As the number of COVID-19 deaths worldwide surpasses one million and continues to climb, the real number could be much higher due to misclassified and indirect deaths.
At the beginning of the pandemic, information about rates of infection, hospitalisation and even deaths was often delayed or unreliable. Testing was not widely in place and the understanding of the biological and clinical features of the virus made classifying a ‘COVID death’ difficult.
As many countries are facing a second wave of COVID-19, monitoring has also entered a new phase with more robust data and better reporting systems. However, there are still many cases that may slip through the cracks.
“We will never know the exact number of COVID-19 deaths simply because many patients will never be tested, even though they die from COVID-19,” says Dr Lasse Vestergaard.
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Vestergaard is a medical doctor and epidemiologist who coordinates EuroMOMO, which provides real-time mortality monitoring for 26 European countries. “With the estimation of excess deaths, however, we have a quite precise picture of the total mortality burden from COVID-19 and how it affects different populations,” he adds.
So how do you calculate the toll of the COVID-19 pandemic? One method is by looking at ‘excess deaths’. Networks like EuroMOMO collect data on the number of people who have died from all causes and compare that to the average number for previous years.
The difference in deaths is considered ‘excess deaths’ and gives a better measure of how many people actually died during the pandemic. Excess deaths have been used in the past to measure the impact of swine flu, seasonal influenza and natural disasters.
In a recent paper published in Nature Medicine, researchers looking at 19 countries in central and western Europe, Australia and New Zealand, found that more than 200,000 additional people died in the first wave, when compared to how many deaths would be expected without a pandemic. The death rate was about 30 to 45 per cent higher than average in the hardest hit countries – England and Spain.
A separate report published in the journal JAMA showed there were 225,000 excess deaths in the United States between March and July. Of those, about two-thirds could be explained by COVID-19, which left 75,000 deaths unaccounted for. While the numbers vary between countries, there is often a significant gap that remains.
There are many people who are victims of COVID-19 even if the virus is not what ultimately kills them. COVID-19 puts a significant strain on health services and many people could die of chronic diseases when they would not have otherwise, explains Magali Barbieri, associate director of the Human Mortality Database.
These patients may succumb to a disease early because they were weakened by an infection, hospitals were too full or they chose to delay treatment.
In a paper published in the medical journal The Lancet, researchers forecasted that disruptions to HIV, tuberculosis, and malaria programmes in low- and middle-income countries could have an effect comparable to direct COVID-19 deaths over the next five years.
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Barbieri notes there are also more indirect effects related to ‘the social and economic fallout’ of COVID-19. In the United States, there have been reports of an increase in opioid-related deaths over the last year which, she says, could be related to people feeling too isolated or a lack of resources. Economic hardship could potentially lead to indirect deaths from a number of causes such as addiction or people not being to access the help they need, especially in countries without universal healthcare.
It’s too early to tell what the true toll of the pandemic will be from both direct and indirect deaths. While current reporting systems can give a real-time picture of deaths, it may take years to accurately analyse COVID-related deaths. The ‘gold standard’ is to use data from the vital statistics system in each country which has a detailed breakdown of cause of death and contributing factors, but this information may not be processed on a global scale until 2022.
Why is it important to count deaths?
Researchers and health officials have moved quickly to improve reporting systems and decrease the delay in data. These real-time monitoring systems helped to expose weaknesses in the healthcare system, assess the effectiveness of COVID-19 interventions and could help detect the next public health crisis.
Counting deaths can be morbid, but it’s also hopeful, says Dr Steven Woolf, a professor of family medicine and population health at Virginia Commonwealth University who authored the JAMA paper on excess deaths in the US. For Woolf, how policymakers act on COVID-19 death data today will determine how the next chapter of the pandemic unfolds.
“We have examples of countries, and specific states [in the US], that have demonstrated an ability to bend the curve and get the numbers back to normal,” he says. “States that took this more robust response had a much more successful story.”