Review of direct impact health indicators of COVID-19 in the scientific literature published between January 2020 and June 2021

Background

The Joint Action Population Health Information Research Infrastructure (PHIRI) seeks to create infrastructures to generate quality data on the COVID-19 pandemic between European countries. The aim of this study is to present a synthesis of health indicators used to evaluate the direct impact of COVID-19

Methods

Scoping review using a common search strategy in Pubmed, Embase and WHO Covid-19 databases. Health indicators of direct impact of COVID-19 were obtained from observational studies in the general population, hospitals and long-term care facilities from papers published worldwide in English between 01/01/2020 and 06/31/2021. Titles and abstracts were screened first by 15 reviewers using the Rayyan tool. Any discrepancies were solved by agreement between reviewers. Then, articles containing indicators of direct impact were selected in a full-text reading phase. Of them, a random sample of 35 was drawn and their indicators were described.

Results

After eliminating 262 duplicates 3891 records were reviewed. Screening discarded 3171 abstracts. Of 720 articles sought for retrieval, 445 met inclusion criteria for indicators extraction. In a sample of 35 papers (8.1%), 116 direct impact indicators of COVID-19 were identified. 28 morbidity indicators were found, classified as indicators of prevalence (n = 15), incidence (6), transmissibility (4) and underreported infection (4); 32 of mortality (mortality rate, 9; case fatality rate, 17; time to death, 2); and 54 for severity (complications, 27; mechanical ventilation, 12; hospitalization, 8; requiring ICU admission, 1; time from hospitalization to ICU admission, 1). Two composite indicators of severity and mortality were also identified.

Conclusions

According to the scientific literature, a wide variety of health indicators has been used to measure the direct impact of COVID-19. The systematization of indicators used in the current COVID-19 pandemic could help for future health crises management.

Moderate superoxide production is an early promoter of mitochondrial biogenesis in differentiating N2a neuroblastoma cells

Reactive oxygen species (ROS) have been widely considered as harmful for cell development and as promoters of cell aging by increasing oxidative stress. However, ROS have an important role in cell signaling and they have been demonstrated to be beneficial by triggering hormetic signals, which could protect the organism from later insults. In the present study, N2a murine neuroblastoma cells were used as a paradigm of cell-specific (neural) differentiation partly mediated by ROS. Differentiation was triggered by the established treatments of serum starvation, forskolin or dibutyryl cyclic AMP. A marked differentiation, expressed as the development of neurites, was detected by fixation and staining with coomassie brilliant blue after 48 h treatment. This was accompanied by an increase in mitochondrial mass detected by mitotracker green staining, an increased expression of the peroxisome proliferator-activated receptor gamma (PPARγ) coactivator 1-alpha (PGC-1α) and succinate dehydrogenase activity as detected by MTT. In line with these results, an increase in free radicals, specifically superoxide anion, was detected in differentiating cells by flow cytometry. Superoxide scavenging by MnTBAP and MAPK inhibition by PD98059 partially reversed differentiation and mitochondrial biogenesis. In this way, we demonstrated that mitochondrial biogenesis and differentiation are mediated by superoxide and MAPK cues. Our data suggest that differentiation and mitochondrial biogenesis in N2a cells are part of a hormetic response which is triggered by a modest increase of superoxide anion concentration within the mitochondria.

[Parachute tricuspid valve associated with Fallot's tetralogy]

Parachute deformity of the tricuspid valve was observed with a severe form of Fallot's Tetralogy with pulmonary atresia in a newborn. Signs of tricuspid stenosis (peripheral oedema, right atrial dilatation, hepatomegaly and conduction defects) were associated with the clinical signs of the principal malformation (severe hypoxaemia). To our knowledge, this is the first reported case of parachute deformity of the tricuspid valve.