Placebo's invisible brother: a restricted scoping review of the biomedical literature on the nocebo effect.

ABSTRACT: Placebos and their beneficial clinical and psychological effects are well-researched, but nocebo effects receive far less attention, despite being highly undesirable. The aim of this restricted scoping review was to examine how nocebo effects are represented in the biomedical literature and to identify the trends and gaps in existing knowledge. After searching 5 biomedical databases and 2 clinical trials registries (from their inception to December 23, 2020) for articles on nocebo effects or negative placebo effects, 1161 eligible publications were identified. The 2 main publication types were nonsystematic reviews (37.7%) and primary research studies (35.6%); only 85 publications (7.3%) were systematic reviews and meta-analyses. The nonsystematic reviews, many of them heavily opinion-based, may contribute to the amplification of narratives, attitudes, and beliefs about nocebo effects that do not objectively reflect the primary research. The primary research articles often used nocebo effects to explain results, rather than as the primary phenomenon under investigation. Most publications were concerned with both positive and negative placebo effects, rather than just nocebo effects. Over half of the abstracts were in the field of neurology, psychiatry, psychology, or neuroscience (52.8%). The nocebo effect was most frequently investigated in the context of pain. Studies were almost exclusively in adults and more often in healthy participants than in patients. In conclusion, in the biomedical literature, there is an overabundance of nonsystematic reviews and expert opinions and a lack of primary research and high-quality systematic reviews and meta-analyses specifically dealing with nocebo effects.

Infection and mortality of healthcare workers worldwide from COVID-19: a systematic review.

OBJECTIVES: To estimate COVID-19 infections and deaths in healthcare workers (HCWs) from a global perspective during the early phases of the pandemic. DESIGN: Systematic review. METHODS: Two parallel searches of academic bibliographic databases and grey literature were undertaken until 8 May 2020. Governments were also contacted for further information where possible. There were no restrictions on language, information sources used, publication status and types of sources of evidence. The AACODS checklist or the National Institutes of Health study quality assessment tools were used to appraise each source of evidence. OUTCOME MEASURES: Publication characteristics, country-specific data points, COVID-19-specific data, demographics of affected HCWs and public health measures employed. RESULTS: A total of 152 888 infections and 1413 deaths were reported. Infections were mainly in women (71.6%, n=14 058) and nurses (38.6%, n=10 706), but deaths were mainly in men (70.8%, n=550) and doctors (51.4%, n=525). Limited data suggested that general practitioners and mental health nurses were the highest risk specialities for deaths. There were 37.2 deaths reported per 100 infections for HCWs aged over 70 years. Europe had the highest absolute numbers of reported infections (119 628) and deaths (712), but the Eastern Mediterranean region had the highest number of reported deaths per 100 infections (5.7). CONCLUSIONS: COVID-19 infections and deaths among HCWs follow that of the general population around the world. The reasons for gender and specialty differences require further exploration, as do the low rates reported in Africa and India. Although physicians working in certain specialities may be considered high risk due to exposure to oronasal secretions, the risk to other specialities must not be underestimated. Elderly HCWs may require assigning to less risky settings such as telemedicine or administrative positions. Our pragmatic approach provides general trends, and highlights the need for universal guidelines for testing and reporting of infections in HCWs.