Effect of SARS-CoV-2 infection on IVF/ICSI-ET outcomes: A propensity score-matched cohort study (preprint)

Background: The SARS-CoV-2 virus is continually evolving, and the worldwide epidemic is still ongoing. There is conflicting evidence regarding how SAS-CoV-2 infection affects the outcomes of assisted reproductive technology (ART). The aim of the current study was to investigate whether the outcomes of in vitro fertilization (IVF) treatment were affected during the acute period of SARS-CoV-2 infection or immediately after recovery from COVID-19. Methods: In this retrospective cohort study, SARS-CoV-2-infected couples who underwent IVF treatment at Wuhan Union Hospital within the first three months following the lifting of the pandemic policy in mainland China were propensity-score matched (PSM) to uninfected couples who received IVF during the dynamic COVID-zero policy. Following matching, 358 and 698 patients were assigned to the SARS-CoV-2-infected and uninfected groups, respectively. The laboratory and clinical outcomes of the two groups were compared. Results: The average number of oocytes retrieved, mature oocyte rates, normal fertilization rates, abnormal fertilization rates, and cleavage rates did not differ significantly between the two groups. The blastocyst formation rates were considerably lower in the infected group than in the uninfected group. Stratification by time from SARS-CoV-2 infection to oocyte retrieval (≤ 30, 31-60, 61-90 and ≥90 days) revealed that both blastocyst formation and available blastocyst rates were significantly decreased when oocyte retrieval was performed 31-60 days after SARS-CoV-2 infection. However, after the first embryo transfer cycle, there were no significant differences in the rates of embryo implantation, biochemical pregnancy, clinical pregnancy or early abortion between the two matched cohorts. Conclusion: SARS-CoV-2 infection had no effect on clinical outcomes after the first embryo transfer cycle; however, the blastocyst formation rate was significantly lower in couples who underwent IVF treatment 31-60 days after SARS-CoV-2 infection, indicating that SARS-CoV-2 infection may still impair embryo developmental potential.

Global DSGE Models

We introduce our GDSGE framework and a novel global solution method, called simultaneous transition and policy function iterations (STPFIs), for solving dynamic stochastic general equilibrium models. The framework encompasses many well-known incomplete markets models with highly nonlinear dynamics such as models of financial crises and models with rare disasters including the current COVID-19 pandemic. Using consistency equations, our method is most effective at solving models featuring endogenous state variables with implicit laws of motion such as wealth or consumption shares. Finally, we incorporate this method in an automated and publicly available toolbox that solves many important models in the aforementioned topics, and in many cases, more efficiently and/or accurately than their original algorithms.

Rational development of a combined mRNA vaccine against COVID-19 and influenza (preprint)

As the world continues to experience the COVID-19 pandemic, seasonal influenza remain a cause of severe morbidity and mortality globally. Worse yet, coinfection with SARS-CoV-2 and influenza A virus (IAV) leads to more severe clinical outcomes. The development of a combined vaccine against both COVID-19 and influenza is thus of high priority. Based on our established lipid nanoparticle (LNP)-encapsulated mRNA vaccine platform, we developed and characterized a novel mRNA vaccine encoding the HA antigen of influenza A (H1N1) virus, termed ARIAV. Then, ARIAV was combined with our COVID-19 mRNA vaccine ARCoV, which encodes the receptor binding domain (RBD) of the SARS-CoV-2 S protein, to formulate the final combined vaccine, AR-CoV/IAV. Further characterization demonstrated that immunization with two doses of AR-CoV/IAV elicited robust protective antibodies as well as antigen-specific cellular immune responses against SARS-CoV-2 and IAV. More importantly, AR-CoV/IAV immunization protected mice from coinfection with IAV and the SARS-CoV-2 Alpha and Delta variants. Our results highlight the potential of the LNP-mRNA vaccine platform in preventing COVID-19 and influenza, as well as other respiratory diseases.

Mouse Antibodies with Activity Against the SARS-CoV-2 D614G and B.1.351 Variants (preprint)

With the rapid spread of SARS-CoV-2 variants, including those that are resistant to antibodies authorized for emergency use, it is apparent that new antibodies may be needed to effectively protect patients against more severe disease. Differences between the murine and human antibody repertoires may allow for the isolation of murine monoclonal antibodies that recognize a different or broader range of SARS-CoV-2 variants than the human antibodies that have been characterized so far. We describe mouse antibodies B13 and O24 that demonstrate neutralizing potency against SARS-CoV-2 Wuhan (D614G) and B.1.351 variants. Such murine antibodies may have advantages in protecting against severe symptoms when individuals are exposed to new SARS-CoV-2 variants.

Sex differences and Psychological Stress: Responses to the COVID-19 epidemic in China (preprint)

Background: About 83,000 COVID-19 patients were confirmed in China up to May 2020. Amid the well-documented threats to physical health, the effects of this public health crisis - and the varied efforts to contain its spread - have altered individuals’ “normal” daily functioning. These impacts on social, psychological, and emotional well-being remain relatively unexplored – in particular, the ways in which Chinese men and women experience and respond to potential behavioral stressors. Our study investigated sex differences in psychological stress, emotional reactions, and behavioral responses to COVID-19 and related threats among Chinese residents. Methods: In late February (2020), an anonymous online questionnaire was disseminated via WeChat, a popular social media platform in China. The cross-sectional study utilized a non-probabilistic “snowball” or convenience sampling of residents from various provinces and regions of China. Basic demographic characteristics (e.g., age and gender) – along with residential living arrangements and conditions – were measured along with psychological stress and emotional responses to the COVID-19 pandemic. Results: 3,088 questionnaires were returned: 1,749 females (56.6%) and 1,339 males (43.4%). The mean stress level,as measured by a visual analog scale, was 3.4 (SD=2.4) - but differed significantly by sex. Besides sex, factors positively associated with stress included: age (<45 years), employment (unsteady income, unemployed), risk of infection (exposureto COVID-19，completed medical observation), difficulties encountered (diseases, work/study, financial, mental), and related behaviors (higher desire for COVID-19 knowledge, more time concerning on the COVID-19 outbreak). “Protective” factors included frequent contact with colleagues, calmness of mood comparing with the pre-pandemic, and psychological resilience. Males and females also differed significantly in adapting to current living/working, conditions, responding to run a fever, and needing psychological support services. Conclusions: The self-reported stress of Chinese residents related to the COVID-19 pandemic was significantly related to sex, age, employment, resilience and coping styles. Future responses to such public health threats may wish to provide sex- and/or age-appropriate supports for psychological health and emotional well-being to those at greatest risk of experiencing stress.

Psychological Stress and Gender Differences during COVID-19 Pandemic in Chinese Population (preprint)

About 83000 COVID-19 patients were confirmed in China up to May 2020. The effects of this public health crisis - and the varied efforts to contains its spread - have altered individuals "normal" daily functioning. This impact on social, psychological, and emotional well-being remain relatively unexplored, especially the ways in which Chinese men and women experience and respond to potential behavioral-related stressors. A cross-sectional study was conducted in late February 2020. Demographic characteristics and residential living conditions were measured along with psychological stress and behavior responses to the COVID-19 epidemic. 3088 questionnaires were received: 1749 females (56.6%) and 1339 males (43.4%). The mean level of stress, as measured by a visual analog scale, was 3.4 (SD=2.4) - but differed significantly by sex. Besides sex, factors positively associated with stress included: age ([≤]45 years), employment (unsteady income, unemployed), risk infection population (exposed to COVID-19, completed medical observation), difficulties encountered (diseases, work/study, financial, mental), behaviors(higher desire for COVID-19 knowledge, more time spent on the COVID-19). "Protective" factors included frequently contact with colleagues, calmness, and psychological resilience. Males and females also differed significantly in adapting to current living/working status, coping with heating, and psychological support service needs. Among Chinese, self-reported stress related to the COVID-19 epidemic were significantly related to sex, age, employment, resilience and coping styles. Future responses to such public health threats may wish to provide sex- and/or age-appropriate supports for psychological health and emotional well-being to those at greatest risk of experiencing stress.