Health HIstory

 Chickenpox (Varicella) Complete Guide

| Causes, Symptoms, Vaccination, Treatment, and Complications 

1. What is Chickenpox?

Chickenpox is an acute, highly contagious infectious disease caused by the varicella-zoster virus (VZV). It occurs worldwide, mostly in childhood, and is characterized by vesicular rash and fever.

In Korea, 2025 data showed an unusually high number of chickenpox cases by mid-year, indicating a significant increase compared to previous years.

2. Transmission and Surveillance

VZV spreads through respiratory droplets and direct contact with lesions. The incubation period is about 10–21 days. Patients are contagious from 1–2 days before rash onset until all lesions are crusted over.

1) Healthcare Exposure Management

Post-exposure management in healthcare includes vaccination, administration of immune globulin, and proper monitoring for exposed staff.

2) Legal Classification

In South Korea, chickenpox is classified as a notifiable infectious disease, requiring mandatory reporting and national surveillance.

3. Symptoms and Diagnosis

Chickenpox typically presents with low-grade fever, malaise, and itchy vesicular rash. Diagnosis is usually clinical, but PCR or serology can confirm cases when needed.

1) Key Symptoms

Itchy vesicles appear across the body, which progress to pustules, rupture, and then form scabs. These stages occur in crops, giving the classic "dew drop on a rose petal" appearance.

2) Diagnostic Criteria

Clinical diagnosis is standard, supported by laboratory tests such as PCR or antibody assays in atypical cases.

4. Vaccination Information

Vaccination is the most effective prevention. The first dose is recommended at 12 – 15 months, and a second dose at 4–6 years of age.

For unvaccinated adolescents (13 years and older), two doses should be administered 4 – 8 weeks apart.

1) Effectiveness

Varivax and other live-attenuated vaccines provide 70–90% protection against any chickenpox and over 95% protection against severe disease.

2) Side Effects and Contraindications

Most side effects are mild, including injection-site redness or fever. Vaccination is contraindicated in pregnancy and immunocompromised individuals.

5. Treatment Strategies

Mild cases are managed with supportive care (hydration, antipyretics, antihistamines for itching). Antivirals are indicated for high-risk groups such as immunocompromised patients, adults, and pregnant women.

1) Antiviral Use

Acyclovir is effective when started early, reducing symptom severity and disease duration.

6. Complications

Although often mild in children, chickenpox can cause serious complications, especially in adults, pregnant women, and immunocompromised individuals.

1) Major Complications

• Bacterial skin infections
• Pneumonia
• Encephalitis and meningitis
• Hepatitis and sepsis
• Hemorrhagic complications and stroke (rare)

2) Link with Shingles

After recovery, VZV remains dormant in nerve ganglia and may reactivate later in life as herpes zoster (shingles), often causing pain and further complications.

7. Prevention Strategies in 2025

In 2025, global health authorities emphasize universal vaccination coverage. The UK NHS plans to introduce MMRV (measles, mumps, rubella, varicella) combined vaccine in 2026, expected to significantly reduce chickenpox incidence and complications.

Chickenpox is a highly contagious disease, but vaccination and proper management make it preventable and manageable. The 2025 guidelines highlight a combined approach of vaccination, supportive care, and complication prevention as the key to protecting individuals and communities from chickenpox.

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