As of the Fall of 2020, many countries are still fighting the COVID-19 pandemic. After the painful first massive wave in the Spring, more and more of them are facing the new outbreaks of varying impact. Understanding the mortality pattern associated with such subsequent outbreaks would help governments better prepare and save lives. These secondary outbreaks are still quite new to the scientists as the data have not been sufficient to identify robust trends. By now, US is dealing with the second outbreak of large magnitude and statistically significant analyses are finally possible.
We have analyzed the weekly mortality death counts for various ages in US for the entire COVID-19 pandemic duration. Three somewhat related features involving age at death have been extracted: a) COVID-19 average age at death, b) fraction of deaths at ages 65+, and c) slope of age gradient regression line on the logarithmic scale. It turns out that during the outbreak the mortality age gradient is undergoing the following changes: a) average age at death at the peak is 4-5 years higher than at the lower point; b) fraction of deaths of 65+ is by approximately 10% higher, and c) the higher slope of the age gradient translates into an extra death risk of 5.8% every year. In other words, risks, to which an elderly population is exposed during all phases of the pandemic, rise sharply during and right after the outbreak peaks.