Since the early 1990s, nanotechnology has led to new horizons in nanomedicine, which encompasses all spheres of science including chemistry, material science, biology, and biotechnology. Emerging viral infections are creating severe hazards to public health worldwide, recently, COVID-19 has caused mass human casualties with significant economic impacts. Interestingly, silver nanoparticles (AgNPs) exhibited the potential to destroy viruses, bacteria, and fungi using various methods. However, developing safe and effective antiviral drugs is challenging, as viruses use host cells for replication. Designing drugs that do not harm host cells while targeting viruses is complicated. In recent years, the impact of AgNPs on viruses has been evaluated. Here, we discuss the potential role of silver nanoparticles as antiviral agents. In this review, we focus on the properties of AgNPs such as their characterization methods, antiviral activity, mechanisms, applications, and toxicity.

Background The coronavirus disease 2019 (COVID-19) pandemic is a worldwide epidemiological emergency, and the risk factors for the multiple waves with new COVID-19 strains are concerning. This study aims to identify the most significant risk factors for spreading COVID-19 to help policymakers take early measures for the next waves. Methods We conducted the study on randomly selected 29 countries where the pandemic had a downward trend in the daily active cases curve as of June 10, 2020. We investigated the association with the standardized spreading index and demographical, environmental, socioeconomic, and government intervention. To standardize the spreading index, we accounted for the number of tests and the timeline bias. Furthermore, we performed multiple linear regression to identify the relative importance of the variables. Results In the correlation analysis, air pollution, PM 2.5 (r = 0.37, p = 0.0466), number of days to impose lockdown from first case (r = 0.38, p = 0.0424) and total confirmed cases on the first lockdown (r = 0.61, p = 0.0004) were associated with outcome measures. In the adjusted model, air pollution ( = 4.5, p = 0.0127, |t| = 3.1) and overweight prevalence ( = 4.7, p = 0.0187, |t| = 2.9) were the most significant exposure variable for spreading of COVID-19. Conclusion Our findings showed that countries with larger PM 2.5 values and comparatively more overweight populations are at higher risk of spreading COVID-19. Proper preventive measures may reduce the spreading.

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