Varicella

Varicella is an acute viral illness caused by varicella zoster virus (VZV), which the sources identify as the etiologic agent of chickenpox ^[1][2]. VZV is also described as a human-specific neurotropic alpha herpesvirus, and after primary infection it establishes latency in ganglionic neurons ^[2][1]. The provided material does not supply additional source-backed detail on incubation period, lesion evolution, or routine case definitions.

The source material characterizes varicella as potentially severe in immunocompromised individuals, infants, and adults ^[1]. It also situates the wider VZV disease spectrum around later reactivation, which can cause zoster with inflammation, cell death, and persistent radicular pain (postherpetic neuralgia) ^[1]. Other reported zoster complications include myelitis, cranial nerve palsies, meningitis, stroke due to vasculopathy, retinitis, and gastrointestinal involvement such as ulcers, pancreatitis, and hepatitis ^[1]. The review on herpes zoster further notes that manifestations vary across clinical stages and that some manifestations carry a higher risk of complications, but it does not provide varicella-specific symptom detail in the supplied excerpt ^[3].

The provided sources do not give population rates, geographic distribution, or outbreak patterns for varicella itself, so source-backed detail on these topics is not yet available. The material does state that VZV infection is human-specific and that infection does not occur, or is highly restricted, in other species, which has shaped experimental study rather than directly informing field epidemiology ^[2]. One review notes that zoster, the reactivation syndrome caused by the same virus, increases with age and is uncommon in children and young people; this is relevant context for the broader VZV disease burden but is not a direct measure of varicella incidence ^[3].

The provided snippets do not describe the route or exposure mechanism for varicella transmission, so source-backed detail on transmission is not yet available. What is supported is that primary VZV infection can be followed by latency in ganglionic neurons and later reactivation in affected tissues, indicating an important within-host persistence phase ^[1]. Because the evidence boundary does not include transmission passages, no further mechanism should be inferred here ^[1][2].

The supplied sources identify immunocompromised individuals, infants, and adults as groups in whom varicella can be severe ^[1]. For the related reactivation syndrome zoster, advanced age, distress, other infections such as AIDS or COVID-19, and immunosuppression are described as common risk factors, while zoster in children and young people is described as rare and associated with metabolic and neoplastic disorders ^[3]. Source-backed detail on additional varicella-specific risk groups is not yet available in the provided material ^[1][3].

The sources state that highly effective vaccines are available for VZV, and that two vaccines are used: one to prevent varicella and one to prevent zoster ^[1]. A later review also notes that a live attenuated VZV vaccine and a recombinant adjuvanted VZV glycoprotein E subunit vaccine are available for secondary prophylaxis in the zoster context, with the latter described as usable in severely immunosuppressed patients ^[3]. Beyond vaccination, the supplied material does not provide source-backed detail on isolation, post-exposure control, or schedule specifics, so those elements are not yet available from the snippets ^[1][3].

For surveillance purposes, varicella should be read as one expression of VZV infection within a broader disease continuum that includes latent infection and later reactivation as zoster ^[1][2]. The evidence supplied supports recording that the virus can cause clinically severe disease in immunocompromised individuals, infants, and adults, but it does not provide case-finding thresholds, laboratory confirmation criteria, or notification guidance ^[1]. Where monitoring systems also capture zoster, the same etiologic agent should be recognized as capable of producing distinct clinical syndromes across time ^[1][3].

1. 1 Gershon AA et al. Varicella zoster virus infection. Nat Rev Dis Primers. 2015 Jul 2. PMID: 27188665. doi: 10.1038/nrdp.2015.16. PubMed: https://pubmed.ncbi.nlm.nih.gov/27188665/
2. 2 Zerboni L et al. Molecular mechanisms of varicella zoster virus pathogenesis. Nat Rev Microbiol. 2014 Mar. PMID: 24509782. doi: 10.1038/nrmicro3215. PubMed: https://pubmed.ncbi.nlm.nih.gov/24509782/
3. 3 Patil A et al. Herpes zoster: A Review of Clinical Manifestations and Management. Viruses. 2022 Jan 19. PMID: 35215786. doi: 10.3390/v14020192. PubMed: https://pubmed.ncbi.nlm.nih.gov/35215786/
4. 4 Why is Chickenpox Called Chickenpox? Clinical Pediatrics. 1981. doi: 10.1177/000992288102000205. DOI: https://doi.org/10.1177/000992288102000205
5. 5 Varicella‐Zoster Virus (VZV)—Varicella. A Practical Guide to Clinical Virology. 2002. doi: 10.1002/0470857285.ch19. DOI: https://doi.org/10.1002/0470857285.ch19
6. 6 Varicella. SpringerReference. None. doi: 10.1007/springerreference_42857. DOI: https://doi.org/10.1007/springerreference_42857

ICD-10

B01

ICD-11

KA62.0

Total cases

4.1M

Total deaths

1

Peak month

2018-01

Coverage

7 reporting countries · 2000-01-01 → 2026-06-20