Shingles Development and Reactivation

Pathophysiologic Mechanism

The varicella-zoster virus (VZV) reactivates due to declining cell-mediated immunity, leading to shingles development, according to the American Academy of Pediatrics 3 and the Journal of Microbiology, Immunology and Infection 1, 2
Approximately 95-99% of adults have been infected with VZV and harbor latent virus capable of reactivation, as reported by the American Academy of Pediatrics 3
The critical factor in shingles development is declining cell-mediated immunity to VZV, which normally keeps the latent virus suppressed, as stated by the Journal of Microbiology, Immunology and Infection 1, 2

Advancing age is the most significant risk factor, with incidence rising sharply after age 50 due to natural waning of VZV-specific cellular immunity, according to the American Academy of Pediatrics 3
Patients with conditions like rheumatoid arthritis, systemic lupus erythematosus, diabetes mellitus, and inflammatory bowel disease have elevated risk (risk ratios ranging from 1.23 to 2.08), as reported by the Journal of Microbiology, Immunology and Infection 2
Recent evidence identifies COVID-19 as an associated factor in shingles reactivation, as stated by the Journal of Microbiology, Immunology and Infection 2

The reactivated virus spreads along the sensory nerve to the skin area (dermatome) innervated by that specific nerve root, producing the characteristic unilateral, dermatomal vesicular rash with associated pain, as described by the Journal of Microbiology, Immunology and Infection 1 and the Centers for Disease Control and Prevention (MMWR Recommendations and Reports) 4
Burning pain typically precedes the rash by several days (24-72 hours in most cases), as reported by the Centers for Disease Control and Prevention (MMWR Recommendations and Reports) 4 and Praxis Medical Insights 5
Patients remain contagious from 1-2 days before rash onset until all lesions are crusted, according to the Centers for Disease Control and Prevention (MMWR Recommendations and Reports) 4, 6

Individuals who received varicella vaccine still harbor latent vaccine-strain VZV in their ganglia and remain at risk for shingles, though this risk appears lower than after wild-type infection, as stated by the American Academy of Pediatrics 3 and the Journal of Microbiology, Immunology and Infection 1