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

Abstract

The authors of a recent study suggested that the duration of deferral for blood donations by smallpox vaccinees should be extended, based on detection of vaccinia virus DNA in 5 blood samples by PCR and the potential for viremia. We found that 4 of 202 blood specimens (from 3 of 27 smallpox vaccinees) were positive for vaccinia virus DNA by PCR; none were positive for virus by culture. Throat swabs were negative by PCR and culture. Thus, while some blood specimens contained vaccinia virus DNA, infectious virus was not detected. Current guidelines for deferral of blood donation in vaccinees seem appropriate.

Human Vaccinia virus and Pseudocowpox virus co-infection: Clinical description and phylogenetic characterization

“…To date, other studies have described the detection of OPV or PPV-DNA in the blood related with the acute-phase of the diseases. [15][16][17] Although other reports have described the circulation of PPV in Brazil, 8,10 our study is the first to specifically describe the detection of a PCPV in Brazil. The PPV phylogenetic-tree (Fig.…”

Natural human infections with Vaccinia virus during bovine vaccinia outbreaks

“…Nitsche et al 28 showed the longlasting DNAemia of the Cowpox virus in humans, and the presence of IgG and IgM were not sufficient to resolve infection. Other works involving VACV-vaccinated patients demonstrated viral DNA in blood until 20 days post-vaccination, 29,30 as well as in accidental post-vaccination VACV infections (eczema vaccinatum). 31 Interestingly, our results indicate that natural VACV infection follows an analogous model once viral DNA is detected until 1 month postinitial clinical symptoms in serum ( Table 2).…”

Orthopox Viruses: Infections in Humans

“…In some studies, viraemia was detected by PCR up to 21 days following an immunisation [3]. Other authors did not succeed in detecting VACV DNA in the blood, or did so only in isolated cases, and even then, only in a short time interval after the vaccination [36,122,123]. Infectious virus could not be detected in these investigations.…”