Varicella-Zoster Virus Infection

Pathophysiology: Little is known about the route and the source of transmission of the virus. VZV is certainly transmissible through the airborne route and does not require close personal contact. The skin lesions are certainly full of infectious virus particles whilst in contrast, it is almost impossible to isolate virus from the upper respiratory tract. It is possible that aerial transmission originates from symptomless oral lesions.

Disease statistics: Clinical symptoms were reported in 580 of 8429 vaccinees (7 percent), and seroconversion was documented in 2347 of 2565 (92 percent). Evidence of humoral and cellular immunity to VZV persisted in 26 vaccine recipients for > 20 years. Despite 100 documented contacts with varicella patients, only two vaccines (2 percent) developed breakthrough varicella with mild clinical features within 12 months of vaccination.

Treatment: Several studies indicate that antiviral medications decrease the duration of symptoms and the likelihood of postherpetic neuralgia, especially when initiated within 2 days of the onset of rash. In typical cases that involve individuals who are otherwise healthy, oral acyclovir may be prescribed. An important study by Kubeyinje (1997) suggested that the use of acyclovir in healthy young adults with zoster is not clearly justified, especially in situations of limited economic resources.

Research: Prospective studies of the vaccine in clinical practice are especially significant because of the likelihood that results will differ in this setting compared to research settings. A postlicensure case-control study involving otherwise healthy children is being carried out in the offices of pediatricians in New Haven, Conn. The “cases” are PCR-proven cases of varicella, and the “controls” are demographically matched children without varicella. This study, which is under way, has indicated that the vaccine as used in the United States is highly effective in preventing varicella (131).