Kinetics of serum cytokines after primary or repeat vaccination with the smallpox vaccine.

Background: The smallpox vaccine is associated with more serious adverse events than any other live attenuated vaccine in use today. Although studies have examined serum cytokine levels in primary vaccine recipients at 1 and 3-5 weeks after vaccination with the smallpox vaccine, serial measurements have not been performed, and studies in revaccinated subjects have not been conducted.

Methods: We analyzed cytokine responses in both primary vaccine recipients and revaccinated subjects every other day for 2 weeks after vaccination.

Long-term administration of valacyclovir reduces the number of Epstein-Barr virus (EBV)-infected B cells but not the number of EBV DNA copies per B cell in healthy volunteers.

Epstein-Barr virus (EBV) establishes a latent infection in B cells in the blood, and the latent EBV load in healthy individuals is generally stable over time, maintaining a "set point." It is unknown if the EBV load changes after long-term antiviral therapy in healthy individuals. We treated volunteers with either valacyclovir (valaciclovir) or no antiviral therapy for 1 year and measured the amount of EBV DNA in B cells every 3 months with a novel, highly sensitive assay.

Detection of vaccinia virus DNA, but not infectious virus, in the blood of smallpox vaccine recipients.

The authors of a recent study [Savona MR, Dela Cruz WP, Jones MS, Thornton JA, Xia D, Hadfield TL, et al. Detection of vaccinia DNA in the blood following smallpox vaccination. JAMA 2006; 295:1898-1900] suggested that the duration of deferral for blood donations by smallpox vaccinees should be extended, based on detection of vaccinia virus DNA in five blood samples by polymerase chain reaction (PCR) and the potential for viremia.

Comparison of methods for detection of vaccinia virus in patient specimens.

We analyzed a shell vial culture assay (SVA), real-time PCR, and a direct fluorescent antibody assay (DFA) for rapid detection of vaccinia virus from vaccination sites of Dryvax vaccine recipients. Of 47 samples assayed, 100% were positive by PCR, 89% were positive by SVA, and 40% were positive by DFA. DFA was limited by the need for adequate numbers of cells, with 32% of samples inadequate for interpretation.