New Respiratory Viruses and the Elderly

Jartti, Laura; Langen, Henriikka; Söderlund-Venermo, Maria; Vuorinen, Tytti; Ruuskanen, Olli; Jartti, Tuomas

Although HBoV infections are usually diagnosed with PCR, serological studies have shown that the mere presence of HBoV DNA in the respiratory tract is not proof of an acute primary HBoV infection [62, [73] [74] [75] . Studies on consecutive NPA samples have indeed shown that HBoV DNA can persist in the nasopharynx for several months [76, 77] . Among adults, over 94% have antibodies to HBoV, indicating that they have encountered this virus during their lives [78, 79] . The prevalence figure is high and shows that HBoV infections are extremely common. Only a limited number of HBoV DNA-positive adults have been reported, mainly among immunosuppressed subjects, an observation that is in line with the high seroprevalence of HBoV [80] [81] [82] [83] [84] . This age pattern was, however, interestingly contradicted by a Canadian study that did not find differences in the prevalence of HBoV among different age groups [85] . In adults, HBoV-DNA positivity seems to be associated with symptoms, and therefore, HBoV cannot be considered simply an innocent bystander virus [81, 83, 86] . Since the discovery of HBoV, three other related bocaviruses (HBoV2, 3 and 4) have been identified in human stool samples [69, 87, 88] .