Background: The common cold is the most widespread viral infection in humans. Iota-carrageenan has previously shown antiviral effectiveness against cold viruses in clinical trials. This study investigated the efficacy of a carrageenan-containing nasal spray on the duration of the common cold and nasal fluid viral load in adult patients. Methods: In a randomized, double-blind, placebo-controlled trial, 211 patients suffering from early symptoms of the common cold were treated for seven days. Application was performed three times daily with either a carrageenan-supplemented nasal spray or saline solution as placebo with an overall observation period of 21 days. The primary endpoint was the duration of disease defined as the time until the last day with symptoms followed by all other days in the study period without symptoms. During the study, but prior unblinding, the definition of disease duration was adapted from the original protocol that defines disease duration as the time period of symptoms followed by 48 hours without symptoms. Results: In patients showing a laboratory-confirmed cold virus infection and adherence to the protocol, alleviation of symptoms was 2.1 days faster in the carrageenan group in comparison to placebo (p = 0.037). The primary endpoint that had been prespecified but was changed before unblinding was not met. Viral titers in nasal fluids showed a significantly greater decrease in carrageenan patients in the intention-to-treat population (p = 0.024) and in the per protocol population (p = 0.018) between days 1 and 3/4. Conclusions: In adults with common cold virus infections, direct local administration of carrageenan with nasal sprays reduced the duration of cold symptoms. A significant reduction of viral load in the nasal wash fluids of patients confirmed similar findings from earlier trials in children and adults. Trial registration: Current Controlled Trials ISRCTN80148028

Clinical trials applying iota-carrageenan nasal spray have previously shown to reduce duration of virus-confirmed common cold. The present study pooled data of two similar clinical trials to provide further evidence for the antiviral effectiveness of carrageenan. Individual patient data were analyzed from two randomized double blind placebo controlled trials assessing the therapeutic effectiveness of carrageenan nasal spray in acute common cold. Patients with virus-confirmed common cold (n = 254, verum 126, placebo 128) were included and the following parameters were appraised: duration of disease, number of patients with relapses, number of respiratory viruses and viral titers at inclusion (visit 1) compared to days 3–5 (visit 2). Carrageenan treated patients showed a significant reduction in duration of disease of almost 2 days (p < 0.05) as well as significantly fewer relapses during 21 days of observation period (p < 0.05). The virus clearance between visit 1 and visit 2 was significantly more pronounced in the carrageenan group (p < 0.05). In both studies, virus-confirmed common cold was caused by three main virus subtypes: human rhinovirus (46%), human coronavirus (25%) and influenza A (14%) virus. Carrageenan nasal spray showed significant antiviral efficacy in all three virus subgroups, the highest effectiveness was observed in human corona virus-infected patients. The reduced duration of disease was 3 days (p < 0.01) and the number of relapses was three times less (p < 0.01) in carrageenan treated corona-virus-infected patients compared to control patients. Administration of carrageenan nasal spray in children as well as in adults suffering from virus-confirmed common cold reduced duration of disease, increased viral clearance and reduced relapses of symptoms. Carrageenan nasal spray appeared as an effective treatment of common cold in children and adults. Pooled data from ISRCTN52519535 and ISRCTN80148028

Qualitative olfactory dysfunction is characterized as distorted odor perception and can have a profound effect on quality of life of affected individuals. Parosmia and phantosmia represent the two main subgroups of qualitative impairment and are currently diagnosed based on patient history only. We have developed a test method which measures qualitative olfactory function based on the odors of the Sniffin’ Sticks Identification subtest. The newly developed test is called Sniffin’ Sticks Parosmia Test (SSParoT). SSParoT uses hedonic estimates of two oppositely valenced odors (pleasant and unpleasant) to assess hedonic range (HR) and hedonic direction (HD), which represent qualitative olfactory perception. HR is defined as the perceivable hedonic distance between two oppositely valenced odors, while HD serves as an indicator for overall hedonic perception of odors. This multicenter study enrolled a total of 162 normosmic subjects in four consecutive experiments. Cluster analysis was used to group odors from the 16-item Sniffin’ Sticks Identification test and 24-additional odors into clusters with distinct hedonic properties. Eleven odor pairs were found to be suitable for estimation of HR and HD. Analysis showed agreement between test–retest sessions for all odor pairs. SSparoT might emerge as a valuable tool to assess qualitative olfactory function in health and disease.

Objectives: Olfactory dysfunction (OD) is a common symptom of Coronavirus Disease 2019 (COVID-19). Although many patients have been reported to regain olfactory function within the first month, long-term observation reports vary. Therefore, we aimed to assess the course of chemosensory function in patients diagnosed with COVID-19 within 3–15 months after the infection. Methods: One hundred and two patients (71 females and 31 males; mean age 38.8 years) diagnosed with laboratory-confirmed COVID-19 and subjective OD participated in this single-center study 111–457 days after onset of OD. Patients first performed chemosensory tests at home, followed by psychophysical testing (Sniffin’ Sticks (TDI), 27-item Candy Smell Test (CST), Taste Strips Test (TST)) in the clinic. Questionnaires regarding importance of olfaction (IOQ) and olfactory-specific quality of life (QOD) were applied at both timepoints. Results: After a mean 216 days (SD 73; range 111–457) between OD onset and follow-up testing, the mean Sniffin’ Sticks (TDI) score was 27.1 points (SD 5.8; range 4.25–38.5): 4.0% were anosmic, 72.5% hyposmic, and 23.5% normosmic. At follow-up testing, 73.5% of patients reported improvement, 5.9% deterioration, and 20.6% no change in OD. Moreover, full recovery of self-perceived smell, flavor, and taste was not observed. According to questionnaires, the individual importance of smell did not change, but participants showed improvement in OD-related quality of life (p < 0.001) and had increased parosmia scores (p = 0.014) at follow-up. Conclusion: Our results show that long-lasting OD after SARS-CoV-2 infection is a common symptom. The majority of patients had OD in the range of hyposmia, which was confirmed by comprehensive smell tests.

Chronic rhinosinusitis (CRS) is a common disease that substantially impairs the quality of life (QoL). Here, we aimed to assess patients’ QoL in different subtypes of CRS and correlated this with nasal polyp size to improve the clinical understanding of the burden of disease. In this retrospective single-center study, 107 patients with the following diagnoses were analyzed: CRS without nasal polyps (CRSsNP), CRS with nasal polyps (CRSwNP), or aspirin-exacerbated respiratory disease (AERD). Sino-Nasal Outcome Test-20 German Adapted Version (SNOT-20 GAV) scores and their correlation with endoscopic Total Polyp Scores (TPS) were evaluated. The mean SNOT-20 GAV scores were highest in patients with AERD (AERD = 43.4, CRSwNP = 36.3, CRSsNP = 30.9). A statistically significant correlation of total SNOT-20 GAV score with TPS was observed in CRSwNP patients (r = 0.3398, p = 0.0195), but not in AERD patients (r = 0.2341, p = 0.1407). When analyzing single SNOT-20 parameters, a strong correlation with TPS was observed for blockage/congestion of the nose, particularly in AERD patients (r = 0.65, p < 0.0001). The impact of nasal polyp size on the QoL differs amongst the subgroups of CRS. Nasal symptoms have the greatest impact on QoL in patients suffering from AERD. CRSwNP and AERD patients should be separately analyzed in clinical investigations and interpretations due to significant differences in QoL.

Odor (including flavor) perception plays a major role in dietary behavior. Orthonasal olfactory function (OOF) has been shown to decrease in obese subjects. Changes in retronasal olfactory function (ROF) after weight loss and in the individual significance of olfaction (ISO) in obesity are yet to be investigated. Firstly, 15 obese subjects were recruited in a pilot study and supported to conventionally lose weight. OOF (Sniffin’ Sticks) was measured at the beginning and after 5.6 ± 1.3 months. Eleven subjects re-visited but barely lost weight and no major changes in OOF were observed. Secondly, the body-mass-index (BMI), OOF, and ROF (Candy Smell Test, CST) were recorded in subjectively olfactory-healthy subjects (SOHSs) and additionally the ISO questionnaire was collected in patients with olfactory dysfunction (OD). BMI correlated significantly negatively with odor discrimination (p = 0.00004) in 74 SOHSs and negatively with CST (p < 0.0001) in 66 SOHSs. In 48 SOHSs, there was a gender difference in ISO scores (p = 0.034), but no significant correlation with BMI was found (p > 0.05). ISO scores were significantly higher in 52 OD patients in comparison to SOHSs (p = 0.0382). Not only OOF but also ROF may decline with higher BMI. ISO does not seem to alter with BMI, but olfaction becomes more important once it is consciously impaired.