Since the outbreak of the SARS-CoV-2 pandemic, olfactory disorders have been reported as a frequent symptom of COVID-19; however, its pathogenesis is still debated. The aim of this review is to summarize the current understanding of the pathogenesis of smell impairment in the course of COVID-19 and to highlight potential avenues for future research on this issue. Several theories have been proposed to explain the pathogenesis of COVID-19-related anosmia, including nasal obstruction and rhinorrhea, oedema of the olfactory cleft mucosa, olfactory epithelial damage either within the olfactory receptor cells or the supporting non-neural cells (either direct or immune-mediated), damage to the olfactory bulb, and impairment of the central olfactory pathways. Although the pathogenesis of COVID-19-related anosmia is still not fully elucidated, it appears to be mainly due to sensorineural damage, with infection of the olfactory epithelium support cells via the ACE1 receptor and disruption of the OE caused by immense inflammatory reaction, and possibly with direct olfactory sensory neurons infection mediated by the NRP-1 receptor. Involvement of the higher olfactory pathways and a conductive component of olfactory disorders, as well as genetic factors, may also be considered.

SARS-CoV-2 variants pose a significant threat to global public health. However, their influence on disease severity, especially among young adults who may exhibit different clinical characteristics, is debatable. In this retrospective study of 229 young adults hospitalized with COVID-19, we investigated the differences between Poland’s second and third waves of the pandemic. To identify potential predictors of severe COVID-19 in young adults, we analyzed patient characteristics and laboratory findings between survivors and non-survivors and we performed logistic regression to assess the risk of death, mechanical ventilation, and intensive care unit treatment. We found no increase in COVID-19 severity comparing the third and second waves of the pandemic, indicating that the alpha variant had no influence on disease severity. In addition, we found that factors, such as obesity, comorbidities, lung involvement, leukocytosis, neutrophilia, lymphopenia, higher IG count, the neutrophil-to-lymphocyte ratio, C-reactive protein, procalcitonin, interleukin-6, D-Dimer, lactate dehydrogenase, high-sensitive troponin I, creatine kinase-myocardial band, myoglobin, N-terminal-pro-B-type natriuretic peptide, creatinine, urea and gamma-glutamyl transferase, lower estimated glomerular filtration rate, albumin, calcium and vitamin D3, possibly a decrease in red blood cell counts, hemoglobin and hematocrit, and an increase in creatine kinase during hospitalization may be associated with poor outcomes of COVID-19.

The COVID-19 pandemic affected the physical and mental health of people around the world and left unprepared health care systems struggling to mount an adequate response. Understanding the impact of COVID-19 on pregnancy in terms of perinatal and fetal outcomes is essential to propose strategies for mminimising viral transmission. Overall, 91 pregnant women in labour, or with indication for induction of labour, with COVID-19 were admitted to hospital. On the day of admission, each pregnant woman underwent a nasopharyngeal swab to validate SARS-CoV-2 infection. Whenever delivery was by caesarean section, an amniotic fluid sample was collected after uterus incision. Neonates were tested twice: first by nasopharyngeal swab at birth and secondly either at 24 h after (when babies were isolated) or at discharge (when rooming-in). All samples underwent rRT-PCR testing for SARS-CoV-2. The SARS-CoV-2 RNA tests by nasopharyngeal swab of the pregnant women produced positive results in 47 patients. This cohort gave birth to 48 infants who were double tested by nasopharyngeal swab and included in the prospective observational study. Moreover, in this same cohort, 39 amniotic fluid samples were taken during caesarean section. All samples underwent rRT-PCR testing for SARS-CoV-2 and came back negative. The study results suggest a low risk of vertical transmission of COVID-19 and favourable perinatal outcomes due to adequate preventative strategies. This approach may prove to be more beneficial in the new SARS-CoV-2 variants era.