Seroepidemiology of pertussis in the east of China: Estimates of incidence of infection in adolescents and adults pre- and post-COVID-19.

Introduction: The dramatic decrease in the number of reported cases of pertussis during COVID-19 pandemic has been underestimated. The objective was to compare the estimated incidence rate of pertussis in populations pre- and post-COVID-19 pandemic by analyzing the anti-pertussis toxin (anti-PT) IgG and anti-filamentous hemagglutininant (anti-FHA) IgG antibodies in healthy Chinese population from 2018 to 2021. Methods: All serum samples (N = 1,000) were collected from healthy population (aged ≥ 15 years) who attended an annual monitoring project of antibody levels in Jiangsu province in 2018-2021 were measured by ELISA. Results: The positive rates of anti-PT IgG and anti-FHA IgG antibodies were 11.4% (114/1,000) and 20.2% (202/1,000) (≥40 IU/ml), the GMC were 17.25 (95% CI: 15.49-19.03) IU/mL and 24.94 (95% CI: 22.73-27.16) IU/mL in the study population, respectively. The percentage of participants with anti-PT IgG antibodies higher than 40 IU/mL was 5.20% (11/212) in 2018, 5.5% (19/348) in 2019, 21.2% (46/217) in 2020 and 17.0% (38/223) in 2021, respectively. The non-detectable rate (<5 IU/mL) of anti-PT IgG antibodies was 16.9, 17.7, 28.1, and 37.3% in 2018, 2019, 2020, and 2021, respectively. We assumed that the infection occurred within 58.6 days, and based on the overall proportion (2.9%) of individuals with anti-PT IgG antibody ≥100 IU/ml, the incidence rate (/100) was estimated by the formula to be 18.08 (95% CI: 12.40-26.11). In addition, the estimated incidence of Post-COVID-19 was higher than that of Pre-COVID-19 (36.33/100 vs. 12.84/100), and the difference was statistically significant (p < 0.05). Conclusions: Our results suggest a high rate of under-reporting of pertussis in Jiangsu Province both pre- and post-COVID-19 pandemic, and there are a large number of adults of childbearing age who are susceptible to pertussis. It seems imperative that vaccination of adolescents and adults should be considered for inclusion in vaccination programs.

Impact of the COVID-19 pandemic on clinical trials: a cross-sectional questionnaire study in China.

Background: The number of Chinese clinical trials has continued to grow throughout the coronavirus disease 2019 (COVID-19) pandemic, but we know little about clinical trial team members' perceptions and attitudes toward the impacts of the pandemic. This study aimed to assess the impact of the COVID-19 pandemic on clinical trials in China from the perspective of research staff to provide a deeper understanding and some recommendations for the ongoing and upcoming clinical trials during the pandemic. Methods: A nationwide cross-sectional questionnaire was distributed to respondents throughout mainland China between September 2021 and October 2021. The participants assessed the impact of the COVID-19 pandemic on clinical trials based on a 5-point Likert-type scale, and exploratory factor analysis (EFA) was used to confirm the factor structure. Descriptive statistical analysis and the Mann-Whitney test were used to discover the differences between different groups. Results: A total of 2,393 questionnaires from 272 hospitals were collected in mainland China. Factor analysis resulted in 4 factors, with a cumulative explained variance of 64.93%, as follows: subject enrollment, patient care, study supplies and data management, and research milestones and quality management. The research team members, predominantly represented by clinical research coordinators (CRCs), basically agreed with all but 3 preset scenarios of the impact of COVID-19 on clinical trials. Most respondents did not agree that the pandemic was associated with more serious adverse events (SAEs), missed reports of safety events, or any increase of unscheduled unblinding. In addition, significant differences were revealed in different age, gender, and role groups of respondents based on their views on the impact of the pandemic. Conclusions: The current pandemic situation has had a negative impact on clinical trials, especially in terms of subject recruitment and protocol compliance, yet research team members feel confident that some of the effective measures proposed in the study can moderate the negative impact.

Variations in concentration and solubility of iron in atmospheric fine particles during the COVID-19 pandemic: An example from China.

Iron (Fe) in the atmosphere can affect atmospheric chemical processes and human health. When deposited into oceans, it can further influence phytoplankton growth. These roles of Fe fundamentally depend on its concentration and solubility. However, the sources of aerosol Fe and controlling factors of Fe solubility in megacities remain poorly understood. The outbreak of the COVID-19 pandemic causes large changes in human activities, which provides a unique opportunity to answer these key issues. Field observations were conducted before, during, and after the COVID-19 lockdown in Hangzhou, China. Our results show that in the COVID-19 lockdown stage, the concentrations of total Fe (FeT, 75.0 ng m-3) and soluble Fe (FeS, 5.1 ng m-3) in PM2.5 decreased by 78% and 62%, respectively, compared with those (FeT 344.7 ng m-3, FeS 13.5 ng m-3) in the pre-lockdown stage. The sharp reduction (81%) in on-road vehicles was most responsible for the aerosol Fe decrease. Surprisingly, the Fe solubility increased by a factor of 1.9, from 4.2% in the pre-lockdown stage to 7.8% in the COVID-19 lockdown stage. We found that the atmospheric oxidizing capacity was enhanced after lockdown restrictions were implemented, which promoted the formation of more acidic species and further enhanced the dissolution of aerosol Fe.