ABSTRACT
Both Pfizer-BNT162b2 and Moderna-mRNA-1273 vaccines can elicit an effective immune response against SARS-CoV-2 infection. However, the elicited serum antibody levels vary substantially and longitudinally decrease after vaccination. We examined the correlation of vaccination-induced IgG levels and neutralization titers against newly emerged variants remains and demonstrate a significant reduction of neutralization activities against the variants (B.1.1.7, B.1.525, and B.1.351) in Pfizer or Moderna vaccined sera. There was a significant and positive correlation between serum IgG levels and ID50 titers for not only SARS-CoV-2 WT but also the variants. These findings indicate that a high level of anti-spike IgG may offer better protection against infection from SARS-CoV-2 and its variants. Therefore, it is necessary to longitudinally monitor specific serum IgG level for evaluating the protective efficacy of the vaccines against SARS-CoV-2 and its new variants.
Subject(s)
COVID-19ABSTRACT
We present a compartmental meta-population model for the spread of Covid-19 in India. Our model simulates populations at a district or state level using an epidemiological model that is appropriate to Covid-19. Different districts are connected by a transportation matrix developed using available census data. We introduce uncertainties in the testing rates into the model that takes into account the disparate responses of the different states to the epidemic and also factors in the state of the public healthcare system. Our model allows us to generate qualitative projections of Covid-19 spread in India, and further allows us to investigate the effects of different proposed interventions. By building in heterogeneity at geographical and infrastructural levels and in local responses, our model aims to capture some of the complexity of epidemiological modeling appropriate to a diverse country such as India.
Subject(s)
COVID-19ABSTRACT
Importance The global COVID-19 pandemic, which began in late 2019, has resulted in a renewed focus on the importance of personal protective equipment (PPE) and other interventions to decrease the spread of infectious diseases. While several ophthalmology organizations have recently released guidance on appropriate PPE for surgical procedures and ophthalmology clinics, there is limited experimental evidence demonstrating the efficacy of the various interventions that have been suggested. In this study, we evaluate high-risk aspects of the slit-lamp exam and the effect of various PPE interventions. Objective To determine the effectiveness of surgical masks, slit lamp shields, and gloves in decreasing the spread of large droplets in an ophthalmology clinical setting and evaluating high-risk sources of contamination. Design Experimental cough simulation using a fluorescent surrogate of respiratory droplets during an ophthalmic slit lamp examination. Setting Single-center Participants Patient Simulation Main outcomes and measure(s) Presence of fluorescent particles in the air near or on slit lamp and simulated slit lamp examiner. Results Simulated coughing without a mask or slit lamp shield resulted in widespread dispersion of fluorescent droplets on the model slit lamp examination. Coughing with a mask resulted in the most significant decrease in fluorescent droplets, however, particles were still seen to escape from the top of the mask. Coughing with the slit lamp shield alone blocked the majority of forward particle dispersion; however significant distributions of respiratory droplets were found on the slit lamp joystick as well as table. Coughing with both mask and slit lamp shield resulted in the least dispersion on to the simulated examiner. Scanning electron microscopy demonstrated particle sizes of 3-100μm. Conclusion and relevance Masking has the greatest effect in limiting spread of respiratory droplets, while slit lamp shields, and gloves also contribute to limiting exposure to respiratory droplets from SARS-CoV-2 during slit lamp examination. Key Points Question How effective are certain personal protective equipment and interventions in the clinic in preventing respiratory droplet spread? Findings Simulating patient coughing during the slit lamp exam demonstrated that masking appeared to be the most effective intervention to prevent spread of respiratory droplets. Slit lamp shields and gloves were also effective in decreasing exposure to respiratory droplets. Meaning This study confirms the importance of masking, slit lamp shields, as well as gloves as important interventions to limit exposure to respiratory droplets from respiratory viruses such as SARS-CoV-2.