The inflammatory/anti‐inflammatory balance has an important role in the clinical course of severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) (coronavirus disease [COVID‐19]) infection, which has affected over 200 million people since it first appeared in China in December 2019. This study aimed to determine the effectiveness of montelukast, which has known anti‐inflammatory and bronchodilatory effects, in these patients. The prospective randomized controlled study included 180 patients who were hospitalized in the infectious diseases department of our hospital between May and July 2021 and were diagnosed with the delta variant of SARS‐CoV‐2 by real‐time polymerase chain reaction of nasopharyngeal swabs. The patients were divided into three groups and received only standard treatment according to national guidelines (Group 1) or standard treatment plus 10 mg/day montelukast (Group 2) or 20 mg/day montelukast (Group 3). Laboratory parameters and pulmonary function tests (PFTs) at admission and on Day 5 of treatment were compared. Comparison of laboratory parameters on Day 5 showed that Groups 2 and 3 had significantly lower levels of lactate dehydrogenase, fibrinogen, D‐dimer, C‐reactive protein, and procalcitonin compared with Group 1 (p = 0.04, 0.002, 0.05, 0.03, and 0.04, respectively). In the comparison between Groups 2 and 3, only fibrinogen was significantly lower in Group 3 (p = 0.02). PFT results did not differ between the groups at admission, while on Day 5, only Group 3 showed significant improvements in forced expiratory volume in 1 s, forced vital capacity, and peak expiratory flow 25–75 compared with admission (p = 0.001 for all). Montelukast may be beneficial in COVID‐19 patients to maintain the inflammatory/anti‐inflammatory balance, prevent respiratory failure through its bronchodilator activity, and reduce mortality.

Coronavirus disease 2019 (COVID‐19) is one of the most pressing health problems of this century, but our knowledge of the disease is still limited. In this study, we aimed to examine serum‐soluble urokinase plasminogen activator receptor (suPAR) and kidney injury molecule 1 (KIM‐1) levels based on the clinical course of COVID‐19. Our study included 102 patients over the age of 18 who were diagnosed as having COVID‐19 between September 2020 and December 2020 and a control group of 50 health workers over the age of 18 whose severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) PCR results were negative. KIM‐1 was measured by ELISA and suPAR by suPARnostic™ assay. Analysis of previously identified variables of prognostic significance in COVID‐19 revealed high neutrophil to lymphocyte ratio, lactose dehydrogenase, prothrombin time, C‐reactive protein, PaO₂/FiO₂, D‐dimer, ferritin, and fibrinogen levels in patients with severe disease (p < 0.05 for all). KIM‐1 and suPAR levels were significantly higher in COVID‐19 patients compared to the control group (p = 0.001 for all). KIM‐1 level was higher in severe patients compared to moderate patients (p = 0.001), while suPAR level was lower (p = 0.001). KIM‐1, which is believed to play an important role in the endocytosis of SARS‐CoV‐2, was elevated in patients with severe COVID‐19 and may be a therapeutic target in the future. SuPAR may have a role in defense mechanism and fibrinolysis, and low levels in severe patients may be associated with poor prognosis in the early period.

The COVID‐19 pandemic, which has ravaged our world for more than a year, still shapes our agenda with a scale of intensity that fluctuates over time. In our study, we aimed to determine the correlation between serum migration inhibitory factor (MIF) level and disease severity in COVID‐19 with different prognoses. Between 15 October 2020 and 20 January 2021, 110 patients over the age of 18 who were diagnosed with COVID‐19 and 40 volunteer healthcare personnel were included in our study. MIF levels were measured by enzyme‐linked immunosorbent assay. In the comparison of serum MIF values in the patient and control group, it was observed that the MIF level was significantly higher in patients with both moderate and severe COVID‐19 levels compared to the control group (p = 0.001, 0.001). In the comparison of serum MIF values of moderate to severe COVID‐19 patients, it was observed that MIF level was higher in severe patients (p = 0.001). In the receiver operating characteristic curve analysis performed to differentiate between severe and moderate COVID‐19 patients with MIF levels, the area under the curve was observed as 0.78. When the cutoff value of the MIF level was taken as 4.455 ng/ml, the sensitivity was 83% and the specificity was 62%. Failure to adequately balance the pro‐inflammatory cytokines synthesized in COVID‐19 with anti‐inflammatory effect is the most important reason for the aggravation of the disease course. Playing a role in pro‐inflammatory cytokine synthesis, MIF can provide important information about the disease prognosis in the early period.

SARS-CoV-2 (COVID-19), which emerged in Wuhan, China in December 2019, infected more than six million people in a short time. In COVID-19, the relationship of many laboratory parameters to morbidity and mortality has been defined. In our study, we aimed to determine the relationship of serum vitamin D level to clinical course and prognosis. This study included 108 patients; 88 patients who stayed in Ataturk University and Erzurum City Hospital between March 24, 2020 and May 15, 2020, who were identified as COVID-19 by real-time PCR method from the nasopharyngeal swab and 20 asymptomatic voluntary medical personnel who tested negative for real-time PCR after routine check-up in our hospital. In statistical analysis conducted between healthy control group and vitamin D levels of patients admitted due to COVID-19, it was observed that patients infected with COVID-19 had a lower level (p= 0.004). In 20 patients developing MAS, a lower level of vitamin D was observed (p= 0.004) compared to 68 patients who did not develop. In the comparison of vitamin D levels of the patients (n= 8) who developed exitus in their follow up due to COVID-19, it was observed that vitamin D levels were statistically significantly lower compared to the living (p= 0.009). Due to COVID-19, pandemic, long-running quarantines caused insufficient use of sunlight and worsening of vitamin D deficiency. We wanted to draw attention again with our study to vitamin D which can be responsible for the heavy clinical course of COVID-19 and whose replacement is easy to apply.

In addition to the highly variable clinical presentation of acute COVID‐19 infection, it can also cause various postacute signs and symptoms. This study aimed to evaluate patients with postacute COVID‐19 over 12 weeks of follow‐up. The study included 151 patients who were diagnosed with COVID‐19 by real‐time polymerase chain reaction of a nasopharyngeal swab 1 month earlier, had radiologic findings consistent with COVID‐19 pneumonia, and presented to the post‐COVID‐19 outpatient clinic between May and August 2021. The patients were divided into three groups based on COVID‐19 severity: nonsevere pneumonia (Group 1), severe pneumonia (Group 2), and severe pneumonia requiring intensive care (Group 3). Evaluation of laboratory parameters at 4 and 12 weeks showed that Group 3 had a higher lactose dehydrogenase (LDH) level and a lower mean platelet volume than the other groups at both time points (p = 0.001 for all). Group 3 also had lower percent predicted forced vital capacity (FVC%), percent predicted forced expiration volume in 1 s (FEV1%), and percent predicted diffusion capacity of the lungs for carbon monoxide divided by alveolar volume (DLCO/VA%) compared to Groups 1 and 2 at Week 4 (p = 0.001, 0.004, 0.001, respectively) and compared to Group 1 at 12 weeks (p = 0.002, 0.03, 0.001, respectively). Patients with persistent dyspnea at 12 weeks had significantly lower FEV1%, FVC%, DLCO/VA%, and saturation levels in room air and significantly higher LDH, pro‐BNP, D‐dimer, and heart rate compared to those without dyspnea (p = 0.001 for all). Although the lungs are most commonly affected after COVID‐19 infection, vascular and endothelial damage also causes multisystem involvement. Our study indicates that laboratory values, radiological signs, and pulmonary functional capacity improved in most patients after 12 weeks of follow‐up.