Co-infections of adenovirus species in previously vaccinated patients

Abstract

Despite the success of the adenovirus vaccine administered to US military trainees, acute respiratory disease (ARD) surveillance still detected breakthrough infections (respiratory illnesses associated with the adenovirus serotypes specifically targeted by the vaccine). To explore the role of adenoviral co-infection (simultaneous infection by multiple pathogenic adenovirus species) in breakthrough disease, we examined specimens from patients with ARD by using 3 methods to detect multiple adenoviral species: a DNA microarray, a polymerase chain reaction (PCR)-enzyme-linked immunosorbent assay, and a multiplex PCR assay. Analysis of 52 samples (21 vaccinated, 31 unvaccinated) collected from 1996 to 2000 showed that all vaccinated samples had co-infections. Most of these co-infections were community-acquired serotypes of species B1 and E. Unvaccinated samples primarily contained only 1 species (species E) associated with adult respiratory illness. This study highlights the rarely reported phenomenon of adenoviral co-infections in a clinically relevant environment suitable for the generation of new recombinational variants.

Figure

Molecular methods used to identify human adenovirus (HAdV) co-infections. A–D) Vaccinated sample 7274. A) Microarray hybridization profile. White and yellow rectangles indicate low-positive HAdV-C and HAdV-B2 targets, respectively. Spot colors denote hybridization signal intensity (white > yellow > green > blue). Species and corresponding serotype designations are indicated on the left. Probe designations (E1, E2 = serotype-specific E1A probes; H1, H2 = serotype-specific hexon probes; F1, F2 = serotype-specific fiber probes) are indicated above each array. B) Adenovirus Consensus kit optical density values. *, amplification positive. The horizontal line is the manufacturer's significance threshhold. C) Multiplex species-specific polymerase chain reaction (PCR). m, molecular mass marker. Species designations are to the right of the corresponding band. D) PCR verification with independent serotype or species-specific primers. E–H) Unvaccinated sample 10756. E) Microarray hybridization profile. F) Adenovirus Consensus kit optical density values. G) Multiplex species-specific PCR. H) PCR verification with independent serotype-specific primers.