Monday, April 03, 2023

SSI Preprint: Extended Sick Leave Following COVID Infection (Long COVID)


While there are hopeful signs that the COVID emergency may be nearing an end, we've seen a steady stream of studies showing that COVID infection - and particularly reinfection (even when the resulting illness is mild) -  can lead to serious, even debilitating, sequelae.

A few recent blogs on this topic include:

EID Journal: Postacute Sequelae of SARS-CoV-2 in University Setting

NIH Preprint: Comparing The Impact Of `Long Flu' to `Long COVID'

JAMA: Persistent COVID-19 Symptoms at 6 Months After Onset and the Role of Vaccination Before or After SARS-CoV-2 Infection

While many of these `Long COVID' symptoms are relatively mild, and resolve over a period of weeks or months, Post-COVID sequelae can also include far more serious cardiovascular, renal, pulmonary, neurological, and endocrine disorders.

Neurology: Incidence of Epilepsy and Seizures Over the First 6 Months After a COVID-19 Diagnosis: A Retrospective Cohort Study

Last January the AMA released a statement (see What doctors wish patients knew about COVID-19 reinfection) calling reinfection `problematic' and equating it to `. . . playing Russian roulette" with the virus. 

While most people who are infected (or reinfected) with COVID won't develop serious sequelae, right now we don't know how big the impact will become over time.  

Denmark - due to having one of the best monitored health-care delivery systems in the world - is a very good place to look for answers.

Today Denmark's SSI has published a summary of a recent preprint, which found a steep (3-fold) increase in taking extended sick leave (> 30 days) among those who had `recovered' from COVID , compared to those who have not been infected. 

Increased sickness absence for a long time after covid-19 infection

Those who were infected with covid-19 early in the pandemic have, for a long time after the infection, had significantly more sick leave than those who were not infected, shows a study from the Statens Serum Institut.
Last edited on April 3, 2023

Late effects of covid-19 have affected many. For some, the late effects have been mild and transient, while for others they have been severe and debilitating. But how big of a burden has latecomers been – for the individual and for society? A new study from the Statens Serum Institut (SSI) provides an answer.

The study has examined sickness absence, as it can provide a clue as to how serious the late effects of those infected have been. And the conclusion is clear: A large number of previously infected people have had significant sickness absence for a long time after infection.
Not mild

The study, which is part of the large follow-up study AFTER-Covid and is based on data on sickness absence from 88,818 Danes, has investigated how much sickness absence those infected with covid-19 experienced in a period of eight months after the acute phase of the infection was over. The researchers then compared these figures with sickness absence in people who were not infected. Among those previously infected, it was 4.5 percent who had more than four weeks of sick leave during the study period. The corresponding figure for non-infected people was only 1.4 percent.

"It puts a clear line under the fact that late sequelae were not mild and transient for the vast majority of people, as many probably hoped early in the pandemic", says professor and head of department Anders Hviid, who led the study and continues:

"In the current study, we are looking at Danes who were infected between November 2020 and February 2021. Since we see fewer late effects after vaccination and infection with the omicron variant, we also expect that there will be less sick leave associated with infection later in the pandemic".
Who was most exposed

The researchers also investigated which groups had the most sickness absence associated with previous infection. Here it was clear that there were big differences. Women, the elderly and severely obese had more sickness absence than men, younger and of normal weight. In addition, it also played a significant role whether you had chronic diseases before you became infected. People with fibromyalgia, diabetes and lung disease appeared to be particularly hard hit.

The link to the preprint follows:

Covid-19 and post-acute sick leave: a hybrid register and questionnaire study in the adult Danish population

Elisabeth O'Regan, Ingrid Bech Svaalgard, Anna Irene Vedel Soerensen, Lampros Spiliopoulos, Peter Bager, Nete Munk Nielsen, Joergen Vinsloev Hansen, Anders Koch, Steen Ethelberg, eAnders Hviid

This article is a preprint and has not been certified by peer review [what does this mean?]. 

Preview PDF

After three exhausting years of COVID, there is an understandable desire to want to declare victory, downgrade COVID to being a seasonal `flu-like illness', and move on with life. But evidence continues to show that COVID infection (and particularly reinfection) - carries some long-term health risks. 

Hopefully, between a `milder' Omicron virus, and yearly booster vaccines, the worst of this Post-COVID legacy has passed. 
But Omicron may not be the last wave we will deal with, and some sequelae may take years to become apparent (see Review Article: Parkinsonism as a Third Wave of the COVID-19 Pandemic?). 

Regardless of what happens with our current pandemic emergency, we probably won't know the full impact of `Long COVID' on society for another 5 or 10 years. 

For more on the impact of Long COVID, you may wish to revisit these CDC webinars:
COCA Call: Evaluating and Supporting Children and Adolescents Presenting with Post-COVID Conditions

COCA Call : Multisystem Inflammatory Syndrome in Children (MIS-C) - Epidemiology, Case Definition, and Prevention

COCA Call : Evaluating and Supporting Patients Presenting with Cardiovascular Symptoms Following COVID