Comparative study of clinical and epidemiological characteristics of major pediatric adenovirus epidemics in southern Taiwan

Human adenovirus species B knob proteins as immunogens for inducing cross-neutralizing antibody responses

The re-emerging human adenovirus (HAdV) types 3, 7, 14, and 55 of species B have caused severe or even fatal acute respiratory disease. Therefore, the development of multivalent vaccines against HAdV types 3, 7, 14, and 55 remains an important goal. In our previous study, we identified a cross-neutralizing epitope that induced broadly reactive monoclonal neutralizing antibodies against the knob proteins of HAdV types 7, 11, 14, and 55. To study the immunogenicity of HAdV species B knob proteins, we evaluated humoral immune responses to the knob proteins in vivo and in vitro. We found that the knob proteins elicited robust binding and neutralizing antibody responses after three immunizations of mice. In addition, mouse antisera raised against the knob proteins exhibited cross-neutralizing activity against original species B members. Furthermore, immunization with a mix of HAdV-3, 7, and 55 knob proteins protected Chinese tree shrews against an experimental HAdV challenge. Our results provide insight into the immunogenicity of HAdV species B knob proteins.IMPORTANCEHuman adenovirus (HAdV) species B are common pathogens causing severe pneumonia in children, and there is currently no vaccine available. Because there are many HAdV species B types, developing broad-spectrum vaccines against HAdV species B is an important research goal. Our study revealed that immunization with recombinant HAdV species B knob proteins effectively elicited cross-neutralizing antibody responses against original species B members with protective immunity. This study provides a novel insight into the immunogenicity of HAdV species B knob proteins.

Clinical Characteristics of 204 Children With Human Adenovirus Type 7 Pneumonia Identified by Whole Genome Sequencing in Liuzhou, China

BACKGROUND

Clinical knowledge of human adenovirus type 7 (HAdV-7) pneumonia in children remains limited. Moreover, predictors for disease severity are largely unknown.

METHODS

This is a retrospective study of children hospitalized at Liuzhou Maternal and Child Health Hospital, China, with HAdV-7 pneumonia in 2018-2019. Demographics, clinical characteristics, laboratory results, and imaging data were collected. HAdV-7 was identified in plasma using whole genome sequencing, which yielded quantitative HAdV-7 sequence numbers.

RESULTS

There were 204 children; 145 (71%) were <2 years of age. There were 68 children with severe pneumonia (SP) and 136 with nonsevere pneumonia (NSP). Up to 43% in SP group with respiratory failure (SP-RF) were <12 months of age. Median duration of fever before hospitalization was shorter in NSP group than SP groups (P < 0.01). Fourteen (6.9%) underwent mechanical ventilation. There was a significant difference in mean plasma HAdV-7 sequence numbers among SP-RF, SP without respiratory failure (SP-NRF), and NSP groups (2485 ± 165, 2034 ± 124, and 286 ± 35, respectively) (P < 0.01). In a logistic regression analysis, we found that elevated plasma HAdV-7 sequence numbers significantly increased the risk of severe HAdV-7 pneumonia (OR 1.80, 95% confidence interval: 1.59-2.60, P < 0.01) after adjusting for age, fever duration, platelet counts, and serum lactate dehydrogenase levels.

CONCLUSIONS

Over two-thirds of children hospitalized with HAdV-7 pneumonia were <2 years of age. Approximately 40% of those with SP associated with respiratory failure were <12 months of age. Those with SP exhibited higher plasma HAdV-7 sequence numbers. Thus, plasma HAdV-7 sequence numbers have a potential in predicting severity of HAdV-7 pneumonia in children.