Overview of three influenza seasons in Georgia, 2014-2017

Epidemiological characteristics of respiratory pathogens infections among children after the removal of non-pharmaceutical interventions in central China

BACKGROUND

During the COVID-19 pandemic between 2020 and 2022 in China, various non-pharmaceutical interventions (NPIs) were implemented to reduce the spread of SARS-CoV-2 and other respiratory pathogens. From 2023, China downgraded the management of COVID-19, and compliance with NPIs was no longer mandatory. This study aimed to reveal the epidemiological characteristics of respiratory pathogens in 2023 after the removal of NPIs in central China.

METHODS

Respiratory specimens of children with acute respiratory infections (ARIs) were obtained to detect seven common respiratory pathogens, including influenza A (FluA), influenza B (FluB), adenovirus (ADV), human rhinovirus (HRV), human respiratory syncytial virus (HRSV), human metapneumovirus (HMPV), Mycoplasma pneumoniae (MP). From January 2022 to December 2023, a total of 5423 specimens were collected, including 1122 children in 2022 and 4301 children in 2023.

RESULTS

One or more pathogens were detected in 62.50% specimens in 2023, significantly higher than that in 2022 (44.12%). HRV (13.81%) was the most common pathogen in 2022, whereas MP (24.67%) was predominant in 2023. There was no significant difference in the overall prevalence of HRV, HRSV and HMPV between 2022 and 2023. HRSV was the most common pathogen in the < 1 years children both in 2022 and 2023. However in the ≥ 7 years group, FluB was the predominant pathogen in 2022 whereas MP ranked first in 2023. Co-detection were significantly more frequent in 2023 compared to 2022.

CONCLUSIONS

The removal of NPIs significantly increased the infection rates of the respiratory pathogens among children. Some NPIs, such as wearing mask and hand hygiene are necessary to decrease the prevalence of certain pathogens.

Change of epidemiological characteristics of four respiratory viral infections in children before and during COVID-19 pandemic

OBJECTIVES

Viruses are the main infectious agents of acute respiratory infections (ARIs) in children. We aim to describe the changes in epidemic characteristics of viral ARIs in outpatient children before and during the COVID-19 pandemic.

PATIENTS AND METHODS

From 2017 to 2022, the results of viral detection in oral pharyngeal swabs in 479,236 children with ARIs in the outpatient department of Children's Hospital, Zhejiang University School of Medicine, were retrospectively analyzed. Viral antigens, including adenovirus (ADV), influenza A (FLUA), influenza B (FLUB) and respiratory syncytial virus (RSV) were detected by the colloidal gold method.

RESULTS

The median age was 3.4 (1.6-5.6) years. Among all the children, 159,895 cases (33.4 %) were positive for at least one virus. The total positive rate for ADV, FLUA and FLUB during the pandemic period was lower than during the pre-pandemic period in every season (pre-pandemic period vs. pandemic period11.7 % vs. 4.7 %, 13.9 % vs. 9.2 %, 7.0 % vs. 5.2 %, respectively, with overall p value < 0.001). However, the positive rate fir RSV was not significantly different between the pre-pandemic period and the pandemic period (5.6 % vs. 5.8 %, p = 0.117). Atypical timing of RSV (summer-autumn 2021) and FLUA (summer 2022) was noted.

CONCLUSIONS

Public health interventions for different pathogens are maximally effective. While positive rates for ADV, FLUA and FLUB decreased during the COVID-19 pandemic period, positive rates for RSV remained similar. In RSV and FLUA, off-season outbreaks were observed. Measures need to be taken to protect children from possible infection surges due to immunity debt having accrued over the last three years.

Changes in Influenza Activities Impacted by NPI Based on 4-Year Surveillance in China: Epidemic Patterns and Trends

BACKGROUND

Since the Non-pharmaceutical Intervention (NPI) by COVID-19 emerged, influenza activity has been somewhat altered.

OBJECTIVES

The aim of this study was to explore changes in influenza activities in the context of COVID-19 based on the sentinel hospitals/units in Guangdong, southern China.

METHODS

The surveillance data in influenza-like illness (ILI) were collected from 21 cities in Guangdong between September 2017 and August 2021, while 43 hospitals/units were selected to analyze the predominant types of influenza, population characteristics, and seasonal features by three methods (the concentration ratio, the seasonal index, and the circulation distribution), based on a descriptive epidemiological approach.

RESULTS

During the four consecutive influenza seasons, a total of 157345 ILIs were tested, of which 9.05% were positive for influenza virus (n = 14238), with the highest positive rates for both IAV (13.20%) and IBV (5.41%) in the 2018-2019 season. After the emergence of COVID-19, influenza cases decreased near to zero from March 2020 till March 2021, and the dominant type of influenza virus changed from IAV to IBV. The highest positive rate of influenza existed in the age-group of 5 ~  < 15 years in each season for IAV (P < 0.001), which was consistent with that for IBV (P < 0.001). The highest annual positive rates for IBV emerged in eastern Guangdong, while the highest annual positive rates of IAV in different seasons existed in different regions. Furthermore, compared with the epidemic period (ranged from December to June) during 2017-2019, the period ended three months early (March 2020) in 2019-2020, and started by five months behind (April 2021) during 2020-2021.

CONCLUSION

The highest positive rates in 5 ~  < 15 age-group suggested the susceptible in this age-group mostly had infected with infected B/Victoria. Influenced by the emergence of COVID-19 and NPI responses, the epidemic patterns and trends of influenza activities have changed in Guangdong, 2017-2021.

Epidemiological characteristics of four common respiratory viral infections in children

BACKGROUND

Viruses are the main infectious agents of acute respiratory infections in children. We aim to describe the epidemiological characteristics of viral pathogens of acute respiratory tract infections in outpatient children.

METHODS

From April 2018 to March 2019, the results of viral detection using oral pharyngeal swabs from 103,210 children with acute respiratory tract infection in the outpatient department of the Children's Hospital, Zhejiang University School of Medicine, were retrospectively analyzed. Viral antigens, including adenovirus (ADV), influenza A (FLUA), influenza B (FLUB) and respiratory syncytial virus (RSV), were detected by the colloidal gold method.

RESULTS

At least one virus was detected in 38,355 cases; the positivity rate was 37.2%. A total of 1910 cases of mixed infection with two or more viruses were detected, and the positivity rate of multiple infection was 1.9%. The ADV positivity rate was highest in the 3-6-year-old group (18.7%), the FLUA positivity rate was highest in the > 6-year-old group (21.6%), the FLUB positivity rate was highest in the > 6-year-old group (6.6%), and the RSV positivity rate was highest in the < 1-year-old group (10.6%). There was a significant difference in the positivity rate of viral infection among different age groups (χ² = 1280.7, P < 0.001). The rate of positive viral infection was highest in winter (47.1%). The ADV infection rate was highest in spring (18.2%). The rates of FLUA and FLUB positivity were highest in winter (28.8% and 3.6%, respectively). The rate of RSV positivity was highest in autumn (17.4%). The rate of positive viral infection in different seasons was significantly different (χ² = 6459.1, P < 0.001).

CONCLUSIONS

Viral infection rates in children differ for different ages and seasons. The positivity rate of ADV is highest in the preschool period and that of RSV is highest in infants; that of FLU increases with age. The total positive rate of viral infection in different seasons is highest in winter, as is the rate of FLU positivity.

Influenza A and B in a cohort of outpatient children and adolescent with influenza like-illness during two consecutive influenza seasons

INTRODUCTION

Influenza is an important cause of morbimortality worldwide. Although people at the extremes of age have a greater risk of complications, influenza has been more frequently investigated in the elderly than in children, and inpatients than outpatients. Yearly vaccination with trivalent or quadrivalent vaccines is the main strategy to control influenza.

OBJECTIVES

Determine the clinical and molecular characteristics of influenza A and B infections in children and adolescents with influenza-like illness (ILI).

METHODS

A cohort of outpatient children and adolescents with ILI was followed for 20 months. Influenza was diagnosed with commercial multiplex PCR platforms.

RESULTS

179 patients had 277 episodes of ILI, being 79 episodes of influenza A and 20 episodes of influenza B. Influenza A and B cases were mild and had similar presentation. Phylogenetic tree of influenza B viruses showed that 91.6% belonged to the B/Yamagata lineage, which is not included in trivalent vaccines.

CONCLUSIONS

Influenza A and B are often detected in children and adolescents with ILI episodes, with similar and mild presentation in outpatients. The mismatch between the circulating influenza viruses and the trivalent vaccine offered in Brazil may have contributed to the high frequency of influenza A and B in this population.