Challenges with medical tourism.

PURPOSE OF REVIEW: With the return of international travels to almost prepandemic levels, the number of patients who travel abroad to seek healthcare services is once again growing rapidly. Nevertheless, the expected benefits of medical tourism may be challenged by serious infectious complications. This review summarizes the evolving published evidence on infectious complications related with medical tourism of the last eighteen months. RECENT FINDINGS: There has been an increase of reported infectious complications in patients who had received healthcare abroad. Such complications were frequently associated with serious and prolonged morbidity, repeated treatments and hospitalizations, high healthcare costs, and occasionally fatalities. A devastating outbreak of fungal meningitis occurred among US residents who underwent epidural anesthesia for cosmetic surgery in two clinics in Mexico. Overall, as of July 5, 2023 there were 31 cases with severe cerebrovascular complications and eight deaths. Infections caused by nontuberculum mycobacteria and Candida sp have been also reported the last years. SUMMARY: Considering the expected expansion of medical tourism in the forthcoming years, public health authorities and scientific societies should raise awareness of such infections among physicians and other healthcare professionals and issue recommendations for their management. A system to report complications in patients receiving healthcare abroad is needed.

A study of the evolution of the third COVID-19 pandemic wave in the Athens metropolitan area, Greece, through two cross-sectional seroepidemiological surveys: March, June 2021.

We studied the third coronavirus disease 2019 (COVID-19) pandemic wave in Athens metropolitan area (3 738 901 inhabitants) through two seroepidemiological surveys. Persons presenting in 12 healthcare facilities across Athens in March and June 2021 were studied (764 and 901, respectively). Immunoglobulin G antibodies against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein were measured by a chemiluminescent microparticle immunoassay. In March the seroprevalence rate was 11.6%, meaning that 435 208 residents of Athens had evidence of immunity. The respective values in June were 55.7% and 2 082 568 residents. The highest seroprevalence rates attributed to SARS-CoV-2 infection were recorded in persons <18 years (16.3% in March and 31.6% in June), while immunity was mainly vaccine-induced in persons 18-64 years and >65 years. Infection-attributed immunity also increased in older-age groups. Wide ranges in seroprevalence rates were noted across areas in March and June. The highest seroprevalence rates were recorded in Piraeus (47.2%) and West Attica (37.5%). However, the highest increase (>5 times) occurred in Piraeus and the South Section of Athens, which are among the most densely populated areas in Athens. In both study periods, history of COVID-19 or febrile episode, and having a cohabitant with COVID-19 were associated with increased risk for seropositivity among unvaccinated persons (p values <0.001 for all). Residing in Piraeus, the South Section or West Attica was associated with increased risk for seropositivity in June (p values <0.001). Wide heterogeneity in seroprevalence rates was found across areas in Athens, which is mainly attributed to population density. The impact of population mobility and socioeconomic status should be explored.

Association Between Upper Respiratory Tract Viral Load, Comorbidities, Disease Severity, and Outcome of Patients With SARS-CoV-2 Infection.

BACKGROUND: There is limited information on the association between upper respiratory tract (URT) viral loads, host factors, and disease severity in SARS-CoV-2-infected patients. METHODS: We studied 1122 patients (mean age, 46 years) diagnosed by polymerase chain reaction (PCR). URT viral load, measured by PCR cycle threshold, was categorized as high, moderate, or low. RESULTS: There were 336 (29.9%) patients with comorbidities; 309 patients (27.5%) had high, 316 (28.2%) moderate, and 497 (44.3%) low viral load. In univariate analyses, compared to patients with moderate or low viral load, patients with high viral load were older, more often had comorbidities, developed Symptomatic disease (COVID-19), were intubated, and died. Patients with high viral load had longer stay in intensive care unit and longer intubation compared to patients with low viral load (P values < .05 for all comparisons). Patients with chronic cardiovascular disease, hypertension, chronic pulmonary disease, immunosuppression, obesity, and chronic neurological disease more often had high viral load (P value < .05 for all comparisons). In multivariate analysis high viral load was associated with COVID-19. Level of viral load was not associated with any other outcome. CONCLUSIONS: URT viral load could be used to identify patients at higher risk for morbidity or severe outcome.

Transmission dynamics of SARS-CoV-2 within families with children in Greece: A study of 23 clusters.

There is limited information on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection clustering within families with children. We aimed to study the transmission dynamics of SARS-CoV-2 within families with children in Greece. We studied 23 family clusters of coronavirus disease 2019 (COVID-19). Infection was diagnosed by reverse-transcriptase polymerase chain reaction in respiratory specimens. The level of viral load was categorized as high, moderate, or low based on the cycle threshold values. There were 109 household members (66 adults and 43 children). The median attack rate per cluster was 60% (range: 33.4%-100%). An adult member with COVID-19 was the first case in 21 (91.3%) clusters. Transmission of infection occurred from an adult to a child in 19 clusters and/or from an adult to another adult in 12 clusters. There was no evidence of child-to-adult or child-to-child transmission. In total 68 household members (62.4%) tested positive. Children were more likely to have an asymptomatic SARS-CoV-2 infection compared to adults (40% vs 10.5%; P = .021). In contrast, adults were more likely to develop a severe clinical course compared with children (8.8% vs 0%; P = .021). In addition, infected children were significantly more likely to have a low viral load while adults were more likely to have a moderate viral load (40.7% and 18.6% vs 13.8% and 51.7%, respectively; P = .016). In conclusion, while children become infected by SARS-CoV-2, they do not appear to transmit infection to others. Furthermore, children more frequently have an asymptomatic or mild course compared to adults. Further studies are needed to elucidate the role of viral load on these findings.

Coverage rates against vaccine-preventable diseases among healthcare workers in Sicily (Italy).

BACKGROUND: Vaccination of healthcare workers (HCWs) reduces the risk of occupational vaccine-preventable diseases (VPDs), prevents their nosocomial transmission and preserves healthcare delivery during outbreaks. Extensive implementation of vaccination programmes for HCWs allowed the elimination or control of several VPDs within healthcare facilities; despite these, the vaccine adherence rates among HCWs are persistently suboptimal. METHODS: A questionnaire was self-administered by HCWs to assess their vaccination rates against several VPDs and self-reported immunity in two university hospitals of Southern Italy (Catania and Palermo). RESULTS: A total of 2586 questionnaires were analysed. More than 50% of HCWs did not know their own immunization status against diphtheria, tetanus and pertussis. More than half of the HCWs interviewed at University Hospital (UH) of Catania (UHC) was immune against measles (72.1%), in contrast with data reported at the UH of Palermo (UHP) (45.9%). Immunization status against mumps (67.5% UHC vs. 40.6% UHP), rubella (69.9% UHC vs. 46.6% UHP) and varicella (70.4% UHC vs. 50.7% UHP). Overall, about 30% of HCWs did not know their own immunization status against these VPDs. Moreover, 84.2% at UHC and 66.7% at UHP stated that was previously vaccinated against hepatitis B. CONCLUSION: Vaccination coverage rates reported from the HCWs against influenza during the last three seasons were considerably low. In conclusion, totally inadequate vaccination rates against several VPDs were found in two university hospitals in Sicily, in terms of preventing not only disease transmission by susceptible HCWs, but also nosocomial outbreaks, confirming data from previous national and international studies.

Waterborne outbreak in a rural area in Greece during the COVID-19 pandemic: contribution of community pharmacies.

INTRODUCTION: On 15 June 2020, the National Public Health Organization was informed about the identification of two cases of Escherichia coli Ο157 infection in a small town in the Peloponnese Region in Greece and we suspected an outbreak. METHODS: We asked the local pharmacist to assist us to verify the outbreak by providing the daily number of over-the-counter anti-diarrheal drugs sold from 20 May 2020 onwards. The pharmacist asked customers with gastroenteritis to submit stool samples at the local hospital. Samples were tested for 22 pathogens. We conducted a 1 : 1 case-control study. Cases and controls were retrieved from the pharmacy client list. Chlorination records of the water supply system were retrieved, and water samples were tested for microbiological indicators and viruses. RESULTS: The increased number of sales of anti-diarrheal drugs verified the outbreak. Overall, 58 cases and 57 controls were recruited for the study. Tap water consumption (odds ratio (OR)=10.9, 95% confidence interval (CI)=3.1-38.0, p<0.001) and consumption of ice cubes made from tap water (OR=39.3, 95%CI=10.3-150.9, p<0.001) were independently associated with gastroenteritis occurrence. Eleven stool samples were tested; one was positive for shigatoxin-producing E. coli, one for enteropathogenic E. coli, four for E. coli Ο157 and one for Salmonella spp. Four samples tested negative. Five water samples collected on 18 June tested negative. The residual chlorine on 5 and 14 June ranged from 0.12 mg/L to 0.14 mg/L. CONCLUSION: This was the first investigation of a waterborne outbreak in Greece performed with the collaboration of a local pharmacy. The COVID-19 pandemic favored the use of alternative resources and channels of communication with the local population, which can also be used in the future, especially in remote areas of the country.

SARS-CoV-2 Infection in Healthcare Personnel With High-risk Occupational Exposure: Evaluation of 7-Day Exclusion From Work Policy.

BACKGROUND: As of late February 2020, Greece has been experiencing the coronavirus disease 2019 (COVID-19) epidemic. Healthcare personnel (HCP) were disproportionately affected, accounting for ~10% of notified cases. Exclusion from work for 7 days was recommended for HCP with high-risk occupational exposure. Our aim was to evaluate the 7-day exclusion from work policy for HCP with high-risk exposure. METHODS: HCP with a history of occupational exposure to COVID-19 were notified to the Hellenic National Public Health Organization, regardless of their exposure risk category. Exposed HCP were followed for 14 days after last exposure. RESULTS: We prospectively studied 3398 occupationally exposed HCP; nursing personnel accounted for most exposures (n = 1705; 50.2%). Of the 3398 exposed HCP, 1599 (47.1%) were classified as low-risk, 765 (22.5%) as moderate-risk, and 1031 (30.4%) as high-risk exposures. Sixty-six (1.9%) HCP developed COVID-19 at a mean of 3.65 (range: 0-17) days postexposure. Of the 66 HCP with COVID-19, 46, 7, and 13 had a history of high-, moderate- or low-risk exposure (4.5%, 0.9%, and 0.8% of all high-, moderate-, and low-risk exposures, respectively). Hospitalization and absenteeism were more prevalent among HCP with high-risk exposure. A logistic regression analysis showed that the following variables were significantly associated with an increased risk for the onset of COVID-19: male, administrative personnel, underlying disease, and high-risk exposure. CONCLUSIONS: HCP with high-risk occupational exposure to COVID-19 had increased probability of serious morbidity, healthcare seeking, hospitalization, and absenteeism. Our findings justify the 7-day exclusion from work policy for HCP with high-risk exposure.

Crimean-Congo haemorrhagic fever in a Greek worker returning from Bulgaria, June 2018.

We report a tick-borne case of severe Crimean-Congo haemorrhagic fever (CCHF) imported into Greece from Bulgaria. The patient presented severe thrombocytopenia, hemophagocytosis, haemodynamic instability, large haematomas and altered mental status. Supportive treatment and ribavirin were administered. Symptoms started one day after the tick was removed; the patient was discharged from the hospital 26 days after symptom onset. No secondary cases were observed. Phylogenetically the CCHF virus strain belongs to clade Europe 1.

Study of Greek children and youths with cystic fibrosis identifies immunisation gaps and delays.

AIM: Data about immunisation rates in cystic fibrosis (CF) patients are scarce. We estimated the rates and timeliness of immunisations in CF patients aged 0.55-22 years. METHODS: We studied 122 subjects at a hospital in Greece in 2014. A standard questionnaire was used to collect data and parents' opinions about immunisations. RESULTS: The complete immunisation rates were 92.6% for diphtheria-tetanus-acellular pertussis-inactivated poliomyelitis-Haemophilus influenzae (DTaP-IPV-Hib), 96.7% for hepatitis A, 97.4% for hepatitis B, 97.4% for measles-mumps-rubella, 85.1% for the varicella zoster virus, 85.1% for the meningococcus C conjugate, 84.3% for the pneumococcus conjugate and 58.9% for the bacillus Calmette-Guérin vaccine. Immunisation rates in youths were 64.4% for DTaP-IPV, 26.8% for the tetravalent meningococcus conjugate vaccine and 54.1% for the human papilloma virus vaccine. In addition, 30.1% received the 23-valent pneumococcal polysaccharide vaccine and 45.6% received annual influenza vaccines. Complete, up-to-date immunisation rates fell from 61.4% at 12 months of age to 14.5% at six and 12 years. All vaccines experienced delays. Most parents believed vaccines were necessary to protect their child's health. CONCLUSION: Our study of children with CF found immunisation gaps with no catch-up immunisations and these need to be administered at follow-up visits.

A 2009 cross-sectional survey of procedures for post-mortem management of highly infectious disease patients in 48 isolation facilities in 16 countries: data from EuroNHID.

PURPOSE: The handling of human remains may pose a risk for transmission of highly infectious agents. The use of appropriate biosafety measures is very important in case of management of patients deceased from highly infectious diseases (HIDs), such as Ebola virus disease. This paper presents the capabilities and resources in this field in 16 European countries, and suggests indications for the safe post-mortem management of HID patients. METHODS: The European Network for Highly Infectious Diseases conducted in 2009 a survey in 48 isolation facilities in 16 European countries. A set of standardized checklists, filled during on-site visits, have been used for data collection. RESULTS: Thirty-nine facilities (81.2%) reported to have written procedures for the management of human remains, and 27 (56.2%) for the performance of autopsies in HID patients. A Biosafety Level 3 autopsy room was available in eight (16.6%) facilities, other technical devices for safe autopsies were available in nine (18.7%). Overall, four facilities (8.3%) reported to have all features explored for the safe management of human remains. Conversely, in five (10.4%) none of these features were available. CONCLUSIONS: The level of preparedness of surveyed isolation facilities in the field of post-mortem management in case of HIDs was not satisfactory, and improvements are needed.

The role and utilisation of public health evaluations in Europe: a case study of national hand hygiene campaigns.

BACKGROUND: Evaluations are essential to judge the success of public health programmes. In Europe, the proportion of public health programmes that undergo evaluation remains unclear. The European Centre for Disease Prevention and Control sought to determine the frequency of evaluations amongst European national public health programmes by using national hand hygiene campaigns as an example of intervention. METHODS: A cohort of all national hand hygiene campaigns initiated between 2000 and 2012 was utilised for the analysis. The aim was to collect information about evaluations of hand hygiene campaigns and their frequency. The survey was sent to nominated contact points for healthcare-associated infection surveillance in European Union and European Economic Area Member States. RESULTS: Thirty-six hand hygiene campaigns in 20 countries were performed between 2000 and 2012. Of these, 50% had undergone an evaluation and 55% of those utilised the WHO hand hygiene intervention self-assessment tool. Evaluations utilised a variety of methodologies and indicators in assessing changes in hand hygiene behaviours pre and post intervention. Of the 50% of campaigns that were not evaluated, two thirds reported that both human and financial resource constraints posed significant barriers for the evaluation. CONCLUSION: The study identified an upward trend in the number of hand hygiene campaigns implemented in Europe. It is likely that the availability of the internationally-accepted evaluation methodology developed by the WHO contributed to the evaluation of more hand hygiene campaigns in Europe. Despite this rise, hand hygiene campaigns appear to be under-evaluated. The development of simple, programme-specific, standardised guidelines, evaluation indicators and other evidence-based public health materials could help promote evaluations across all areas of public health.

Preparedness of paediatric international travellers departing from Athens, Greece: an 18-month airport-based survey.

AIM: The number of children who travel to tropical and subtropical areas has increased. This study aimed to assess the preparedness of children departing from Greece to Africa and Asia, in terms of vaccination and malaria chemoprophylaxis. METHODS: An 18-month airport-based study was conducted in Athens between November 2011 and April 2013. RESULTS: Of the 183 children studied, 122 (66.7%) had a foreign nationality. Their main destinations were the Indian subcontinent (43.2%), South-East Asia (30.6%) and sub-Saharan Africa (14.2%). Just under three-quarters (73.2%) of the children were travelling to visit friends and relatives. Forty (21.9%) children had received pretravel services. Children visiting friends and relatives sought pretravel services less frequently than those who were not (17.9% versus 32.7%; p = 0.033). Female children and Greek nationals were significantly more likely to seeking pretravel services than males and foreign nationals (p = 0.007 and <0.001, respectively). The rabies and the typhoid fever vaccines were administered inadequately to children travelling to endemic areas, but malaria chemoprophylaxis was generally justified. CONCLUSION: Travel medicine services for children in Greece should be improved. There is a particular need to communicate with the parents of children visiting friends and relatives.

Asclepieia in ancient Greece: pilgrimage and healing destinations, the forerunner of medical tourism.

Asclepios, the first physician-demigod in Greek mythology, was born in Thessaly of the God Apollo and Coronis, a mortal mother. Asclepieia were healing sanctuaries dedicated to Asclepios. Asclepieia were located throughout the Eastern Mediterranean area, in ancient Greece and the Roman world. Travelers from all over the Mediterranean area seeking healing made pilgrimages to the Asclepieia, the early forerunner of "medical tourism".

National vaccination policies for health workers - A cross-sectional global overview.

BACKGROUND: Immunization is essential for safeguarding health workers from vaccine-preventable diseases (VPDs) that they may encounter at work; however, information about the prevalence and scope of national policies that protect health workers through vaccination is limited. Understanding the global landscape of health worker immunization programmes can help direct resources, assist decision-making and foster partnerships as nations consider strategies for increasing vaccination uptake among health workers. METHODS: A one-time supplementary survey was distributed to World Health Organization (WHO) Member States using the WHO/United Nations Children's Fund (UNICEF) Joint Reporting Form on Immunization (JRF). Respondents described their 2020 national vaccination policies for health workers - detailing VPD policies and characterising technical and funding support, monitoring and evaluation activities and provisions for vaccinating health workers in emergencies. RESULTS: A total of 53 % (103/194) Member States responded and described health worker policies: 51 had a national policy for vaccinating health workers; 10 reported plans to introduce a national policy within 5 years; 20 had subnational/institutional policies; 22 had no policy for vaccinating health workers. Most national policies were integrated with occupational health and safety policies (67 %) and included public and private providers (82 %). Hepatitis B, seasonal influenza and measles were most frequently included in policies. Countries both with and without national vaccination policies reported monitoring and reporting vaccine uptake (43 countries), promoting vaccination (53 countries) and assessing vaccine demand, uptake or reasons for undervaccination (25 countries) among health workers. Mechanisms for introducing a vaccine for health workers in an emergency existed in 62 countries. CONCLUSION: National policies for vaccinating health workers were complex and context specific with regional and income-level variations. Opportunities exist for developing and strengthening national health worker immunization programmes. Existing health worker immunization programmes might provide a foothold on which broader health worker vaccination policies can be built and strengthened.

Effectiveness of COVID-19 vaccination against school absenteeism in children and adolescents hospitalized with COVID-19.

BACKGROUND: COVID-19 vaccination has been recommended for children to protect them and to enable in-person educational and social activities. METHODS: We estimated COVID-19 vaccination effectiveness (VE) against school absenteeism in children 5-17 years old hospitalized from September 1, 2021 through May 31, 2023. Full vaccination was defined as two vaccine doses. RESULTS: We studied 231 children admitted to hospital with COVID-19, including 206 (89.2 %) unvaccinated/partially vaccinated and 25 (10.8 %) fully vaccinated. Unvaccinated/partially vaccinated children were absent from school for longer periods compared to fully vaccinated children (median absence: 14 versus 10 days; p-value = 0.05). Multivariable regression showed that full COVID-19 vaccination was associated with fewer days of absence compared to no/partial vaccination on average (adjusted relative risk: 0.77; 95 % CI: 0.61 to 0.98). COVID-19 VE was 50.7 % (95 % CI: -11.3 % to 78.2 %) for school absenteeism above the median duration of absenteeism. CONCLUSIONS: Full COVID-19 vaccination conferred protection against school absenteeism in hospitalized school-aged children with COVID-19.

Effectiveness of COVID-19 booster vaccination, morbidity and absenteeism among healthcare personnel during the 2022-2023 season dominated by Omicron BA.5 and BA.2 subvariants.

AIM: We assessed the vaccination effectiveness (VE) of a COVID-19 booster vaccine dose and the association between morbidity and absenteeism with COVID-19 booster vaccine receipt among healthcare personnel (HCP) in 2022-2023 in Greece. METHODS: We followed 5752 HCP from November 14, 2022 through May 28, 2023 for episodes of absenteeism. Absenteeism for non-infectious causes, pregnancy leave, or annual leave was not recorded. Full vaccination was defined as a primary vaccination series plus one booster dose within the past six months. Multivariable regression models were used to estimate the association of full COVID-19 vaccination with the outcomes of interest. RESULTS: A total of 1029 episodes of absenteeism occurred during the study period (17.9 episodes per 100 HCP). The mean duration of absence per episode was 5.2 days, and the total duration of absence was 5237 days. COVID-19 was diagnosed in 736 (12.8 %) HCP, asymptomatic SARS-CoV-2 infection in 62 (1.1 %) HCP, and influenza in 95 (1.7 %) HCP. Overall, COVID-19, influenza, and asymptomatic SARS-CoV-2 infection accounted for 71.5 %, 9.2 %, and 6.0 % of episodes of absenteeism, respectively. Multivariable regression models indicated that fully vaccinated HCP were absent from work for shorter periods [adjusted odds ratio (aOR): 0.42; 95 % confidence interval (CI): 0.21-0.83], were less likely to develop COVID-19 [aOR: 0.37; 95 % CI: 0.17-0.81)], and were more likely to develop an asymptomatic SARS-CoV-2 infection (aOR: 5.90; 95 % CI: 1.27-27.45). The adjusted full VE against COVID-19 was 62.8 % (95 % CI: 18.6 %-83.0 %). CONCLUSIONS: COVID-19 remains a significant cause of morbidity and absenteeism among HCP. Full COVID-19 vaccination status conferred significant protection against COVID-19 and was associated with shorter periods of absence from work.

Comparison of morbidity and absenteeism due to COVID-19 and seasonal influenza in a large cohort of health care personnel in the 2022 to 2023 season.

BACKGROUND: To compare the morbidity and work absenteeism associated with coronavirus disease 2019 (COVID-19) and influenza among health care personnel (HCP) in 2022 to 2023. METHODS: We followed 5,752 hospital-based HCP in Greece from November 14, 2022 through May 28, 2023. Symptomatic HCP was tested for SARS-CoV-2 and influenza by real-time polymerase chain reaction and/or rapid antigen detection test. The association between the duration of absenteeism and the type of disease was estimated by multivariable regression models. RESULTS: A total of 734 COVID-19 cases and 93 influenza cases were studied. The mean duration of absence per COVID-19 case was 5.8days compared with a mean of absence of 3.6days per influenza case (P value <.001). Overall, COVID-19 accounted for 4,245days missed during the study period compared with 333days missed due to influenza. Multivariable regression estimates indicated that HCP with COVID-19 had 1.91 more days of absenteeism (95% confidence interval 1.67-2.15) compared with those with influenza, on average. CONCLUSIONS: As SARS-CoV-2 becomes endemic, COVID-19 remains the prevalent cause of morbidity and absenteeism among HCP, accounting for considerably more workdays missed compared with influenza. HCP should be up-to-date with COVID-19 booster vaccinations and annual influenza vaccination in order to protect them as well as health care systems from HCP absenteeism.

The influenza landscape and vaccination coverage in older adults during the SARS-Cov-2 pandemic: data from Several European Countries and Israel.

INTRODUCTION: The Raise Awareness of Influenza Strategies in Europe (RAISE) group gathered information about the healthcare burden of influenza (hospitalizations, intensive care unit [ICU] admissions, and excess deaths), surveillance systems, and the vaccine coverage rate (VCR) in older adults in 18 European countries and Israel. AREAS COVERED: Published medical literature and official medical documentation on the influenza disease burden in the participating countries were reviewed from 2010/11 until the 2022/23 influenza seasons. Information on the framework for monitoring the disease burden and the provision for ensuring older adults had access to vaccination in their respective countries was provided. Data on influenza VCR in older adults were collected for the 2019/20 to 2022/23 influenza seasons. Data are reported descriptively. EXPERT OPINION: Influenza presents a significant healthcare burden in older adults. Reporting outcomes across participating countries is heterogeneous, highlighting the need for standardized approaches. Although older adults receive free influenza vaccination, vaccine uptake is highly variable among countries. Moreover, hospitalization rates remain high even in countries reporting a high VCR. Increased awareness and education on the burden of disease and the broader use of improved influenza vaccines for older adults may help reduce the disease burden on this population.

Panel stacking is a threat to consensus statement validity.

Consensus statements can be very influential in medicine and public health. Some of these statements use systematic evidence synthesis but others fail on this front. Many consensus statements use panels of experts to deduce perceived consensus through Delphi processes. We argue that stacking of panel members towards one particular position or narrative is a major threat, especially in absence of systematic evidence review. Stacking may involve financial conflicts of interest, but non-financial conflicts of strong advocacy can also cause major bias. Given their emerging importance, we describe here how such consensus statements may be misleading, by analysing in depth a recent high-impact Delphi consensus statement on COVID-19 recommendations as a case example. We demonstrate that many of the selected panel members and at least 35% of the core panel members had advocated towards COVID-19 elimination (zero-COVID) during the pandemic and were leading members of aggressive advocacy groups. These advocacy conflicts were not declared in the Delphi consensus publication, with rare exceptions. Therefore, we propose that consensus statements should always require rigorous evidence synthesis and maximal transparency on potential biases towards advocacy or lobbyist groups to be valid. While advocacy can have many important functions, its biased impact on consensus panels should be carefully avoided.