True Cases

My mentor in epidemiology often emphasizes the importance of "remembering the denominator." The denominator in any proportion is crucial; without understanding how it has changed, we cannot truly interpret the numbers.

So, what is the denominator in this context? Typically, our understanding of coronavirus statistics is based on confirmed cases—those who have undergone testing (usually RT-PCR tests) and received positive results confirmed by their respective countries.

This leads to graphs showing a significant increase in cases during the second wave. But we must consider the denominator: how many tests were conducted during the first wave compared to the second?

Consequently, our comparisons can be misleading. Serological studies—testing large populations for antibodies—have revealed that many cases were overlooked during the first wave. For instance, the REACT-2 study in England, one of the most comprehensive serological surveys globally, estimated that 6% of the population had contracted COVID-19 by July, translating to roughly 3.5 million individuals. In contrast, official reports indicated around 350,000 infections, suggesting a potential underestimation by a factor of ten.

Another method to assess true case numbers involves using death rates to back-calculate infections. Although case ascertainment can fluctuate—affecting testing volume and eligibility—deaths serve as a stable metric. Given our understanding of COVID-19's death rate by age, we can estimate the number of cases linked to each death.

For example, examining the graphs for cases and deaths in the United States may initially suggest a 'casedemic,' with cases rising but a smaller increase in deaths.

Yet, by back-calculating from age-specific death data...

...the disparity diminishes. In fact, it appears that the first wave might have been even larger than the second. This observation aligns with the fact that, in the United States, testing was limited during March, primarily focusing on hospitalized patients, leaving many mild cases undetected.

This trend is consistent across various countries when examining serological data. We simply did not capture as many actual cases during the first wave as we do now.

Bottom Line

The central argument behind the 'casedemic' myth is clearly unfounded. It is evident that the actual number of cases earlier in the year was significantly higher than the recorded figures—this is a widely accepted fact. Moreover, many regions are currently experiencing a resurgence akin to what we saw in March.

The unfortunate reality of COVID-19 is that we can fairly accurately predict the trajectory of the disease. An increase in cases typically precedes a rise in hospitalizations, followed by an eventual increase in deaths. This trend is already observable in Europe, where countries like France, Belgium, and the UK are facing a surge of serious cases. Despite improvements in treatment, the mortality rate remains alarmingly high across various age groups.

As more individuals fall ill, it is inevitable that some will succumb to the disease.

This is why countries like Sweden, despite not yet experiencing significant death increases, are implementing new restrictions to mitigate the rising case numbers. Although predicting the number of deaths without knowing the age distribution of cases is challenging, the substantial surge in cases is likely to be followed by a corresponding increase in hospitalizations and deaths.

The notion that a 'casedemic' exists is a misconception; what we face is simply an ongoing pandemic. As unsettling as that truth may be, it is nonetheless the reality we must confront.

In this video, experts discuss the recent surge in severe illnesses in children following COVID-19 infection, shedding light on the ongoing effects of the virus.

This video addresses the transition from pandemic to endemic, exploring how public health responses are adapting to the current situation.

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