The Role of Mobility in the Dynamics of the COVID-19 Epidemic in Andalusia.

Metapopulation models have been a popular tool for the study of epidemic spread over a network of highly populated nodes (cities, provinces, countries) and have been extensively used in the context of the ongoing COVID-19 pandemic. In the present work, we revisit such a model, bearing a particular case example in mind, namely that of the region of Andalusia in Spain during the period of the summer-fall of 2020 (i.e., between the first and second pandemic waves). Our aim is to consider the possibility of incorporation of mobility across the province nodes focusing on mobile-phone time-dependent data, but also discussing the comparison for our case example with a gravity model, as well as with the dynamics in the absence of mobility. Our main finding is that mobility is key toward a quantitative understanding of the emergence of the second wave of the pandemic and that the most accurate way to capture it involves dynamic (rather than static) inclusion of time-dependent mobility matrices based on cell-phone data. Alternatives bearing no mobility are unable to capture the trends revealed by the data in the context of the metapopulation model considered herein.

ANTIBODY RESPONSE TO COVID-19 VACCINATION IN PATIENTS UNDER DIALYSIS

BACKGROUND AND AIMS: Patients (pts) with end-stage kidney disease (ESRD) may be more vulnerable to infections and may have a suboptimal response to vaccination. Dialysis patient (pt) began to be vaccinated against COVID-19 in February 2021. However, there were many doubts about whether immunization would be effective for them, as these pts have an impaired immune system, and it seems that this population responds poorly to vaccinations. Serum neutralizing antibodies (AbN) rapidly appear after the SARS-CoV-2 infection and the vaccination and are maintained for several months. The emergence of SARS-CoV-2 variants has raised concerns about the breadth of the neutralizing antibody responses. METHOD: Serum samples were obtained from 181 patients receiving dialysis. Levels of circulating SARS-CoV-2 anti-spike IgG(S) and anti-nucleocapsid IgG (N) antibodies were quantified using the Abbott Diagnostics SARS-CoV-2 IgG chemiluminescent microparticle immunoassay (Abbott Diagnostics, Abbott Park, IL, USA) on an Abbott Diagnostics Architect i2000 SR and an Alinity analyzer, according to the manufacturer's instructions. Serum neutralizing antibodies (AbN) by commercially available assays (cPass SARS-CoV-2 Neutralization Antibody Detection Kit), at the first and the third months after the vaccination, were identified. RESULTS: The IgG-spike Abs had a statistically significant decrease at 3 months after the vaccination in relation to the measurements 1 month after that. AbN had a statistically significant decline at 3 months after the vaccination in relation to the measurements 1 month after. Pts with cardiovascular disease (CD) had significantly lower levels of antibodies than those who did not have CD. Additionally, CD was an aggravating factor in combination with the other comorbidities for the development of antibodies. Pts with a history of malignancy had significantly lower levels of antibodies in relation to those who did not. Those under therapy with antihistamines in the 1st month after the vaccination presented a statistically lower level of the AbNs, but this difference did not exist in the measurements 3 months after vaccination. There was a correlation between the AbNs and the age, also between the time these patients underwent dialysis. Those who had COVID-19 infection presented higher levels of the antibodies AbN/IgG-spiked Ab at 3 months. CONCLUSION: It is presented that the IgG-spike Abs and the AbN had a statistically significant decrease at 3 months after the vaccination, which shows the importance of completing vaccination with the third dose after 3 months. Also, it is presented that CD is a risk factor for lower levels of Abs. Randomized clinical trials for COVID-19 vaccines included a few patients with kidney disease;therefore, the vaccine immunogenicity is uncertain in this population.