Seroprevalence of neutralizing antibodies against human adenovirus type 55 in the South Korean military, 2018-2019.

So Yun Park,Bo-Young Jeon,Jae-Hoon Ko,Jonguk Jeong,Soon-Hwan Kwon,Sezim Monoldorova,Nancy M Sawtell

doi:10.1371/journal.pone.0236040

Abstract

We conducted a seroprevalence study of a large ongoing outbreak of human adenovirus type 55 (HAdV-55) among the military in South Korea. Serum samples were collected between 2018 and 2019 from military-exposed (military group) and non-exposed (non-military group) populations. The plaque reduction neutralization test (PRNT) was used to assess neutralization activity against HAdV-55. A total of 100 sera was collected from the non-military group, of which 18.8% showed HAdV-55 neutralizing antibody activity. Ninety-six sera were tested from the military group, which had significantly higher prevalence of neutralizing antibodies (56.0%, P <0.001). A significantly higher proportion of the military group had PRNT titers ≥1:1,000 than the non-military group (85.7% vs. 50.0%, P = 0.004). Among the military group, 48.9% of active-duty soldiers had PRNT titers ≥1:5,000, while none of the discharged civilians did (P = 0.007). In conclusion, Koreans were exposed to HAdV-55 in their communities, but the exposure risk was higher among people in military service.

Highlights

Human adenovirus type 55 (HAdV-55) is an emerging recombinant HAdV strain of types 11 and 14, causing a potentially fatal acute respiratory illness (ARI) in adult populations [1, 2]
To evaluate HAdV-55 seroprevalence in Korean society, we collected serum samples from four distinct populations: 1) healthy civilian volunteers, including male citizens discharged from obligatory military service; 2) new military recruits collected during the entrance medical examination; 3) active-duty soldiers admitted to a military hospital for ARI caused by respiratory viruses other than HAdV; and 4) active-duty soldiers after one year of service, collected during routine medical examinations
The only epidemiologic investigation of HAdV-55 in a civilian community has been conducted in China, where several fatal HAdV-55 pneumonia cases have occurred among civilians [2, 6]

Summary

Introduction

Human adenovirus type 55 (HAdV-55) is an emerging recombinant HAdV strain of types 11 and 14, causing a potentially fatal acute respiratory illness (ARI) in adult populations [1, 2]. Seroprevalence of HAdV-55 in Korea the military and is currently considered a major pathogen of severe pneumonia among military personnel [10, 11]. A molecular typing study of respiratory HAdV in the Korean civilian community has not been conducted since 2010 [12], and the current epidemiologic status of HAdV-55 among Koreans who have been discharged from military service is unknown. In May 2017, the first HAdV-55 outbreak among the Korean civilian community was reported from a high school, emphasizing the need for an epidemiologic investigation of HAdV-55 in Korea [13]. We investigated seroprevalence and distribution of neutralizing antibodies (nAb) against HAdV-55 and HAdV-4 among healthy civilian volunteers and military personnel in various settings

Methods

Laboratory procedures

Results

Discussion