The Conundrum of Giglio Island: Unraveling the dynamics of an apparent resistance to COVID-19 - A descriptive study.

OBJECTIVES: Despite an extensive risk of exposure to COVID-19, the residents of Giglio Island, Italy, did not develop any symptom of SARS-CoV-2. The present study aims to characterize the nature of exposure and to describe the local population dynamics underlying its apparent resistance to COVID-19. METHODS: Descriptive study of an islander partially-segregated population cohort based on a seroprevalence screening conducted from Aprile 29 to May 3, 2020 and including SARS-CoV-2 seroprevalence and viral prevalence in samples of saliva assessed through RT-qPCR. Serologic testing was performed using a COVID-19 IgG/IgM rapid test while molecular analyses were carried out by Allplex 2019-nCoV Assay (Seegene). RESULTS: A total of 634 residents out of 748 (84.8%) present at the time, and 89 non-residents underwent serological testing. 364 males and 359 females with a median age of 58.5 years. The serological screening identified one positive, asymptomatic subject. The Nucleic Acid Amplification Tests (NAAT) did not yield any positive result. CONCLUSION: Despite extensive exposure to SARS-CoV-2, possibly only one new asymptomatic infection occurred in this population, as documented by IgM positivity not confirmed by RT-qPCR. This may be due to unknown protective factors or chance. On the basis of this baseline study, using its population as a reference model, further investigations will be conducted to test the advanced hypotheses, focusing on the evaluation of a possible cross-reactivity to SARS-CoV-2 from exposure to endemic viruses.

The era of pulmonary surfactant from Laplace to nowadays.

The first observations on neonatal respiratory distress syndrome (RDS) were published by some obstetricians in England, France and Germany in the second half of the 18th century. The concept that RDS might involve the absence of something stems from the observations of a Swiss physiologist, Kurt von Neergaard, who published an article in 1929 about a fundamental principle of respiratory mechanics: the surface tension in the alveoli. Further early descriptions of the existence, composition, and synthesis of the surfactant complex and its physiologic role in maintaining alveolar stability were dependent on the pioneering contributions of Radford, Macklin, Pattle, and Clements (among others). But the final link, describing surfactant deficiency as a cause of RDS, came from Avery and Mead in 1959, when they showed lung extracts from babies with hyaline membrane disease deficient in surfactant. Understanding surfactant composition, function and therapeutic usefulness has increased exponentially over the last 50 years and this paper reorganizes the steps of the research in this field until nowadays. Most of the discussion concerns the fundamental role of lung surfactant in RDS of premature infants, and the success of exogenous surfactant replacement in the clinical therapy of this disease.