Covid-19: Comparisons by Country and Implications for Future Pandemics (preprint)

Background We set out in this paper to compare Covid-19 results by country to better understand the factors leading to the differing results found internationally. Methods We used publicly available large datasets to explore differences by country for Covid-19 mortality statistics. We continuously challenged our projections with reality and numbers from countries around the world, allowing us to refine our models and better understand the progression of the epidemic. All our predictions and findings were discussed and validated from a clinical viewpoint. Results While no lockdown resulted in higher mortality, the difference between strict lockdown and lax lockdown was not terribly different and favored lax lockdown. Only one of the top 44 countries had long and strict restrictions. Strict restrictions were more common in the worst performing countries in terms of Covid mortality. The United States had both the largest economic growth coupled with the largest rate of mortality. Those who did well economically, had lower mortality and less pressure on their population. Yet they had less mortality than average and less than their neighbors. Conclusions Countries with the least restrictions fared best economically. Some of them fared well in terms of mortality, even better than neighboring countries with similar social structures and more severe restrictions. The mortality rates in the USA, however, appeared to suffer from very high obesity rates. Norway and the northern European countries have less strict restrictions from the rest of Europe and had lower mortality rates. COVID-19 mortality was associated with vitamin D status.

Understanding SARSCOV-2 propagation, impacting factors to derive possible scenarios and simulations (preprint)

We aimed to analyze factors impacting the Covid-19 epidemic on a macro level, comparing multiple countries across the world and verifying the occurrence at a micro level through cluster analysis. The severity of the epidemic was most strongly related to exposure to ultraviolet light and extrapolated levels of vitamin D and to the health of the population, especially with regards to obesity. We found no county with an obesity level < 8% with a severe epidemic. We also found that countries where the population benefited from sun exposure or vitamin D supplementation and spent time outside fared well. Factors related to increased propagation of the virus included the use of heating ventilation and air conditioning (HVAC), population density, poorly aerated gatherings, relative humidity, timely policies of closing clustering places until aeration was improved, and daily amount of ridership on public transportation, especially subways. Population lockdowns, masks, and blood type did not provide much explanatory power. Contact tracing was not analyzed as very few countries applied it for long enough. The excess mortality observed is within the ranges of severe past influenza epidemics of 2016/2017 or 1999/2000 and lower than older severe influenza epidemics of the 1940s or 1970s. We estimated that COVID mortality death counts in European countries is over estimated when taking into account excess mortality further confirming the important role of comorbidities independently of lockdown policy. A few countries observed an under-mortality despite of some deaths counts attributed to COVID-19. Treatments or vaccines should protect the fraction of the population that is not suffering from severe comorbidities. Our study suggested that prevention measures should be directed to improving aeration systems, enhancing diets and exercise, and ensuring adequate levels of vitamin D. Prevention measures and attention should be paid to anxiety resulting from this episode which may be associated with increases in obesity, addictions, vitamin D deficiency, depression, suicide, and hunger ultimately weakening population resiliency.