Effective control of rare diseases requires health programs based on principles of protection and prevention. Carrier screening programs serve as preventive measures by identifying at-risk groups. This review examines the impact, implementation, advantages, and disadvantages of carrier screening, incorporating examples from ten countries: the United States, Canada, the United Kingdom, Israel, China, Australia, Italy, Germany, the Netherlands, and Turkey. Data on carrier screening and related policies were collected from July to November 2022 and presented in a tabular format using a coding system devised by the authors. Variability was observed in the diseases/disorders and populations screened, screening expenses, and government provision across the countries. The number of diseases/disorders examined, ranging from 3 to 47, was determined by committee guidelines, government resources, pilot studies, and national institute resources. Notably, carrier screening programs exhibited greater worldwide inconsistency compared to newborn screening programs. The comparative analysis of developed countries serves to guide emerging nations. To address inequalities at both local and global levels, there is a need to enhance the establishment, development, and implementation of carrier screening programs. Furthermore, cost analyses of screening should be conducted, and adequate funding should be allocated to countries. In conclusion, this review highlights the preventive potential of carrier screening for rare diseases and emphasizes the importance of improving carrier screening programs globally to achieve equitable healthcare outcomes.

Nitrous oxide (N²O) was found responsible for genetic and reproductive toxicities, whereas it is widely used in paediatric care units where most healthcare providers are women of childbearing age. This motivated investigating occupational overexposure and overexposure factors in several paediatric hospital units. A cross-sectional study was carried out in seven healthcare units. On each of 34 healthcare providers, air samples were extracted (portable pumps and Tedlar^® bags) and N²O quantified (gas chromatography, pulsed discharge ionization detection, and infrared spectrometry). The data allowed calculating mean instantaneous exposures. The mean instantaneous exposure was: i) four times higher in closed vs. open treatment rooms; ii) two times higher in case of use vs. non-use of N²O; iii) significantly higher in junior vs. senior healthcare providers (by 12%); and, iv) higher during presumably short vs. presumably long procedures (by 20%). Overexposures to N²O were mainly seen in the emergency unit and in day hospitals for thoracic/abdominal diseases and nephrology. Overexposures were frequent during short-duration procedures; among 88 N²O measurements, 77 (87.5%) exceeded the 200 ppm threshold over 15 minutes. The overexposures call for dedicated treatment rooms (with adequate equipment and ventilation), more efficient anaesthetic practices, appropriate training, and regular checks.