Prospective surveillance of human adenovirus in acute respiratory infections reveals epidemiological features and the disappearance of species B during the COVID-19 pandemic in Beijing, China

A significant outbreak of respiratory human adenovirus infections among children aged 3-6 years in Hokkaido, Japan, in 2023

Human adenovirus (HAdV) infections present diverse clinical manifestations upon infecting individuals, with respiratory infections predominating in children. We surveyed pediatric hospitalizations due to respiratory HAdV infections across 18 hospitals in Hokkaido Prefecture, Japan, from July 2019 to March 2024, recording 473 admissions. While hospitalizations remained below five cases per week from July 2019 to September 2023, a notable surge occurred in late October 2023, with weekly admissions peaking at 15-20 cases from November to December. There were dramatic shifts in the age distribution of hospitalized patients: during 2019-2021, 1-year-old infants and children aged 3-6 years represented 51.4%-54.8% and 4.1%-13.3%, respectively; however, in 2023-2024, while 1-year-old infants represented 19.0%-20.1%, the proportion of children aged 3-6 years increased to 46.2%-50.0%. Understanding the emergence of significant outbreaks of respiratory HAdV infections and the substantial changes in the age distribution of hospitalized cases necessitates further investigation into the circulating types of HAdV in Hokkaido Prefecture and changes in children's neutralizing antibody titers against HAdV.

Genetic characterization of pediatric SARI-associated human adenoviruses in eight Chinese provinces during 2017-2021

Human adenovirus (HAdV) is a significant viral pathogen causing severe acute respiratory infections (SARIs) in children. To improve the understanding of type distribution and viral genetic characterization of HAdV in severe cases, this study enrolled 3404 pediatric SARI cases from eight provinces of China spanning 2017-2021, resulting in the acquisition of 112 HAdV strains. HAdV-type identification, based on three target genes (penton base, hexon, and fiber), confirmed the diversity of HAdV types in SARI cases. Twelve types were identified, including species B (HAdV-3, 7, 55), species C (HAdV-1, 2, 6, 89, 108, P89H5F5, Px1/Ps3H1F1, Px1/Ps3H5F5), and E (HAdV-4). Among these, HAdV-3 exhibited the highest detection rate (44.6%), followed by HAdV-7 (19.6%), HAdV-1 (12.5%), and HAdV-108 (9.8%). All HAdV-3, 7, 55, 4 in this study belonged to dominant lineages circulating worldwide, and the sequences of the three genes demonstrated significant conservation and stability. Concerning HAdV-C, excluding the novel type Px1/Ps3H1F1 found in this study, the other seven types were detected both in China and abroad, with HAdV-1 and HAdV-108 considered the two main types of HAdV-C prevalent in China. Two recombinant strains, including P89H5F5 and Px1/Ps3H1F1, could cause SARI as a single pathogen, warranting close monitoring and investigation for potential public health implications. In conclusion, 5 years of SARI surveillance in China provided crucial insights into HAdV-associated respiratory infections among hospitalized pediatric patients.

Genome sequencing reveals molecular epidemiological characteristics and new recombinations of adenovirus in Beijing, China, 2014-2019

To investigate the molecular epidemiological characteristics and genetic variations of human adenovirus (HAdV) in acute respiratory tract infections in Beijing. Whole-genome sequencing and phylogenetic analyses were performed for 83 strains of HAdV with different types in Beijing from 2014 to 2019. The clinical characteristics of HAdV infection were analyzed statistically. HAdV-B was divided into four genotypes, including B3 (n = 11), B7 (n = 13), B14 (n = 4), and B55 (n = 2). HAdV-C was divided into three genotypes, including C1 (n = 14), C2 (n = 13), and C5 (n = 10). In HAdV-C, nine recombinant adenovirus strains were identified in type 1, and seven recombinant strains were found in type 2. In type 1, we found three newly emerged intraspecific recombinant strains (A47, A48, and A52) collected in 2017, 2018, and 2019, respectively. In addition, the previously reported recombinant strains of HAdV-C1 showed more severe disease than other strains of HAdV-C, causing severe community-acquired pneumonia in both the elderly and children. Continuous population-wide molecular epidemiological surveillance of HAdV is essential for the prevention and control of respiratory infectious diseases.

Influence of COVID-19 pandemic on the virus spectrum in children with respiratory infection in Xuzhou, China: a long-term active surveillance study from 2015 to 2021

BACKGROUND

To investigate the impact of the coronavirus disease 2019 (COVID-19) outbreak on the prevalence of respiratory viruses among pediatric patients with acute respiratory infections in Xuzhou from 2015-2021.

METHODS

Severe acute respiratory infection (SARI) cases in hospitalized children were collected from 2015-2021 in Xuzhou, China. Influenza virus(IFV), respiratory syncytial virus (RSV), human parainfluenza virus type 3(hPIV-3), human rhinovirus (hRV), human adenovirus(hAdV), human coronavirus(hCoV) were detected by real-time fluorescence polymerase chain reaction(RT-qPCR), and the results were statistically analyzed by SPSS 23.0 software.

RESULTS

A total of 1663 samples with SARI were collected from 2015-2021, with a male-to-female ratio of 1.67:1 and a total virus detection rate of 38.5% (641/1663). The total detection rate of respiratory viruses decreased from 46.2% (2015-2019) to 36% (2020-2021) under the control measures for COVID-19 (P < 0.01). The three viruses with the highest detection rates changed from hRV, RSV, and hPIV-3 to hRV, RSV, and hCoV. The epidemic trend of hPIV-3 and hAdV was upside down before and after control measures(P < 0.01); however, the epidemic trend of RV and RSV had not changed from 2015 to 2021(P > 0.05). After the control measures, the detection rate of hPIV-3 decreased in all age groups, and the detection rate of hCoV increased in all except the 1 ~ 3 years old group.

CONCLUSIONS

Implementing control measures for COVID-19 outbreak curbed the spread of respiratory viruses among children as a whole. However, the epidemic of RV and RSV was not affected by the COVID-19 control policy.

The changed endemic pattern of human adenovirus from species B to C among pediatric patients under the pressure of non-pharmaceutical interventions against COVID-19 in Beijing, China

BACKGROUND

Under the pressure of non-pharmaceutical interventions (NPIs) targeting severe acute respiratory syndrome coronavirus 2, the prevalence of human adenovirus (HAdV) was monitored before and after NPIs launched on Jan 24, 2020 in pediatric patients in Beijing, China.

METHODS

Respiratory samples collected from children hospitalized with acute respiratory infections from Jan 2015 to Dec 2021 were screened by direct immunofluorescence test or capillary electrophoresis-based multiplex PCR assay. The hexon, penton base, and fiber genes were amplified from HAdV positive specimens, then sequenced. For HAdV typing, phylogenetic trees were built by MEGA X. Then clinical data of HAdV positive cases were collected. All data were evaluated using SPSS Statistics 22.0 software.

RESULTS

A total of 16,097 children were enrolled and 466 (2.89%, 466/16,097) were HAdV-positive. The positive rates of HAdV varied, ranging from 4.39% (151/3,438) in 2018 to1.25% (26/2,081) in 2021, dropped from 3.19% (428/13,408) to 1.41% (38/2,689) from before to after NPIs launched (P < 0.001). There were 350 cases typed into nine types of species B, C, or E and 34 recorded as undetermined. Among them, HAdV-B3 (51.56%, 198/384) was the most prevalent types from 2015 to 2017, and HAdV-B7 (29.17%, 112/384) co-circulated with HAdV-B3 from 2018 to 2019. After NPIs launched, HAdV-B3 and B7 decreased sharply with HAdV-B7 undetected in 2021, while HAdV-C1 became the dominant one and the undetermined were more.

CONCLUSIONS

The endemic pattern of HAdV changed in Beijing because of the NPIs launched for COVID-19. Especially, the dominant types changed from HAdV-B to HAdV-C.