough varicella. Other methods, such as DFA (direct fluorescent antibody test) and culture, are available for diagnosis but are less sensitive and specific than PCR.2

Serology testing can be helpful, especially when identifying past infection, but providers should be aware of its limitations for confirming current infections. More information on testing can be found here.

  • Review current vaccine recommendations, contraindications, and alternatives for those who cannot be vaccinated (e.g., immunoglobulin).

Vaccine Efficacy

Varicella Vaccine Recommendations

Managing People at Risk for Severe Varicella.


Promptly report suspected or confirmed varicella cases to DC Health by emailing doh.epi@dc.gov

Submit a Notifiable Disease and Condition Case Report Form online using DCRC: dccovid.force.com/provider/s/login.

For more information, or to report suspected varicella cases, please contact the

Division of Epidemiology – Disease Surveillance and Investigation:

Phone: 1-844-493-2652 | Fax: (202) 442-8060 | Email: doh.epi@dc.gov