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Updated Findings: Long COVID in the Workers’ Compensation System

October 04, 2023 (8 min read)

By Hon. Susan V. Hamilton, Former Assistant Secretary and Deputy Commissioner, California Workers’ Compensation Appeals Board

A January 2023 issue of the Workers’ Compensation eNewsletter discussed the findings of the Workers’ Compensation Research Institute’s (WCRI) study, “Long COVID in the Workers’ Compensation System Early in the Pandemic” (Bogdan Savych, WC-23-16, January 2023, WCRI) [see LexisNexis article at]. That study, which focused on COVID-19 injury claims during the period March 2020 to September 2020, has been updated using the same methodology as the prior study to examine claims for COVID-19 infections that occurred between March 2020 and September 2021. The updated analysis, Long Covid in the Workers’ Compensation System in 2020 and 2021 (Bogdan Savych, WC-23-31, August 2023) [] includes examination of COVID-19 claims from the period when the Delta variant of SARS C0-V 2 virus was predominant and when vaccines against the virus became widely available. Additionally, it includes 24 months (through March 2022) of medical care and indemnity benefits in the post-acute infection phase. This updated study is especially notable because it corroborates most of the findings from the initial study.

Study Design and Dataset

As a brief reminder of the design and data, the study used workers’ compensation claims data from 31 states that was reported in WCRI’s Benchmark Evaluation database where the injury was identified as a COVID-19 infection, the date of infection was between March 2020 and September 2021, and medical and/or indemnity benefits were paid on the claim. Additionally, the updated study examined post-infection claims records where medical and/or indemnity benefits were paid through March 2022. Consistent with the CDC’s definition of “long COVID” as new, returning, or ongoing symptoms that a patient experiences four or more weeks after being infected with SARS-CoV-2, the study focused its examination on post-acute infection claims records where medical and/or indemnity benefits were paid four weeks or more after the date of infection. The study examined the following questions:

1. What is the prevalence of long COVID among workers with a COVID-19 infection?

2. What are the costs of long COVID claims?

3. What is the duration of temporary disability indemnity benefits among workers with long COVID?

4. What body systems are commonly affected by long COVID and what types of medical services are provided to these workers?

5. What are the industry and worker characteristics associated with long COVID?

6. How do rates of long COVID vary across states?

Question 1: Prevalence of long COVID

Consistent with the initial study, two-thirds of workers with COVID-19 claims received only indemnity benefits and did not receive any medical care. Typically, these workers stayed home from work during the acute phase of the infection, likely managed their relatively minor symptoms with over-the-counter medications, and recovered quickly without any medical intervention. In the initial study, 7% of workers with a COVID-19 infection received care for long COVID symptoms. In the updated study (March 2020-September 2021), 6% of workers with a COVID-19 claim received care for long COVID. The consistency of these findings in the initial and updated studies is further reflected when the type of medical care provided is considered. For example, in both studies, 74% of workers who received ICU treatment in the acute phase (within the first four weeks of infection), also received care for long COVID. Similarly, 44% of workers who were hospitalized without ICU care in the acute phase of the infection received care for long COVID in the initial study as well as in the updated study. Both studies confirm that there is a high correlation between treatment in the ICU in the acute phase of the infection with post-acute treatment for long COVID.

Question 2: Costs of long COVID

The results of both studies demonstrate that long COVID claims tend to be expensive and are far more costly than an ordinary COVID claim. The average medical payment for COVID-19 infection claims that did not develop long COVID was approximately $3,000 in the initial study and $2,285 in the updated study. Yet, the average cost of a long COVID claim was approximately ten times greater—$29,000. Another consistent finding in both studies was that the intensity of medical care provided during the acute phase of the infection greatly increased the cost of the claim. For example, the average medical cost per claim if the patient was hospitalized in the acute phase was $50,000 in the initial study and $66,000 in the updated study. Moreover, when the patient received ICU care during the acute phase of the infection, the average medical cost was $150,000 in the initial study and $190,000 in the updated study.

Question 3: Costs and Duration of Temporary Disability Among Workers with long COVID

Not surprisingly, the updated study reveals that average indemnity benefits for long COVID claims were significantly higher ($14,000 on average) when compared to a claim without long COVID ($2,000). Workers with long COVID had an average of five months of temporary disability benefits within an 18-month period post-acute infection, compared to an average of two and one-half weeks for claims without long COVID. These findings confirm the initial study’s prediction that long COVID may have a significant impact on a workers’ ability to work after the infection.

Question 4: Body Systems Commonly Affected by long COVID and Types of Medical Services Provided

The updated study results corroborate the initial study findings with negligible difference between the results both as to body systems commonly affected by long COVID and the types of medical services provided to treat the infection. Sixty-four percent of long COVID claims involved the lungs (63% in the initial study), 33% of long COVID claims involved the heart (29% in the initial study), and 12% of long COVID claims affected mental health (10% in the initial study). Similarly, in both the initial and updated studies, 50% of long COVID claims affected multiple body systems.

The most common type of medical service provided to long COVID claimants was office visits to evaluate and manage symptoms. Eighty-two percent of long COVID claimants were treated with office visits (80% in the initial study). The next most common type of treatment received by approximately 33% of long COVID claimants in both studies was laboratory services, radiology services and prescriptive medications. Although only 3% of long COVID claimants were hospitalized in the post-acute period, those services represented 22% of medical payments.

Question 5: Industry and Worker Characteristics Associated with long COVID

The initial and updated study results were identical regarding the likelihood of developing long COVID based on gender. Among all COVID-19 claims, women had a 6% chance of developing long COVID whereas men had a 7% chance. However, among COVID-19 claims where the claimant received medical care, 21% of women developed long COVID versus 16% of men. Both studies report that these findings suggest that sample selection variables may affect the results.

How a worker’s age might impact the development of long COVID was another factor examined. Both studies demonstrated that the age of the worker is a significant factor. In the initial and updated studies, 2% to 4% of workers under the age of 35 developed long COVID. However, 10% to 12% of workers 55 years and older developed long COVID.          

Similarly, the question as to how geographic factors might influence the probability of developing long COVID produced consistent results between both studies. When the researchers examined the universe of all COVID-19 claims, there was only negligible difference in the possibility of developing long COVID between claimants who lived in metropolitan areas with those who lived in rural areas. Yet, when that universe was narrowed to COVID claims with medical treatment in the acute phase of the infection, workers who lived in more rural settings were more likely to develop long COVID than their metropolitan counterparts.

To discern any differences based on the type of industry, both studies examined the following occupations: facility living establishments (i.e., assisted living facilities), hospitals, physician and dental offices, non-medical clerical and professional, food service, trade, manufacturing, construction, and other. The prevalence rate of long COVID among these industries ranged between 4% and 12%, with hospitals at 9% and manufacturing and construction at 12% being on the high end. Interestingly food service was a “low end” outlier with its workers having a long COVID prevalence rate of 2%. The studies posit that one explanation might be the relatively low age of food service workers in comparison to other industries.

Question 6: Variation in long COVID Prevalence Rates Among States

The prevalence rates for workers developing long COVID were between 2% and 8% for all but 2 of the 31 states included in the studies. The two “outliers,” California and Oregon, had long COVID prevalence rates of 10%. One factor that might explain the variations seen between the states is the timing of and exposure to the virus. The northeastern states were the first to be exposed to the virus whereas other states did not see waves of the virus until much later.

Conclusions from the Studies

The initial and updated studies confirm that most workers who were infected with COVID-19 experienced mild symptoms and recovered with little or no medical treatment. The age of the worker at the time of infection and whether the worker received medical treatment, especially in a hospital setting during the acute phase of the infection, substantially increased the likelihood of developing long COVID. The studies also confirm that long COVID claims are a significant driver of medical costs and indemnity benefits. The results of both studies also highlight areas in which additional research will benefit policy makers and stakeholders. For example, the updated study recommends further research and analysis to understand the prevalence of long COVID in subsequent waves of the infection and to better understand the long-term disability implications of long COVID. As we head into what is expected to be a new season of COVID, it seems a certainty that additional research will soon be underway.

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