Progress in research of influenza vaccination in pregnant women / 中华流行病学杂志

Influenza is an acute respiratory infectious disease caused by influenza virus. Pregnancy is associated with physiologic and immunological changes that may increase the risk for influenza virus infection and influenza-related complications. Influenza vaccination is the most effective way to prevent influenza virus infection. WHO and many countries have classified pregnant women as a priority population for influenza vaccination, however, there are still many challenges for promoting influenza vaccination in pregnant women in China, influenza vaccination coverage in pregnant women remains low and some influenza vaccine package inserts list pregnancy as an absolute contraindication. In this paper, we summarize the research progress in the effects of influenza infection and influenza vaccination during pregnancy both at home and abroad, then discuss the strategies to promote influenza vaccination in pregnancy for the purpose of providing reference for the related research and policy development in China.

Performance of screening of contacts of COVID-19 cases in same flight / 中华流行病学杂志

Objective: To understand the performance of 2019-nCoV nucleic acid detection in screening of contacts of COVID-19 cases in same flights and provide evidence for the effective screening of persons at high risk for the infection in domestic flights. Methods: The information of passengers who took same domestic flights with COVID-19 cases in China from April 1, 2020 to April 30, 2022 were retrospectively collected,and χ2 test was used to analyze positive nucleic acid detection rates in the passengers in different times before the onsets of the index cases, in different seat rows and in epidemic periods of different 2019-nCoV variants. Results: During the study period, a total of 433 index cases were identified among 23 548 passengers in 370 flights. Subsequently, 72 positive cases of 2019-nCoV nucleic acid were detected in the passengers, in whom 57 were accompanying persons of the index cases. Further analysis of the another 15 passengers who tested positive for the nucleic acid showed that 86.67% of them had onsets or positive detections within 3 days after the diagnosis of the index cases, and the boarding times were all within 4 days before the onsets of the index cases. The positive detection rate in the passengers who seated in first three rows before and after the index cases was 0.15% (95%CI: 0.08%-0.27%), significantly higher than in the passengers in other rows (0.04%, 95%CI: 0.02%-0.10%, P=0.007),and there was no significant difference in the positive detection rate among the passengers in each of the 3 rows before and after the index cases (P=0.577). No significant differences were found in the positive detection rate in the passengers, except the accompanying persons, among the epidemics caused by different 2019-nCoV variants (P=0.565). During the Omicron epidemic period, all the positive detections in the passengers, except the accompanying persons, were within 3 days before the onset of the index cases. Conclusions: The screening test of 2019-nCoV nucleic acid can be conducted in the passengers took the same flights within 4 days before the onsets of the index cases on board. Passengers who seated within 3 rows from the index cases can considered as the close contacts at high risk for 2019-nCoV, for whom screening should be conducted first and special managements are needed. The passengers in other rows can be classified as general risk persons for screening and management.

Overview of systematic reviews of Chinese herbal injections for sepsis / 中国中药杂志

In this study, an overview of systematic reviews/Meta-analysis(SR/MA) of Chinese herbal injections for sepsis was performed to provide references for clinical practice and promote the quality improvement of clinical evidence. Eight Chinese and English databases such as CNKI, Medline, and EMbase were electronically searched for SR/MA of Chinese herbal injections for sepsis from database inception to June 2022. AMSTAR 2, PRISMA 2020, and GRADE system, combined with Recommendations for Clinical Evidence Grading on Traditional Chinese Medicine Based on Evidence Body, were applied to evaluate the methodological quality, reporting quality, and evidence quality of the included articles. Twenty-seven articles of SR/MA were included, containing four Chinese herbal injections(Xuebijing Injection, Shenfu Injection, Shenmai Injection, and Shengmai Injection). AMSTAR 2 checklist showed that the methodological quality of the SR/MA ranged from moderate to very low. Item 2(prior study design) was the critical item with poor scores, and the non-critical items with poor scores were items 3(explain the selection of the study designs), items 10(report on the sources of funding), and items 16(conflicts of interest stated). In terms of PRISMA 2020, items in eight topics with complete reporting of missing>50%, including search strategy, certainty assessment, results of syntheses, certainty of evidence, registration and protocol, support, competing interests, availability of data, code and other materials. The included SR/MA involved 30 outcome indicators. Evidence quality of mortality, APACHE Ⅱ, and safety, the top three outcome indicators, was evaluated, and all of them were graded as the medium level. The lack of random allocation sequence, allocation concealment mechanism, blinding, and trial sample size was the main reason for the reduction of the evidence level. The available evidence shows that Chinese herbal injections can serve as an effective and safe adjunctive treatment for sepsis, which can reduce mortality, inhibit inflammation, improve coagulation function, and regulate immune function, tissue perfusion, and oxygenation in patients with sepsis. However, the quality of SR/MA was suboptimal, and more high-quality SR/MA is needed to provide evidence to support the efficacy and safety of Chinese herbal injections in the treatment of sepsis.

Time distribution of positive nucleic acid detection in imported cases infected with SARS-CoV-2 in China / 中华流行病学杂志

Objective: To analyze the time distribution of the first positive nucleic acid detection in imported cases infected with SARS-CoV-2 reported nationwide in China and provide references for further improvement of the prevention and control of COVID-19 in international travelers. Methods: The data of imported cases infected with SARS-CoV-2 reported by provinces from 24 July 2020 and 23 July 2021 were collected for the analysis on the time distribution of the first positive nucleic acid detection after entering China. Results: A total of 7 199 imported cases infected with SARS-CoV-2 were reported in 28 provinces during 24 July 2020 to 23 July 2021. The median interval (Q1, Q3) from the entry to the first positive nucleic acid detection of SARS-CoV-2 was 1 (0, 5) day. The imported cases who had the first positive nucleic acid detections within 14 days and 14 days later after the entry accounted for 95.15% (6 850/7 199) and 4.85% (349/7 199) respectively. Among these cases, 3.65% (263/7 199), 0.88% (63/7 199) and 0.32% (23/7 199) had the first positive nucleic acid detections within 15-21 days, 22-28 days and 28 days later after the entry respectively. The proportion of asymptomatic infections were 47.24% (3 236/6 850) and 63.61% (222/349) among the cases who had the first positive nucleic acid detections within 14 days and 14 days later after the entry respectively. A total of 39.54% (138/349) of cases infected with SARS-CoV-2 with the first positive nucleic acid detections 14 days later after the entry had inter-provincial travel after the discharge of entry point isolation. Conclusions: About 5% of the imported cases infected with SARS-CoV-2 were first positive 14 days later after the entry. In order to effectively reduce the risk of domestic COVID-19 secondary outbreaks caused by imported cases, it is suggested to add a nucleic acid test on 8th -13th day after the entry.