COVID-19 is a cause of excessive mortality

Scientists believe that the official coronavirus disease 2019 (COVID-19) infection rate is underestimating the actual number. This is due to the fact that most patients infected with coronavirus disease 2019 (COVID-19) suffer from mild symptoms or are not symptomatic. This group is often ignored when estimating the total COVID-19 cases.

Study: Estimating COVID-19-induced Excess death in Lombardy. Image Credit: joshimerbin/Shutterstock


Complex methods are required to give reliable predictions of the epidemic’s progress; incorrect predictions frequently result in unnecessary panic. In recent times, to better understand the true impact of the COVID-19 pandemic, scientists have examined the mortality rate. Simply put the mortality rate and the impact of severe acute respir coronavirus-2 that is the main cause of this pandemic has been linked. This method has been considered to be the most effective method to assess the global impact of the pandemic. This is due to the fact that mortality reports are more reliable that reports on the number and severity of infections.

A new study has been published in this section of research. It provides an overall linear mixed model that determines the mortality rate caused by COVID-19 infection in Lombardy (Italy). The study is available on the preprint server.

Italy is among the countries that has been severely affected by the ongoing pandemic. Recent research has revealed that Lombardy, a highly industrialized and populated region of Italy is the most affected region, especially during the first wave in the early 2020s and has also experienced a high mortality rate. It is easy to assess the impact of COVID-19 based on the number of deaths.

The difficult process of calculating the high number of deaths caused by COVID-19 can be accomplished by different methods of statistical analysis, from simple averaging methods to a more structured model. Scientists have created a model that can predict excess deaths in Lombardy between 2020 and 2021 and stratified by age groups. The main functions of the linear-mixed model is to detect year-specific inclinations as well as seasonality as well as over-dispersion in deaths due all causes between 2011 to 2019.

Principal conclusions

Research in the past has shown that mortality rates vary according to age. Different models have been employed to analyze the death rate across different age groups. Five age classes were considered in this study: (0-14), (14-64) (65-74) (75-84) and 85+. This model effectively highlights which age group is the most affected by SARS-CoV-2, based on mortality. This can be used to plan preventive strategies to protect the vulnerable sub-populations.

Scientists have identified the prediction intervals using parametric bootstrap. The study found that there was no excess mortality in the youngest age group (0-14 years), and it was not found in 2020 or the first 34 weeks of 2021. This is in line with previous studies which showed that children are not at risk for death from COVID-19 infection.

The highest rate of deaths has been observed in the age range 65-74 and 75-84, with an increase of around 28 percent. Also, in the group comprised of people who are over 85 years old the excess of 25% is estimated. The average age group of working age, 15-64, had an increase of 18% in mortality. The risk of death is directly linked to the age of the individual, as demonstrated by the present study.

The study showed that Lombardy had experienced a large portion of the deaths during the March-April 2020 wave. Additionally, it was determined that people who are over 65 are at greater risk of the COVID-19 pandemic. This prediction is a valid reason to prioritize older people to receive COVID-19 vaccine, as they showed the highest mortality rate both in absolute and relative terms.

This study is limited in terms of access to data and will focus on the first 34 weeks of the study up to August 2021. The mortality rate that is higher for people over 85 years and those between 15 and 64 was not significantly different in the most recent data. However, a significant reduction in the mortality estimate in comparison to 2020, was noted for all other age groups. This data revealed those aged 65-74 and 75-84 are at risk the most currently.

Highlights Highlights

The researchers of this study stated that the positive impact on the reduction in mortality due to excess, owing to the COVID-19 vaccine was determined by comparing mortality rates during the first 34 weeks of 2020 and 2021. In the latter period, a relaxation of non-pharmaceutical treatments was being implemented. A significant reduction in mortality from excess in 2021 has been observed, highlighting the importance of a rapid COVID-19 vaccination.

*Important notice

medRxiv publishes preliminary scientific reports that are not peer-reviewed and, therefore, should not be regarded as conclusive, guide clinical practice/health-related behavior, or treated as established information.

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Gemma Wilson

Gemma is a journalism graduate with keen interest in covering business news – specifically startups. She has as a keen eye for technologies and has predicted quite a few successful startups over the last couple of years.

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