A variety of non-pharmaceutical interventions (NPIs) have been implemented to control the transmission of COVID-19 in China. The effect of NPIs on other common respiratory viruses in children of different age groups has not been examined thus far. Respiratory specimens of children were collected to detect common childhood respiratory viruses, including influenza A (FluA), influenza B (FluB), adenovirus, and respiratory syncytial virus (RSV), at the Children'

The novel coronavirus 2019 (COVID‐19) caused by SARS‐CoV‐2 spread rapidly worldwide, posing a severe threat to public life and health. It is significant to realize rapid testing and timely control of epidemic situations under the condition of limited resources. However, laboratory‐based standardized nucleic acid detection methods have a long turnaround time and high cost, so it is urgent to develop convenient methods for detecting COVID‐19. This paper summarizes the point‐of‐care testing (POCT) developed for novel coronavirus from three aspects: nucleic acid extraction, nucleic acid amplification, and detection methods. This paper introduces a commercial real‐time detection system that integrates the abovementioned three steps and the matters needing attention in use. The primary purpose of this review is to provide a reference for emergency response and rapid deployment of COVID‐19 and some other emerging infectious diseases.

Severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) nucleic acid detection is the gold standard for the laboratory diagnosis of coronavirus disease 2019 (COVID‐19). However, this method has high requirements for practitioners' skills and testing sites, so it is not easy to popularize and promote the application in places other than large hospitals. In addition, the detection flux of SARS‐CoV‐2 nucleic acid is small, and the whole detection process takes much time, which cannot meet the actual needs of rapid screening in large quantities. The WHO conditionally approved a batch of SARS‐CoV‐2 antigen reagents for clinical application to alleviate this contradiction. SARS‐CoV‐2 antigen detection offers a trade‐off among clinical performance, speed and accessibility. With the gradual increase in clinical application, the accumulated clinical data show that the sensitivity and specificity of the SARS‐CoV‐2 antigen assay are over 80% and 97%, respectively, which can basically meet the requirements of the WHO. However, the sensitivity of the SARS‐CoV‐2 Antigen Assay among asymptomatic people in low prevalence areas of COVID‐19 cannot meet the standard, leading to a large number of missed diagnoses. In addition, the detection ability of SARS‐CoV‐2 antigen reagent for different SARS‐CoV‐2 mutant strains differs greatly, especially for those escaping the COVID‐19 vaccines. In terms of results interpretation, it is highly reliable to exclude SARS‐CoV‐2 infection based on the high negative predictive value of the SARS‐CoV‐2 antigen assay. However, in the low prevalence environment, the probability of false positives of the SARS‐CoV‐2 antigen assay is high, so the positive results need to be confirmed by the SARS‐CoV‐2 nucleic acid reagent. The SARS‐CoV‐2 antigen assay is only a supplement to SARS‐CoV‐2 nucleic acid detection and can never completely replace it. To date, SARS‐CoV‐2 nucleic acid detection continues to be the standard laboratory method for COVID‐19 diagnosis.

Precise prevention and control measures have been adopted to impede the transmission of coronavirus disease 2019 (COVID‐19) in China. This study was performed to investigate the effect of protective measures on gastrointestinal infection in children during the COVID‐19 pandemic. The data on the rotavirus and adenovirus antigen tests were collected in outpatient children due to gastroenteritis from January 1, 2019 to December 31, 2020, at the Children's Hospital of Zhejiang University School of Medicine. According to age and month distribution, the positive number and rate of rotavirus and adenovirus in 2020 were compared with 2019. A 3.8‐fold and 4‐fold reduction in the number of rotavirus‐ and adenovirus‐positive patients in 2020 were found, respectively. The overall positive rate of rotavirus and adenovirus infection was drastically decreased in 2020 (rotavirus 2020: 18.18% vs. 2019: 9.75%, p < 0.001; adenovirus 2020: 3.13% vs. 2019: 1.58%, p < 0.001). The proportions of rotavirus and adenovirus in all age groups in 2020 decreased compared with those in 2019. The highest frequency of rotavirus infection occurred among children aged 1–3 years both in 2019 and 2020 (2019: 27.95% vs. 2020: 17.19%, p < 0.001), while adenovirus infection was detected in children aged 3–5 years, which had the highest percent positivity (2019: 8.19% vs. 2020: 4.46%; p < 0.001). An obvious peak prevalence of rotavirus incidence was found during December–April, and the percent positivity of rotavirus significantly decreased in 2020 (December 2019: 24.26% vs. 2020: 8.44%, p < 0.001; January 2019: 40.67% vs. 2020: 38.18%, p < 0.05; February 2019: 40.73% vs. 2020: 15.04%, p < 0.001; March 2019: 31.47% vs. 2020: 7.88%, p < 0.001; April 2019: 15.52% vs. 2020: 4.78%, p < 0.001). The positive rate of adenovirus distributed throughout 2019 was 1.91%–4.86%, while the percent positivity during 2020 in the same period was much lower (0.00%–3.58%). Our results confirmed that the preventive and control measures adopted during the COVID‐19 pandemic and the collateral benefit of these interventions have significantly decreased the transmission of rotavirus or adenovirus.

During the COVID‐19 epidemic, nonpharmaceutical interventions (NPIs) blocked the transmission route of respiratory diseases. This study aimed to investigate the impact of NPIs on the influenza A virus (IAV) outbreak. The present study enrolled all children with respiratory tract infections who came to the Children's Hospital of Zhejiang University between January 2019 and July 2022. A direct immunofluorescence assay kit detected IAV. Virus isolation and Sanger sequencing were performed. From June to July 2022, in Hangzhou, China, the positive rate of IAV infection in children has increased rapidly, reaching 30.41%, and children over 3 years old are the main infected population, accounting for 75% of the total number of infected children. Influenza A (H3N2) viruses are representative strains during this period. In this outbreak, H3N2 was isolated from a cluster of its own and is highly homologous with A/South_Dakota/22/2022 (2021–2022 Northern Hemisphere). Between isolated influenza A (H3N2) viruses and A/South_Dakota/22/2022, the nucleotide homology of the HA gene ranged from 97.3% to 97.5%; the amino acid homology was 97%–97.2%, and the genetic distance of nucleotides ranged from 0.05 to 0.052. Compared with A/South_Dakota/22/2022, the isolated H3N2 showed S156H, N159Y, I160T, D186S, S198P, I48T, S53D, and K171N mutations. There was no variation in 13 key amino acid sites associated with neuraminidase inhibitor resistance in NA protein. Long‐term NPIs have significantly affected the evolution and transmission of the influenza virus and human immunity, breaking the dynamic balance between the IAV and human immunity.