Does school shutdown increase inequality in academic performance? Evidence from COVID-19 pandemic in China.

The school shutdown due to the global pandemic of coronavirus disease 2019 (COVID-19) can lead to an increase in educational inequality through disproportionately affecting disadvantaged children. We use data from a unique survey of 7202 junior high school students and their parents from Shaanxi province to explore whether the school shutdown enlarged the educational gap between students with different parental socioeconomic statuses (SES) during the pandemic. We find that students with more highly educated parents experienced an increase in relative test rankings after the shutdown period. A 1-year increase in parents' education led to a relative 0.18-percentile increase in students' rankings of total test scores. We also identify the mechanisms behind the enlarged gap by means of heterogeneity analyses. We show that parents' education mainly affected children's academic performance through parents' engagement in their children's homeschooling, mitigating the negative impacts of Internet addiction on students, and serving as substitutes for teachers who were unable to teach well online.

Short-Term Instantaneous Prophylaxis and Efficient Treatment Against SARS-CoV-2 in hACE2 Mice Conferred by an Intranasal Nanobody (Nb22).

Current COVID-19 vaccines need to take at least one month to complete inoculation and then become effective. Around 51% of the global population is still not fully vaccinated. Instantaneous protection is an unmet need among those who are not fully vaccinated. In addition, breakthrough infections caused by SARS-CoV-2 are widely reported. All these highlight the unmet needing for short-term instantaneous prophylaxis (STIP) in the communities where SARS-CoV-2 is circulating. Previously, we reported nanobodies isolated from an alpaca immunized with the spike protein, exhibiting ultrahigh potency against SARS-CoV-2 and its variants. Herein, we found that Nb22, among our previously reported nanobodies, exhibited ultrapotent neutralization against Delta variant with an IC50 value of 0.41 ng/ml (5.13 pM). Furthermore, the crystal structural analysis revealed that the binding of Nb22 to WH01 and Delta RBDs both effectively blocked the binding of RBD to hACE2. Additionally, intranasal Nb22 exhibited protection against SARS-CoV-2 Delta variant in the post-exposure prophylaxis (PEP) and pre-exposure prophylaxis (PrEP). Of note, intranasal Nb22 also demonstrated high efficacy against SARS-CoV-2 Delta variant in STIP for seven days administered by single dose and exhibited long-lasting retention in the respiratory system for at least one month administered by four doses, providing a strategy of instantaneous short-term prophylaxis against SARS-CoV-2. Thus, ultrahigh potency, long-lasting retention in the respiratory system and stability at room-temperature make the intranasal or inhaled Nb22 to be a potential therapeutic or STIP agent against SARS-CoV-2.