Since the beginning of the coronavirus pandemic, approximately 435 million individuals have been infected worldwide and 5.9 million people have died from COVID-19 related illnesses (1, 2). At the time of writing, in Israel, approximately 3.6 million people out of a total population of 9.3 million have been infected and over 10,000 people have died of the disease (3). Although COVID-19 was initially considered to be primarily a respiratory disease, it is now evident that the virus may harm the pulmonary, cardiovascular, neurologic, psychiatric, gastrointestinal, renal, endocrine, and musculoskeletal systems, in both adult and pediatric populations (4, 5), and more rarely, in children, can lead to a life threatening multisystem inflammatory syndrome (MIS-C) (6). While the acute symptoms of COVID-19 infection typically remit after several weeks, a concerning proportion of individuals experience lingering symptoms that persist for months after infection (1, 7). Symptoms that appear during or after COVID-19 onset, and which persist for one month or more, are referred variably in the literature as post-COVID, post-COVID syndrome, post-acute COVID, long-haul COVID, or simply, “long-COVID”. There is considerable variability with respect to the presentation of long-COVID: some individuals experience a continuation of the same symptoms as when they were first infected; others may experience an asymptomatic period followed by a recurrence of symptoms; and still others present with symptoms that are different from when they were first infected (7). Symptoms and conditions most commonly associated with long-COVID include shortness of breath and fatigue and may also include dizziness, chest and abdominal pain, and mental health problems such as depression, anxiety, and posttraumatic stress disorder (5, 8–12).

Long-COVID is difficult to diagnose and treat, not only because the disease is still an evolving phenomenon but also as a result of its varied presentation, lack of specificity, and temporal separation from the acute infection. Nevertheless, it can significantly degrade quality of life and wellbeing (13, 14). Moreover, there is growing evidence that long-COVID may be related to underlying damage to major organs including the lungs, heart and cardiovascular system, liver, kidneys, and brain (1). Recently, large population studies have shown that individuals who recovered from COVID-19 have significantly increased risk of incident cardiovascular disease (15), mental health disorders (15, 16), and brain anomalies on MRI (17) even among confirmed cases whose acute infection was mild or asymptomatic. Thus, with millions affected worldwide, and as the world transitions to “living with COVID” (18), understanding the nature and determinants of long-COVID is an increasingly urgent public health concern (19–22).

As we have already learned with respect to acute-COVID, social and economic disparities are among the most important predictors of disease severity and outcome and of willingness to accept public health guidance, including on vaccination. It stands to reason that these factors will also be important in determining the outcomes of long-COVID because of the close relationship between the incidence and severity of the acute disease, with disparities in education and income, food insecurity and obesity, as well as vaccine hesitancy among ethnic minorities and other marginalized populations (22–30). However, little is known about the social and economic determinants of long-COVID. Clarifying their role in this chronic and prevalent condition will be necessary if we are to improve clinical care for this condition and develop effective and equitable public health policies to deal with its consequences.

Although still in infancy, a growing set of studies have examined risk factors associated with long-COVID. Older adults and women have been found to be at a heightened risk for onset (31, 32) as have persons with high body mass and those who had reported more than five symptoms when initially infected (31). Co-morbid health (asthma, obesity) and mental health problems prior to the pandemic have also been linked to the onset of long-COVID (32). In light of these studies, we aimed to identify the socioeconomic and demographic factors associated with the prevalence of self-reported long-COVID symptoms using cross-sectional data obtained from our prospective online survey of a nationally-representative sample of the Israeli population.

This study explored the reported prevalence of COVID-19 long-term symptoms and how these symptoms vary with infection and severity of acute-COVID and by demographic and socioeconomic characteristics. The findings indicated that those infected with COVID-19 and who suffered moderate to severe illness were more likely to both experience long-COVID and to suffer more symptoms than those who experienced minor illness or were not infected at all. These findings align with those of a systematic review that found the severity of initial infection or symptom load is associated with a greater likelihood of long-COVID symptomatology (34), as well as with those of a recent German study which reported the intensity of acute phase symptoms as a predictor of post-COVID syndrome (35). Thus, our results further stress the importance of developing proactive and standardized practices for monitoring post-infection symptomatology to combat long-COVID (36, 37). Furthermore, we found that belonging to low-income and/or to a marginalized social or ethnic group was associated with an even greater likelihood of experiencing long-COVID. Our results are consistent with previous findings identifying specific subgroups as more vulnerable to both acute-COVID (38) and several symptoms of long-COVID (39–41). Additionally, recent evidence indicates higher rates of healthcare utilization (e.g., visits with a primary care provider) in the year following the acute COVID infection among socially vulnerable populations (42), highlighting the potential burden on healthcare facilities and staff among marginalized communities. Notably, in the current analysis, individuals from the high-income group that experienced mild or severe acute-COVID symptomatology also reported relatively high rates of long-term symptoms. This finding may reflect the documented association between income levels and COVID awareness (43) and suggest that the mechanisms involved in experiencing long-COVID are complex and warrant further research. Further discussion of these findings, their clinical and social implications, and future research directions are elaborated on below.

The findings relating to specific population groups that were more susceptible to long-COVID raise interesting health and social issues. Individuals of marginalized groups, whether due to ethnicity, social affiliation, low income, or other reasons, are known to be highly vulnerable in emergencies and to be disproportionately affected by them (44). The increased vulnerability stems from various barriers which impede the access of these groups to a variety of resources such as healthcare (45) and education (46), consequently leading to inequalities and blocking life opportunities (47). The COVID-19 pandemic is a stark and ongoing example of the complex ways in which marginalization materializes in adverse outcomes. In Israel, acute-COVID infections and mortality were higher in communities with predominantly Arab and ultra-Orthodox Jewish populations, which also tend to have lower income rates than the general Jewish population (48). Conversely, vaccination was lower among the same populations, despite access to universal healthcare and the rapid rollout of COVID-19 vaccination in Israel (49). The increased vulnerability of these groups has been attributed to various factors such as crowded living conditions, increased dependency on public transportation, employment in occupations that do not allow for the maintenance of social distancing, and a lack of trust in state institutions and their guidelines (50). Our findings provide the first insights into the association between COVID long-term risks and ethnicity, religiosity, and income levels in Israel. The results highlight ultra-Orthodox and Arab Israelis as also highly vulnerable to long-COVID. However, the low vaccine uptake reported above cannot explain these results as we have controlled for vaccination status in our models. The current findings emphasize the importance of raising awareness of long-COVID among these population groups and of the therapeutic options available to those in need. Awareness efforts should be tailored to these groups and should consider their unique socioeconomic and cultural characteristics as well as their preexisting low access to healthcare services (50). For example, several studies suggest using remote home monitoring to manage post-COVID recovery and rehabilitation using telemedicine platforms and devices (51, 52). However, it should be noted that the rate of telemedicine use among marginalized groups is relatively low (53, 54). Thus, close attention should be paid to ensure that the use of telemedicine in this context does not exacerbate existing inequalities.

The challenges of studying long-COVID are considerable (55). It is difficult to attribute the presence of prevalent, persistent, and diffuse or non-specific symptoms to the initial infection with certainty, particularly in cross-sectional and retrospective studies that are susceptible to recall bias. It is important to obtain a diagnosis of the initial infection and to demonstrate that the post-acute symptoms are sequalae of the infection that did not pre-date it. Thus, prospective studies are needed to identify risk factors for incident long-COVID by comparing exposures and outcomes between cases of long-COVID, acute only cases, and healthy controls. The inclusion of questions pertaining to long-COVID in the ongoing phase of our study will allow us to study incident long-COVID in future waves.

The current study has several limitations. First, the study relies on cross-sectional and self-reported data, which may lead to bias and inaccuracy in estimating the phenomenon under investigation, namely long-COVID. Moreover, it is reasonable to assume that a certain proportion of the participants experienced asymptomatic acute-COVID and were not officially diagnosed (56), which may cause additional bias. However, even if this figure turns out to be accurate, it will strengthen the research findings and not weaken them. Second, the issue of sample selection may also be the cause of potential bias: the rate of participants from Arab Israeli households in the current sample (11%) is slightly lower than their actual rate (15%) (57). However, here as well, our findings suggest that increasing their rate will strengthen the findings rather than weaken them. Finally, the current analysis evaluated the direct effects of marginalization indicators (e.g., belonging to a low-income household, ethnicity, etc.) on long-COVID symptom prevalence but did not measure their potential indirect effect. This important issue remains the goal of future research.

Despite these limitations, the results presented here help broaden our understanding of the relatively understudied phenomenon of long-COVID by offering insights into the attributes and predictors of this phenomenon, as well as specific populations that are at risk of experiencing it. As the pandemic continues for the foreseeable future and as the current surge of morbidity has led to more than 27 million new or recurrent acute-COVID cases in the US alone (7), it is of utmost importance to prepare for the aftermath of the infection. The current findings can serve as the basis for future healthcare planning and as a launchpad for future investigations of researchers and public health officials worldwide into how to better cope with the long-term consequences of the pandemic. Finally, as long-COVID is still a phenomenon that needs to be unraveled, further research is needed to better characterize the disease and its effects and to explore effective treatment and rehabilitative interventions.