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.

The COVID-19 pandemic has challenged health systems around the world. Maternal-foetal medicine, which has been particularly affected, must consider scientific data on the physiological processes occurring in the pregnant woman’s body to develop relevant standards of care. Our study retrospectively compared the clinical and laboratory characteristics of 52 COVID-19 pregnant patients with 53 controls. Most of the pregnant patients required medical attention during the third trimester and therefore we propose that vaccination is needed prior to the 30th week of pregnancy. We found no differences between the 2 groups in the course of illness classification system, days of hospital stay, need for oxygen supplementation, need for mechanical ventilation, and ICU admission. Moreover, clinical manifestations and imaging findings were comparable. Pregnant patients needed a greater oxygen flow rate and required high flow oxygen therapy more frequently. Considering pregnancy-related physiological adaptations, we found that COVID-19 infection in pregnant patients is associated with higher levels of inflammatory markers, apart from serum ferritin, than in non-pregnant women, and concluded that biomarkers of cardiac and muscle injury, as well as kidney function, may not be good predictors of COVID-19 clinical course in pregnant patients at the time of admission, but more research needs to be conducted on this topic.

The aim of this study was to compare the estimated blood loss and the frequency of obstetric hemorrhage among pregnant women with and without COVID-19 infection. The study was carried out in the Department of Obstetrics and Gynecology, at the Central Clinical Hospital of the Ministry of the Interior and Administration in Warsaw, Poland. From 15 May 2020 to 26 April 2021, a total of 224 parturients with COVID-19 infection were admitted for labor. The control group consisted of 300 randomly recruited pre-pandemic deliveries that took place between 15 May 2019 and 26 April 2020 at the Department. The primary outcome was the presence of postpartum hemorrhage, defined as an estimated blood loss of ≥500 mL within 24 h after birth or the need to transfuse 2 or more units of packed red blood cells (pRBCs). Secondary outcomes were the difference between hemoglobin and hematocrit levels at 24 h postpartum, the number of pRBCs units transfused, and the need for transperitoneal drainage. After applying the propensity-score-matching procedure for postpartum bleeding risk factors, 325 eligible patients were included in the final analysis, divided into 203 COVID-19 positive and 122 COVID-19 negative prepandemic deliveries. SARS-CoV-2 infected patients were characterized by a longer activated partial thromboplastin time (APTT), a reduced prothrombin time (PT), and lower platelet count at initial presentation. COVID-19 deliveries were found to be associated with a higher frequency of postpartum hemorrhage, an increased estimated blood loss, the more frequent use of peritoneal drainage, and more pRBCs units transfused. During the pandemic, an increased risk of postpartum hemorrhage posed another threat to SARS-CoV-2 infected pregnant women. It is essential to be aware of this when approaching COVID-19 delivery and to implement efficient preventative methods.

Coronavirus disease 2019 (COVID-19) was declared a pandemic and has spread around the globe, unsparingly affecting vulnerable populations. Effective prevention measures for pregnant women, who are particularly affected, include early identification of those patients at risk of developing in-hospital complications, and the continuous improvement of maternal-fetal treatment strategies to ensure the efficient use of health resources. The objective of our retrospective study was to determine which patient biomarkers on hospital admission correlate with disease severity as measured by disease course classification, the need for oxygen supplementation and higher demand for oxygen, the need for mechanical ventilation, intensive care unit admission, and length of hospital stay. Analysis of 52 PCR SARS-CoV-2 positive pregnant women revealed that the median date of hospital admission was the 30th gestational week, with dyspnoea, cough, and fever as the leading symptoms. The presence of diabetes and hypertension predisposed pregnant women to the severe course of illness. Lung involvement shown by CT scans on admission correlated with the greater clinical severity. The main laboratory predictors of disease progression were lymphocytopenia, hypocalcemia, low total cholesterol, low total protein levels, and high serum levels of C-reactive protein, ferritin, interleukin-6, glucose, lactate dehydrogenase, procalcitonin, and troponin I. Further research with a larger cohort of pregnant women is needed to determine the utility of these results for everyday practice.

Olfactory dysfunction (OD) is a common manifestation of COVID-19 and may be useful for screening. Survey-based olfactory evaluation tends to underestimate the prevalence of OD, while psychophysical olfactory testing during a pandemic has the disadvantage of being time consuming, expensive, and requiring standardized laboratory settings. We aimed to develop a quick, simple, affordable, and reliable test to objectively assess the prevalence and diagnostic accuracy of OD in COVID-19. The olfactory function of 64 COVID-19 inpatients and 34 controls was evaluated using a questionnaire and a simple disposable odor identification test (SDOIT) developed for this study. Four SDOIT models were assessed: 10-SDOIT, 9-SDOIT, 8-SDOIT, and 4-SDOIT, with 10, 9, 8 and 4 samples, respectively. We found a high frequency of self-reported OD in COVID-19 patients, with 32.8% and 42.2% reporting current and recent OD, respectively. Different SDOIT models revealed smell impairment in 54.7–64.1% of COVID-19 patients. The combination of either 10-SDOIT results and self-reported OD, or 8-SDOIT results and self-reported OD, were the best predictors of COVID-19, both with an AUC value of 0.87 (0.85 and 0.86 for the age-matched subjects). OD is a common symptom of COVID-19. A combination of self-reported smell deterioration and OD psychophysically evaluated using SDOIT appears to be a good predictor of COVID-19.