Frederico Guanais is Deputy Head of the OECD Health Division, where since 2019 he has led work on patient-reported indicators, health statistics, people-centred care, climate and health, support to health reforms, and regional initiatives in Latin America. The ESMH spoke with him ahead of the STOA workshop “Long Covid: Current Realities, Future Directions” where he will be one of the main speakers.
How would you describe what Long Covid is in simple words?
Frederico Guanais: In very simple terms, Long Covid is a group of symptoms that persist for more than three months after a COVID-19 infection. Basically, it means that people get COVID-19 but do not fully recover afterwards, and then symptoms persist over time. They can affect various organs and range from mild to severe, becoming very debilitating and even disabling for those who experience them. I could also say that Long Covid is quite common in the population. Some studies estimate that between 5 and 10% of the overall population experiences Long Covid. These studies have been conducted in Scotland, the United States, and across OECD countries.
Here at the OECD, we are fortunate to use a survey called the PaRIS survey, the Patient-Reported Indicator Survey, which included questions on Long Covid in its first wave. The purpose of this survey was to assess health systems performance for patients with chronic conditions, and not specifically to study Long Covid. But because we are already engaging with 107,000 people aged 45 and older in 19 countries who used primary care in 2023, we included questions on Long Covid. We found that 7% of the PaRIS population aged 45 and older haveLong Covid, and 5% were still experiencing symptoms at the time of the interview. This results from a large scale international survey confirmed that Long Covid is indeed a major problem.
Why is Long Covid often referred to as an “invisible illness”, and what are its implications in day-to-day life?
Frederico Guanais: While it is a long-term consequence of the COVID-19 pandemic, it’s much less discussed than the deaths, hospitalisations, and severe infections caused by the pandemic. However, it’s persistent, so that’s one thing we need to recognise: it lingers, and it remains an ongoing problem for those affected by it. I think building the evidence base for Long Covid has taken time; it’s something that requires many studies and cannot be done instantly. Even gaining recognition and a diagnosis of the syndrome has been a challenge. ‘What exactly is Long Covid? How do you detect it? How do you diagnose it?’ Over time, the evidence base has been slowly developing around these questions.
Initially, health systems were not equipped to handle these challenges. It’s also fair to say that the exact mechanisms and causes of the condition are not fully understood, and many hypotheses are currently being discussed. In simple terms, Long Covid doesn’t fit neatly into a single category because it can affect one or more organs. So far, there is no specific biological marker that allows us to develop a definitive diagnostic test. So, it’s not like the detection of the COVID-19 infection itself, where you actually have biological tests to detect it. That is a challenge. It also means that people with Long Covid usually take a long time to get an accurate diagnosis. They can go from doctor to doctor with complaints before knowing they have Long Covid, thus navigating the disease can be quite a challenge for them, as the healthcare system isn’t fully prepared to meet the needs of this population.
Regarding implications, it’s clear that Long Covid has a significant impact on the physical and mental health of those affected, as well as their personal and professional lives. From the PaRIS survey, we have substantial data showing how those with Long Covid struggle to navigate the healthcare system to obtain proper diagnoses. They are generally more likely to have to repeat information during interactions with providers and tend to trust the healthcare system less than those without Long Covid.
What are the main impacts of Long Covid across OECD countries, and what measures can be taken to address them?
Frederico Guanais: On a personal level, some of the negative impacts can include fatigue, particularly crippling and very intense fatigue, exercise intolerance, disturbed sleep, lack of concentration, and memory problems, for example. These are factors that affect your quality of life and well-being, as well as your productivity at work and school. They influence your ability to function. According to the data from the PaRIS survey, one in five patients with Long Covid reported severe fatigue that prevents them from being functional, right, from engaging in daily activities, compared to only one in ten overall patients in the PaRIS survey.
The consequences of that can range from reduced productivity to people being less able to participate in future full-time employment. They’re less likely to attain or pursue educational, school, university activities, and so on. There are also wider social impacts and both direct and indirect costs involved. These are people who are likely to leave the labour force, request sick leave, or seek disability insurance. From the PaRIS survey data, we found that, again, one in eight people with Long Covid were unemployed or on sick leave. This highlights the difficulty of re-entering the workforce. This is a topic where we aim to model the burden of Long Covid to obtain a clearer estimate of its economic costs in OECD countries, both individually and in aggregate. This includes direct health care costs, since affected individuals will typically require more health services than others, as well as indirect costs such as loss of productivity and increased social welfare expenditure. These costs stem from symptoms I mentioned earlier, crippling fatigue, exercise intolerance, disturbed sleep, lack of concentration, and memory problems, which all limit and prevent individuals from being active participants in the workforce, pursuing academic pursuits, or maintaining overall well-being and quality of life.
Finally, due to the difficulty of diagnosis and the lack of a uniform standard and recognition of what constitutes Long Covid, policies are not well-designed to meet the needs of this specific population. In most OECD countries, there are sick leave and unemployment benefits, but not policies specifically designed for the Long Covid group. The first step is to accurately diagnose their needs and develop tailored services accordingly. I believe we are somewhat behind in developing policies that are specifically tailored to this condition. Additionally, the visibility of the condition relates to explaining why there are many unmet needs among the Long Covid population.
What are the main challenges healthcare professionals face in diagnosing and treating Long Covid?
Frederico Guanais: So, firstly, awareness and understanding are essential. As I mentioned, there is no specific test to diagnose Long Covid, which makes it a challenge for healthcare professionals. They must rule out other common conditions before diagnosing Long Covid, but there are no distinct signs. As I said, Long Covid presents differently in various individuals, affecting different organs, but it is a syndrome—essentially a collection of symptoms. This makes diagnosis difficult. Additionally, healthcare professionals are often not adequately prepared for this. Another point is that Long Covid can develop in someone who had very mild or even asymptomatic Covid. Typically, professionals might not look for it because the person never displayed COVID-19 symptoms nor complained about it initially, yet now they have a group of symptoms compatible with Long Covid.
We are working with the WHO Academy to develop a training course aimed at improving healthcare professionals’ ability to diagnose, manage, and communicate about Long Covid. I believe this is a challenge; healthcare professionals need better tools to diagnose cases effectively. Regarding policies, we aim to develop a stronger evidence base through a policy survey. With support from the European Commission, we are completing a Long Covid health policy survey to map out the approaches used by different countries in diagnostics, management, and coordination. Our goal is to learn from each country’s experiences, identify best practices, and see which nations are performing better in detecting and managing Long Covid. Ultimately, we want to develop policy tools that can be shared with healthcare professionals.
Women appear disproportionately affected, particularly those in midlife. How do you explain this gendered pattern?
Frederico Guanais: The highest prevalence of Long Covid is found among middle-aged women, and women in general are 40 to 50% more likely than men to experience Long Covid. So, women are disproportionately affected. However, this doesn’t mean that only women are affected; both men and women of all ages, including children, can experience Long Covid. The increased risk is particularly notable among women, especially middle-aged women. There are potential epidemiological and biological reasons for this. For example, having an existing chronic condition is the strongest risk factor for Long Covid. If you already had a chronic condition before contracting COVID, it increases your chances of developing Long Covid. Chronic conditions, particularly inflammatory and autoimmune ones, are more common among women than men, and the risk increases with age. This partly explains why women tend to develop more severe cases of Long Covid.
One social explanation is that women are more likely to work in healthcare and social care, so they may have been at greater risk of COVID-19, especially during the pandemic’s first waves, when the risk of Long Covid was highest from the original SARS-CoV-2 strain. So, both biological and social epidemiological factors contribute to this. Moreover, older male patients were probably less likely to have survived the initial COVID-19 illness, which may lead to a reporting bias- something known as survival bias. These hypotheses might explain why women are disproportionately affected.
I believe there’s an important conclusion to draw: this situation particularly puts the healthcare workforce at risk. Since there are traditionally more women in the healthcare and social care sectors, it’s not just about the nursing profession, which is predominantly female in most OECD countries. These roles are essential components of the health and social care workforce, and they are disproportionately represented. Women are also biologically more likely to be affected by inflammatory and autoimmune diseases, which increases the strain. So, connecting the dots, this places a particular pressure on the healthcare workforce, which, in turn, negatively affects women, and it’s something we need to pay attention to.
Beyond research priorities, what key lessons from the Covid-19 crisis should guide Europe’s policy responses to Long Covid?
Frederico Guanais: One interesting point is that for many decades, we thought about the separate groups of communicable diseases and non-communicable diseases. Usually, these are discussed separately by different professionals and in different forums. However, what COVID-19 has shown us is that there is a much closer connection between these two, as COVID-19 is a communicable disease that impacts non-communicable conditions, like Long Covid. We should not treat these as separate entities because today’s healthcare system and its implications are so complex that we need to consider how these pathways of care intertwine. Many other examples highlight this connection, such as the relationship between HPV and cancer, multiple sclerosis, or COVID and immune disorders.
Investing in long-term health and prevention is crucial, as it benefits both areas. Preparedness agendas, for instance, should account for chronic conditions as well as infectious threats. Additionally, establishing a more coordinated approach to developing case definitions, clinical guidelines, and reporting on the long-term impacts of diseases is essential, something we realised we did not do well during the COVID pandemic. This is a lesson learned; it took too long to raise awareness and start these conversations. There is even a risk that, over time, people might overlook the significance of lingering health issues, thinking the pandemic is over and ignoring ongoing health concerns. Therefore, it’s vital to develop protocols that enable us to respond swiftly when new pandemic threats emerge.
This isn’t just about detecting the immediate consequences but also about assessing delayed or unexpected conditions to better understand the burden of infectious agents. Of course, prevention is always preferable, but as we’ve emphasised for decades, the social and economic costs of pandemics can be devastating. This example underscores the importance of ongoing investment in prevention and preparedness, not just in controlling the diseases themselves but also in mitigating their broader impacts.
What should be the key policy priorities for improving care for people living with Long Covid?
Frederico Guanais: A very important lesson is that there needs to be better coordination of care pathways to ensure that patients and their doctors can easily access diagnosis, management, and specialist referral services for Long Covid. Healthcare systems are often fragmented, leading to a lack of coordination. For example, PaRIS data show that one in three Long Covid patients has had to repeat health information from their records. It is crucial that health systems are equipped with a robust information infrastructure so that data follows the patient across different services. This data can also help identify populations at higher risk of Long Covid.
I believe we’re lagging behind and still need to establish the foundations for better understanding how to diagnose and measure Long Covid. Once this is in place, we can proceed to develop integrated health and social services that meet the specific needs of those affected by this disease. It has made it even clearer that data should follow the patient throughout different parts of the health system. Specifically, for Long Covid, adopting a consensus case definition to detect and measure the condition would be beneficial, as current methods vary. More discussion is needed to reach a consensus on detection and measurement, along with clearer clinical and occupational guidelines to help patients manage their symptoms. As I mentioned at the start, there is considerable variation in how these cases are treated.
It is also relevant to mention that Covid-19 vaccination substantially reduces the risk of developing Long Covid, some estimates suggest by as much as 30%. This is fundamental, and health authorities should continue promoting vaccination among the general population. There is a tendency for people to overlook the importance of this. I hope we can provide even more detailed information on the variation in policies adopted by OECD countries. We have an OECD policy survey that aims to identify gaps and assess progress in surveillance, diagnosis, management, and service coordination for Long Covid.
Why is the STOA workshop on Long Covid relevant and timely? What themes will you cover?
Frederico Guanais: So, we are approximately five years from the outbreak of the pandemic. We have had sufficient time to measure, analyse, and report on the long-term consequences of COVID-19. Naturally, countries have begun to reorganise their responses to the Long Covid disease burden in a more integrated manner. I believe this is a gradual process that is unfolding. It’s highly relevant and timely because it’s important to emphasise that this remains a lingering problem. It’s something that persists.
We consider ourselves fortunate to receive support from the European Commission for this initiative to assist Long Covid patients and to develop insights and actions. Through our work, we hope to continue providing updated data on the Long Covid healthcare policy landscape across UN and OECD countries. Our goal is to complete this by the end of the year. Some of the themes we will address include providing updated economic estimates of the cost of Long Covid to healthcare systems and economies, as well as capturing the true costs of the pandemic. We should work together to overcome this invisibility problem and to develop the best policy solutions to address Long Covid, and I’m really confident that the STOA workshop will be an important part of that.