[Epidemiological characteristics of human respiratory syncytial virus in patients with severe acute respiratory infection in Tianjin City from 2015 to 2020].

Objective: To investigate the epidemiological characteristics of human respiratory syncytial virus (HRSV) in patients with Severe Acute Respiratory Infection (SARI) in Tianjin from 2015 to 2020. Methods: The study data were obtained from the Third Center Hospital of Tianjin, a designated sentinel hospital, from 2015 to 2020, with 1 597 SARI patients enrolled in this study. The clinical specimens of the research participants were subjected to respiratory multi-pathogen testing. HRSV-positive specimens were subtyped to analyze the differences in HRSV detection rates among cases of different age groups and periods and their mixed infection situations. Results: A total of 1 597 nasopharyngeal swabs were collected, with an HRSV detection rate of 4.20%. Among 67 HRSV-positive specimens, there were 19 pure HRSV-A nucleic acid-positive specimens, 19 pure HRSV-B nucleic acid-positive specimens and 29 mixed HRSV-A and HRSV-B nucleic acid-positive specimens. The difference in HRSV detection rate among different age groups was statistically significant (P<0.05), and the HRSV detection rate in children under five years old was higher than that in other age groups. From 2016 to 2020, the detection rate of HRSV showed an increasing trend year by year. The HRSV detection rate of SARI cases was highest in the winter season, at 7.15%. There were 10 (14.93%) mixed positive cases for HRSV and other viruses, of which four were mixed positive for HRSV and influenza A. Conclusion: The incidence of HRSV in Tianjin exhibits an increasing trend from 2016 to 2020, peaking during the winter season, with children under five years old constituting a high-risk demographic for HRSV infection.

[Transmission characteristics and risk factors of household COVID-19 clusters caused by 2019-nCoV Omicron variant in Tianjin].

Objective: To understand the transmission characteristics and risk factors of household COVID-19 clusters caused by 2019-nCoV Omicron variant in Tianjin and provide evidence for COVID-19 prevention and control. Methods: Field epidemiological method was used to investigate the epidemiological characteristics of COVID-19 cases, and descriptive analysis was used to describe the epidemiological information. Results: A total of 430 cases were reported in this epidemic in Tianjin, in which 409 cases were included in this study. Among these cases, 70.90% (290/409) occurred in families. The family secondary attack rate was 33.64% The family secondary attack rate in age group 12-17 years (13.79%) was significantly lower than that in age group 18-49 years (36.48%), the OR was 0.378 (95%CI: 0.170-0.840). The logistic regression analysis showed that compared with centralized quarantine, the OR of the index cases found in closed-off/controlled areas and in home quarantine were 2.951 (95%CI:1.322-6.586) and 2.287 (95%CI:1.164-4.495), respectively, compared with the cases without sore throat, the OR of the index cases with sore throat was 3.003 (95%CI: 1.576-5.720), and compared with cases in families without completed COVID-19 vaccinations in all members, the OR of the cases in families with completed COVID-19 vaccinations in all members was 0.268 (95%CI: 0.132-0.552). Conclusions: The risk of household transmission of infection with Omicron variant was high. Detecting the index case in closed-off/controlled areas or in home quarantine and sore throat in index cases were the risk factors of the household transmission, completed COVID-19 vaccination was the protective factor.