Long COVID has different clinical trajectories depending on severity of initial infection

 New research to be presented at this year’s European Congress of Clinical Microbiology & Infectious Diseases (ECCMID) in Lisbon, Portugal (23-26 April), suggests that the clinical trajectories and characteristics of long COVID may be different depending on the severity of the initial SARS-CoV-2 infection.

 

The large population-based study conducted during the first three waves of the pandemic, by Dr Pontus Hedberg from the Karolinska Institutet, Stockholm, Sweden and colleagues, also found a substantially higher rate of outpatient primary care use among individuals with long COVID-19, indicating persistence of the condition well beyond the initial infection.

 

The occurrence and risk factors of post COVID-19 condition, more commonly known as long COVID, and associated healthcare use before and after initial infection remain poorly understood.

 

To find out more, researchers conducted a retrospective population-based cohort study of 205,241 adult residents (aged 18 or older) of the Stockholm Region who had received a positive SARS-CoV-2 test between 1st March 2020 and 31st July 2021, and were alive 90 days after their test result, with and without a long COVID diagnosis. Individuals were determined to have long COVID if they received a diagnosis of post COVID-19 condition anytime between 90 and 360 days after their first positive test.

 

Modelling was used to analyse associations between age, sex, severity of infection, underlying medical conditions, previous healthcare usage, sociodemographic factors (eg, region of birth, education level and residential area type) and long COVID in non-hospitalised, hospitalised patients, and ICU-treated individuals.

 

In addition, individuals with long COVID-19 were propensity score matched to individuals without long COVID-19 by these factors as well as month of first positive test to assess healthcare use before and after the initial infection.

 

Among 205,241 adults with SARS-CoV-2 infection, almost a third (32%) of those treated for COVID-19 in ICU developed long COVID, as well as 6% of those hospitalised, and 1% of outpatients.

 

Fatigue was the most common registered symptom diagnosis among non-hospitalised patients (26%); while shortness of breath was the most frequently registered symptom diagnosis in both hospitalised patients (23%) and those treated in ICU (39%).

 

Analyses suggest that women were more than twice as likely to be diagnosed with long COVID compared to men among individuals with milder forms of initial infection, who did not require hospital care. A weaker association with female sex was also found among hospitalised but not ICU-treated individuals.

A history of mental illness or asthma was associated with twice the risk of being diagnosed with long COVID in people with initially mild COVID-19. This association was less pronounced among hospitalised individuals, and not seen among ICU-treated individuals.

The study also found a strong association between a history of outpatient primary care visits and long COVID-19 in those with initially mild COVID-19, but not in those who were treated in hospital or the ICU.

In addition, the researchers found the rate of outpatient care visits in people with long COVID-19 were substantially higher in the 10-12 months after the initial infection compared to before, indicating persistence well beyond the acute infection.

According to Dr Hedberg, “Many of the symptoms and risk factors reported in this study have been previously implicated in long COVID, but different study populations, assessment windows, and definitions of long COVID-19 prevents direct comparison between different studies. To the best of our knowledge, this is the first time the long COVID diagnosis issued by the WHO has been investigated across different severities of the initial SARS-CoV-2 infection.“

He continues, “Our findings reveal different associations between age, sex, comorbidities, symptoms, and healthcare use in people with more severe and milder forms of disease, which indicates different clinical trajectories and characteristics of long COVID. Future research should focus on better understanding the persistence of this debilitating condition across different groups of individuals.”

Despite the important findings, this is a retrospective observational study of a new diagnosis, and as such the observed associations do not necessarily indicate causation. In addition, the researchers acknowledge that they were unable to explore the impact of SARS-CoV-2 vaccination or the recent Omicron variant on long COVID, or to rule out the possibility that other unmeasured factors may have affected the results.

The study was funded by EuCARE, Region Stockholm, Swedish Research Council, Swedish Heart and Lung Foundation and Emil and Wera Cornell Foundation.

This press release is based on an oral presentation 3658 at the European Congress of Clinical Microbiology & Infectious Diseases (ECCMID). All accepted abstracts have been extensively peer reviewed by the congress selection committee. There is no full paper at this stage, but the authors are happy to answer your questions. The research has not yet been submitted to a medical journal for publication. The abstract within have been update since submission to ECCMID, so the updated version is below. This is an oral presentation so no poster is available.

For full abstract click here

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COI STATEMENT

The authors declare no conflict of interest

https://www.eurekalert.org/news-releases/950651

Long Covid fatigue eased by four-week occupational therapy program

 Promising findings from a pilot long Covid rehabilitation programme in Ireland are being presented at this year’s European Congress of Clinical Microbiology & Infectious Diseases (ECCMID) in Lisbon, Portugal (23-26 April).

Post-COVID-19 syndrome, also known as long Covid, is estimated to affect at least 10% of people in Ireland who have had Covid. People from all ages and backgrounds are affected, with extreme fatigue one of the main symptoms.

This fatigue is beyond ordinary tiredness and affects day-to-day activities, including personal care, leisure activities and employment. Even basic tasks such as getting dressed and climbing the stairs can be exhausting.

“Long Covid is a new phenomenon and the exact long-term implications are unknown,” says Louise Norris, senior occupational therapist St James’s Hospital, Dublin, Ireland, who led the research.

“We became concerned after seeing increasing numbers of patients who were having difficulty carrying out everyday activities because of fatigue. Fatigue was also affecting their return to work.

“One of the key roles, and skills, of occupational therapy is to help people get back to their everyday activities.  We’ve previously helped those with other conditions, such as multiple sclerosis and rheumatoid arthritis, learn techniques to manage their fatigue and felt we could use that experience to address the needs of those with long-term fatigue post Covid.”

To find out more, Louise Norris and colleagues at St James’s Hospital and Trinity College Dublin developed a pilot occupational therapy Fatigue Management Education programme (FaME-PC).

The pilot programme in St James’s Hospital involved 53 patients (73% female), with a median age of 51, who had self-reported fatigue that was affecting their ability to take part in everyday activities.

Post-Covid symptom duration between 12 weeks and 12 months was reported by 36 (68%) participants. 13 (25%) reported post-Covid symptom duration >12 months.

At the start of the study, 52 participants (98%) reported moderate to severe fatigue. 38 participants (72%) reported moderate to severe breathing difficulties and half had difficulty with concentration and memory, known as brain fog

These symptoms caused moderate to severe disruption to return to work in 39 participants (74%), engagement in leisure activity in 34 participants (64%) and completion of everyday activities, such as preparing meals, driving or going for a walk, in 31 participants (58%).

The participants took part in three 1.5-hour-long group-based interventions delivered online by an occupational therapist over a four-week period.

These focused on self-management techniques to address everyday fatigue and brain-fog.  Topics covered included energy planning, dealing with stress and sleep hygiene.

Emphasis was placed on showing the participants how to identify their body and brain’s limit – allowing them to take a break before they reached the point of exhaustion.

The aim was to equip the participants with techniques they could practise in their day-to-day lives as much as possible.

Questionnaires about fatigue and energy levels, quality of life and concerns about wellbeing were filled in by the participants before the study and two weeks after the end of the four-week programme.

Preliminary analysis of the results showed significant improvements in all three areas: fatigue, quality of life and wellbeing concerns.

Louise Norris says: “There is an urgent need to find new and better ways of managing post-Covid fatigue and its wide-ranging, and in some cases, devastating, effects on people’s lives.

“Initial results from our pilot programme are highly promising. They show equipping patients with a range of practical techniques can result in meaningful improvements in fatigue and quality of life.  Patients also have fewer concerns about their wellbeing.”

The pilot has been extended and data collection is ongoing.

https://www.eurekalert.org/news-releases/950650

Ireland’s first exercised-based recovery program for COVID-19 patients

 Fatigue, breathlessness and other symptoms that persist after COVID-19 can be improved by a six-week virtual exercise programme, an Irish study being presented at this year’s European Congress of Clinical Microbiology & Infectious Diseases (ECCMID) in Lisbon, Portugal (23-26 April) suggests.

“Recovery from COVID-19 is complex, with many patients still experiencing persistent symptoms including breathlessness, debilitating fatigue, joint pains, chest pain and much more, weeks, months and, for some people, even years following acute infection,” says Kate O’Brien, of St James’s Hospital, Dublin, Ireland, a physiotherapist and the lead researcher.

“These symptoms can be present regardless of how severe their initial infection with SARS-CoV-2 may have been and affect their quality of life, ability to exercise, to work and to resume their normal societal roles.

“Many patients express a wish to get back into exercise but don’t know where to start and are too apprehensive or anxious to try on their own, fearing they may worsen their symptoms.

“Existing exercise classes for patients with other conditions do not cater for their needs and so we designed a specific recovery programme for COVID-19 patients.”

The programme, the first in Ireland, consists of two 50-minute virtual exercise classes a week, for a minimum of six weeks. Patients carry out circuits consisting of squats, lunges, stretches and other aerobic and strength-based exercises.

The intensity of the sessions increases gradually over time, as the patients build up their exercise tolerance.

Holding the classes virtually increases accessibility by allowing patients to log in from their office or home, as well as making it easier for patients who don’t live locally to participate.

Sixty patients (42% male, median age 45 years) who were experiencing persistent symptoms at least six weeks after being diagnosed with COVID-19 were referred to the recovery programme. Symptoms included including breathlessness on exertion, reduced exercise tolerance and muscle weakness.

Preliminary data on the first 40 to complete the programme is presented here.

Assessments were carried out the start and end of the programme to measure physical fitness and breathlessness (as assessed by the 6-Minute Walk Test), fatigue (Chalder Fatigue Score) and health-related quality of life (Short-Form-36 scores).

The programme led to a significant increase in the distance the participants could walk in six minutes. 

They were able to walk 34% further, on average, than at the start of the study (512.9m vs 382.4m). Improvements were seen in 93.5% of patients (defined as being able to walk at least 30m further), the rest experienced no change.

The patients also experienced a clinically significant improvement in breathlessness and improvements in quality of life. Improvements were seen in areas including ability to carry out everyday activities such as climbing the stairs and carry groceries, having more energy and feeling in better overall health.

Fatigue levels improved significantly in more than 70% of patients. 23% of patients experienced no change in their fatigue levels and none were more fatigued than before.  (One patient has, however, since left the class, due to worsening fatigue.)

Ms O’Brien, who devised the SJH Post-COVID-19 Virtual Recovery Programme, says: “These preliminary findings suggest a physiotherapist-delivered virtual post-COVID-19 recovery programme can improve exercise capacity, breathlessness and quality of life without exacerbating fatigue.”

Feedback has been collected from patients.  Examples include “Thank you for helping me to fall in love with exercise again” and “The classes gave me the confidence I really needed to get back to normality”.1

The authors declare no conflicts of interest.

This press release is based on oral presentation L0397 at the European Congress of Clinical Microbiology & Infectious Diseases (ECCMID) Annual Meeting. The material has been peer reviewed by the congress selection committee. There is no full paper at this stage.

https://www.eurekalert.org/news-releases/950649

New tool to assess Long COVID symptoms

 A comprehensive tool that can assess the symptoms of Long COVID has been developed at the University of Birmingham for use in research and clinical care.

Developed with patients that have lived experience of Long COVID, the tool can capture symptoms and their impact on everyday life.

Currently more than 200 symptoms are associated with Long COVID which can affect people for months after the original coronavirus infection has gone. These can affect many organs in the body and include breathlessness, fatigue, or brain fog and are estimated to affect around 1.3 million people in the UK and more than 100 million people worldwide.

Healthcare providers and researchers need reliable ways of measuring these symptoms as they are experienced by patients to help them develop new treatments and provide the best possible care.

A team from the University of Birmingham’s Centre for Patient-Reported Outcomes Research  designed the Symptom Burden Questionnaire™ for Long COVID to address this challenge. Patients can use it to report symptoms and the data can be used to help identify treatments, and test whether these are safe and effective. The approach is published today (27 April 2022) in the BMJ.

“People living with Long COVID say they experience a huge range of symptoms but getting these recognised by healthcare practitioners and policy-makers has been a struggle,” said senior author, Dr Sarah Hughes. “We designed and tested this tool with our patient partners to ensure it is as comprehensive as possible, while also not being burdensome for patients to complete.”

Public partner Karen Matthews from LongCOVID SOS noted “I participated in a study quite early on in my condition and the questionnaire used didn’t capture the breadth of what I was feeling. Being able to shape something that could record that experience more effectively is worthwhile and I hope it gives researchers and people like me taking part in future studies some valuable evidence.”

The resulting questionnaire measures different symptoms of Long COVID and the impact of these symptoms on daily life.  It was developed with extensive patient input following regulatory guidance, meaning its scores may be used to support regulatory decisions around the approval of new therapies for Long COVID and by policymakers.

The study was carried out in partnership with patient data technology specialist, Aparito Ltd, and funded by the National Institute for Health Research and UK Research and Innovation. The team plans to carry out more development and testing to explore how the tool can be used in routine clinical practice, including translating it for use in other countries and minority ethnic communities.

Further details regarding the measure and access for use can be found at www.birmingham.ac.uk/sbq

 

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JOURNAL

BMJ

METHOD OF RESEARCH

Data/statistical analysis

SUBJECT OF RESEARCH

People

ARTICLE TITLE

Development and validation of the Symptom Burden Questionnaire for Long COVID: a Rasch analysis.

ARTICLE PUBLICATION DATE

26-Apr-2022

https://www.eurekalert.org/news-releases/950741

Assessing power of T-cell immune response to Omicron BA.1 and BA.2

 Scholars from HSE University and the RAS Institute of Bioorganic Chemistry have demonstrated the efficiency of T-cell immune response against the Omicron variant of SARS-CoV-2. In approximately 90% of vaccinated Europeans, T-cell immunity was as effective against Omicron as with other variants. The results of the study were published in PeerJ.

The Omicron variant of SARS-CoV-2 caused a new wave of the global pandemic. The new mutations help the virus spread more effectively and avoid antibodies, which is why those who have already had the disease or who have been vaccinated are getting infected more often. At the same time, recent data shows that the severity of the disease in vaccinated patients is significantly lower than in people who have not contacted the virus.

The researchers assume that this can be explained by several factors. First, the Omicron variant is slower at infecting the human cells; second, there is a hypothesis that a lighter course of the disease is related to effective action of T-cell immunity.

To confirm this assumption, a team of researchers from the HSE Faculty of Biology and Biotechnology and the RAS Institute of Bioorganic Chemistry (Stepan Nersisyan, Anton Zhiyanov, Alexey Galatenko, Maxim Shkurnikov, Maria Zakharova, Irina Ishina, Inna Kurbatskaia, Azad Mamedov, Alexander Gabibov, and Alexander Tonevitsky) studied the Omicron variant for mutations that help it avoid the T-cell immune response.

The development of T-cell response starts from the recognition of virus peptides (short fragments of proteins) with the molecules of the human major histocompatibility complex (HLA). The more peptides that are recognised, the faster and more efficient T-cell immunity is. Virus mutations can change such peptides, which is why they can stop being recognised by HLA molecules, and the T-cell response will be less effective.

T-CoV, a bioinformatics algorithm, demonstrated that the Omicron variant avoided none of the HLA molecule variants. But it detected several HLA molecule variants that started to become less effective at recognizing the Omicron’s S-protein. An outstanding discovery was the HLA-DRB1*03:01 variant of the molecule. The most important peptide of the virus managed to avoid it. Interestingly, both types of Omicron, BA.1 and BA.2 (also known as ‘Stealth’), evaded immune response recognition, though this was achieved by completely different mutations.

The bioinformatics calculations were verified experimentally in a laboratory. The researchers proved that there is no binding between Omicron peptides and HLA-DRB1*03:01 molecule, which was expressed in vitro.

The researchers emphasise that the initial peptide from the Wuhan basic variant, as well as Delta peptide, are recognised effectively by this molecule.

The authors emphasise that the detected HLA-DRB1*03:01 variant is present in a big share of the global population: for example, in 8.9% of Europeans.

‘The population diversity of HLA molecules, as well as the specificity of their work do not let the virus avoid the T-cell immune response. But the virus has managed to hide its S-protein from one of the HLA molecules. Importantly, most of COVID-19 vaccines (Sputnik V, Pfizer, Moderna, AstraZeneca and some others) carry specifically this virus protein. This means that people with the variant HLA-DRB1*03:01 (who make up 9% of Europe’s population, for example) vaccinated by S-protein may suffer from a more severe course of the disease caused by the Omicron variant,’ said Alexander Tonevitsky, Dean of the HSE Faculty of Biology and Biotechnology.

 

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JOURNAL

PeerJ

DOI

10.7717/peerj.13354 

ARTICLE TITLE

Alterations in SARS-CoV-2 Omicron and Delta peptides presentation by HLA molecules

ARTICLE PUBLICATION DATE

27-Apr-2022

https://www.eurekalert.org/news-releases/950717

Tackling the consequences of Long Covid

 As the pandemic progresses, the number of people living with Long Covid will grow. But it remains unclear how and why Long Covid develops, whether it can be prevented, and how it is best treated. To better understand Long Covid, it is essential to comprehend the needs and priorities of those affected. A team of scientists at UZH’s Epidemiology, Biostatistics and Prevention Institute (EBPI) has now joined forces with representatives of Long Covid Switzerland and the Long Covid Network Altea to amplify the voices of those living with Long Covid.

The Long COVID citizen science board: First-of-its-kind

“Collaborative projects that bring together different stakeholders allow us to grasp the impact of such a new disease and hopefully effectively tackle the challenges for people living with Long Covid,” says Milo Puhan, professor of epidemiology and public health at UZH. For this purpose, a citizen science project was developed and supported by the Participatory Science Academy of the University of Zurich and ETH with seed financing in 2021.

The research team recruited a first-of-its-kind Long Covid citizen science board, including 21 people affected by Long Covid and seven with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). Board members met online to discuss their needs and identify the most relevant research areas. They acted as citizen scientists in co-shaping the study’s direction, analysis and findings.

From patients’ needs to research priorities

The study found that people affected by Long Covid and their families need answers to a long list of 68 questions, which fall into four areas: Medical (e.g. risk factors, diagnosis, treatment), healthcare services, socio-economic (e.g. impact on work and finances), and disease burden. Through an online survey, the research team asked the citizen scientists and 241 other people affected by Long Covid to rate and prioritize the 68 identified questions.

“The scientists empowered us to define those research topics which have the largest impact on our health and lives – not surprisingly the results reflect our top concern, which is that we still lack effective therapies,” says Chantal Britt, founder and president of Long Covid Switzerland.

Treatment, rehabilitation, disease management, healthcare services, ensuring care is not interrupted, awareness of Long Covid among doctors and nurses, and how often Long Covid occurs in children were the research areas of most importance to Long Covid patients. “Our findings suggest that in addition to adequate treatment options, people affected by Long Covid are currently mostly lacking a clear diagnosis and access to adequate care that meets their multidimensional needs,” says Sarah Ziegler, epidemiologist at the EBPI.

Future research agendas

The research team hopes that this study will guide the funding of future Long Covid research. Resources are limited and it is important to prioritize the areas of most relevance to those affected by Long Covid. “Our methodology can be adapted to other settings and health conditions and may pave the way towards future co-created and person-centered research agendas,” says Milo Puhan.

Contacts

Dr. Sarah Ziegler

Epidemiology, Biostatistics and Prevention Institute (EBPI)

University of Zurich

Phone +41 44 634 46 49

E-mail: sarah.ziegler@uzh.ch

 

Prof. Dr. Milo Puhan

Epidemiology, Biostatistics and Prevention Institute (EBPI)

University of Zurich

Phone: +41 44 634 46 10

E-mail: miloalan.puhan@uzh.ch

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JOURNAL

The Patient Patient-Centered Outcomes Research

DOI

10.1007/s40271-022-00579-7 

METHOD OF RESEARCH

Observational study

SUBJECT OF RESEARCH

People

ARTICLE TITLE

Long COVID Citizen Scientists: Developing a Needs‑Based Research Agenda by Persons Affected by Long COVID

ARTICLE PUBLICATION DATE

28-Apr-2022

https://www.eurekalert.org/news-releases/951137

Vaccination campaign messages often prove ineffective

 Conventional vaccination campaign messages often miss their targets. A study in eight European countries shows that information on the benefits of vaccines can even reduce the willingness to get immunized. The researchers also looked into the factors that influenced the impact of messages, including low health literacy.

Not many Covid-19 vaccination campaigns in Europe lived up to the hopes of the public health authorities. However, the results of past studies in various countries have yielded a mixed picture as to which communication strategies can increase vaccine uptake and which factors undermine certain messages. A team of the Technical University of Munich (TUM), the University of Trento and the London School of Economics and Political Science explored these questions in Bulgaria, France, Germany, Italy, Poland, Spain, Sweden and the UK.

During the intensive phase of the vaccination campaigns, in June 2021 (in April in Germany), more than 10,000 unvaccinated adults were initially provided online with general information on the available vaccines. Then they received one of three messages combining text and images or were assigned to a control group. Message 1 highlighted the efficacy of the available vaccines in reducing the risk of serious illness and death through Covid-19. Message 2 stressed the advantages of having a vaccination certificate, especially for travel. Message 3 presented the prospect of leisure-time activities without restrictions, for example restaurant and cinema visits, access to fitness studios and attendance at concerts. The participants were then asked whether they intended to be vaccinated against Covid-19 if given the opportunity during the following week.

Three messages effective only in Germany

The study, published in Science Advances, shows that the tested messages would be effective in boosting vaccination quotas only in Germany and, to a lesser extent, in the UK. In Germany the vaccination willingness was significantly higher in the three groups than in the control group. In the UK, the readiness was higher only when the message stressed the benefits of a vaccination certificate. In all other countries the messages were ineffective – or even produced results opposite to those intended: people in Spain and Italy, when informed of the reduced risk of illness through vaccines, were less likely to seek vaccination than the corresponding control groups.

Decisive factor: health literacy

Using data mining methods, the research team was able to carry out detailed analysis of various associations between the message effectiveness and sociodemographic characteristics as well as the following factors: citizens’ trust in their government, their literacy with regard to healthcare issues and the share of the population who believe in certain conspiracy theories. The scientists used existing surveys to obtain data on these factors (which are not to be seen as monocausal) for the various countries.

For all messages, the likelihood of achieving the desired effect was reduced in a country when the health literacy of the population was low. “This result surprised us,” says Matteo M. Galizzi, a professor of behavioural science at the London School of Economics and Political Science. “We had thought that understandable and clearly visualized information on Covid-19 would lead to an improved understanding of the disease among people with little prior knowledge and thus to a greater vaccination willingness.” In contrast, the study confirmed conjectures that citizens’ trust in their own government would have a positive effect on vaccination intention.

Older people less receptive

Where there was relatively high prevalence of conspiracy theories, neither the message on health benefits nor that on the prospect of future leisure-time options produced significant successes. “The analysis shows that this strong disinformation can also explain the negative impact of health information in Spain and Italy,” says Giuseppe A. Veltri, a professor in computational social science at the University of Trento.

The researchers saw differences between socio-economic groups. For example, men with low levels of educational attainment were more often convinced by the two messages highlighting advantages in everyday life and leisure time than men with the same profile in the control group. Among these men there was also a very pronounced effect in countries with a high level of trust in the government and low prevalence of conspiracy theories. Older people tended to be less receptive on the whole to all of the messages.

“Clearer differentiation in campaigns”

“During the pandemic, people often looked at other countries to see what was working better or worse. Our study showed that such comparisons have limited usefulness,” says Prof. Tim Büthe, Chair of International Relations at TUM. “A more promising approach is to investigate the existing conditions in every country and then adapt the policy measures and communication strategies accordingly. Policy makers can use our findings to inform messaging for upcoming Covid-19 booster campaigns.”

Janina Steinert, a professor of global health at TUM, who headed the study, says: “Messages encouraging people to get vaccinated should target the various groups more closely, both in terms of content and how they are communicated, for example via certain social media channels or with gender-based or age group-specific advertising. Where the public lacks trust in the government, individuals seen as role models by certain socio-economic groups can be chosen as communicators.”

However, if a communication campaign has poor prospects of success due to several known barriers, the research team recommends shifting the focus to other measures. These might include concrete incentives or individually assigned vaccination appointments, which can only be actively objected to. “In the long term, all countries should develop their citizens’ health literacy to improve the effectiveness of future vaccination campaigns,” says Steinert.

More information:
The study published in Science Advances is part of the project “PERISCOPE – Pan-European Response to the ImpactS of COVID-19 and future Pandemics and Epidemics”, which has received 10 million euros in EU funding. 32 partner institutions from 15 European countries are investigating the social, political and economic impacts of the pandemic.

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JOURNAL

Science Advances

DOI

10.1126/sciadv.abm9825 

METHOD OF RESEARCH

Experimental study

SUBJECT OF RESEARCH

People

ARTICLE TITLE

COVID-19 Vaccine Hesitancy in Eight European Countries: Prevalence, Determinants and Heterogeneity

ARTICLE PUBLICATION DATE

27-Apr-2022

COI STATEMENT

The authors declare that they have no competing interests.

https://www.eurekalert.org/news-releases/951135