Influenza vs COVID admissions in Denmark
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For the past two years many governments around the world - in an attempt to `move beyond the pandemic' - have minimized the ongoing impacts of COVID by ending surveillance and the reporting of numbers of associated hospitalizations or deaths.
As a result, many people now regard COVID infection as `no worse' than influenza.
A worrisome side effect has been that COVID Vaccine uptake has fallen dramatically, despite the litany of scientific reports suggesting the risk of long-term sequelae in a significant percentage of people.
EID Journal: Estimates of Incidence and Predictors of Fatiguing Illness after SARS-CoV-2 Infection
The Lancet: Long-term Outcomes Following Hospital Admission for COVID-19 Versus Seasonal Influenza
The Lancet: Neurological and Psychiatric Risk Trajectories After SARS-CoV-2 Infection
MMWR: Post–COVID-19 Symptoms and Conditions Among Children and Adolescents
Denmark, which has a relatively small population (< 6 million) and a highly sophisticated national health system, continues to track COVID (and other respiratory diseases) aggressively via their SSI (Statens Serum Institut).
Late last week researchers published a preprint showing over the past two years, the burden of COVID on Danish Health continues to far outpace influenza. First, a link to and the abstract from the preprint, followed by a (translated) summary of their findings by the SSI.
The post-pandemic hospital and mortality burden of COVID-19 compared with influenza: A national cohort study in Denmark, May 2022 to June 2024
Peter Bager, Ingrid Bech Svalgaard, Frederikke Kristensen Lomholt, Hanne-Dorthe Emborg, Lasse Engbo Christiansen, Bolette Soborg, Anders Hviid, Lasse Skafte Vestergaard
doi: https://doi.org/10.1101/2024.09.26.24314428
000010129
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Abstract
Background: In the post-pandemic period, COVID-19 continues to cause significant numbers of hospitalisations and deaths. We describe this burden and compare it to the burden of influenza in the first two post-pandemic years in Denmark.Methods: A cohort study including residents in Denmark from May 16, 2022, to June 7, 2024. Data were obtained from national registries, including information on Polymerase chain reaction (PCR) test-positive COVID-19 and influenza admissions, mortality within 30 days of admission, sex, age, COVID-19 and influenza vaccination, comorbidity, and living in long-term care facility for elderly. Negative binomial regression was used to estimate adjusted incidence rate ratios (aIRRs) to compare rates of admissions between COVID-19 and influenza. To assess severity of COVID-19 among hospitalized patients, we used Cox proportional hazard models to estimate adjusted hazard ratios (aHR) of 30-day mortality between COVID-19 and influenza.Results: Among 5,899,170 individuals, admissions with COVID-19 (n=24,687) were more frequent than admissions with influenza (n=8,682; aIRR 2.01, 95%CI 1.37-2.95), in particular during the first year (p=0.01), in the summer (p<0.001) and among people above 65 years of age (p<0.001). The number of deaths were also higher (COVID-19, n=2,393; influenza, n=522). Among patients, the risk of mortality of COVID-19 was higher than influenza in the 12-30 days following admission (0-11 days, aHR 1.08, 95%CI 0.94-1.25; 12-30 days, aHR 1.50, 95%CI 1.21-1.84), in particular among non-vaccinated for both COVID-19 and influenza (aHR 1.81, 95%CI 1.25-2.62), while it was similar to influenza among patients without comorbidities (aHR 1.07, 95%CI 0.63-1.80).Conclusion: COVID-19 represented a greater disease burden than influenza, with more hospitalisations and deaths, and more severe disease primarily among non-vaccinated and comorbid patients. These results highlight the continued need for attention and public health efforts to mitigate the impact of SARS-CoV-2.
The SSI Summary follows.
Covid-19 is still more serious than the flu
Statens Serum Institut demonstrates that covid-19 has been associated with more than twice as many hospitalizations and deaths compared to influenza.Last edited on September 30, 2024
A new study from the Statens Serum Institut (SSI) compares the disease burden of covid-19 and influenza in the first two years after the pandemic, covering the seasons 2022-23 and 2023-24. The study shows that covid-19 has been related to more than twice as many hospitalizations and deaths compared to influenza.
In virtually the entire period, there were several hospitalizations and deaths associated with covid-19. The differences were particularly large in the first year after the pandemic. In addition, it was special for covid-19 that there were not only hospitalizations in the winter, but also in the summer, when influenza is a rare burden. The study also shows that hospitalization for covid-19 in winter was more serious than hospitalization for influenza.
The study included the entire Danish population, including 24,687 people who were hospitalized for covid-19, and 8,682 who were hospitalized for influenza between May 2022 and June 2024. The study takes into account whether there were differences in the two groups in age, gender, vaccination against covid-19 or influenza, region of residence, underlying illness and in nursing home status for the elderly. Covid-19 and influenza patients were defined as those with a positive PCR test for the virus up to 14 days before and up to 2 days after an admission, while the CPR record was used to identify those patients who died within 30 days after the admission.
Vaccination matters
Based on the study, it is difficult to determine whether covid-19 is on its way to becoming a less serious disease burden.
The number of covid-19 hospitalizations fell from 2022-2023 to 2023-2024 in Denmark and in several other comparable countries, including the other Nordic countries and the USA. On the other hand, the covid-19 monitoring in the waste water indicates that high levels of infection continue to occur, especially in autumn and winter.
"A straightforward explanation for the drop in admissions despite the high level of infection is that people at risk of a serious course of covid-19 are vaccinated against serious disease through the annual covid-19 vaccination programme. In addition, there is generally better protection in the population than what we saw at the start of the pandemic, as the majority have either received a vaccination earlier or have been ill with covid-19," says senior researcher and PhD. Peter Bager from SSI's Department of Epidemiological Research, and continues:
"The study supports the importance of the autumn covid-19 vaccination against serious illness, as covid-19, compared to influenza, still poses a significant burden both in terms of hospitalizations and deaths. The results can also contribute to the planning of the health service's covid-19 strategy."
The study focused on hospitalizations and mortality, but it is also important to recognize the burden from e.g. sickness absence due to covid-19 and late effects of covid-19, points out Peter Bager.
The study has been submitted for peer-review in a scientific journal, and can be read as a preprint.
