Smell disorders associated with COVID-19 infection

Polyunsaturated Fatty Acids as Potential Treatments for COVID-19-Induced Anosmia

Some individuals with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) experience anosmia, or loss of smell. Although the prevalence of anosmia has decreased with the emergence of the Omicron variant, it remains a significant concern. This review examines the potential role of polyunsaturated fatty acids (PUFAs), particularly omega-3 PUFAs, in treating COVID-19-induced anosmia by focusing on the underlying mechanisms of the condition. Omega-3 PUFAs are known for their anti-inflammatory, neuroprotective, and neurotransmission-enhancing properties, which could potentially aid in olfactory recovery. However, study findings are inconsistent. For instance, a placebo-controlled randomized clinical trial found no significant effect of omega-3 PUFA supplementation on olfactory recovery in patients with COVID-19-induced anosmia. These mixed results highlight the limitations of existing research, including small sample sizes, lack of placebo controls, short follow-up periods, and combined treatments. Therefore, more rigorous, large-scale studies are urgently needed to definitively assess the therapeutic potential of omega-3 PUFAs for olfactory dysfunction. Further research is also crucial to explore the broader role of PUFAs in managing viral infections and promoting sensory recovery.

Impaired olfaction post-coronavirus disease 2019: a systematic review of smell recovery predictive factors

Background

The devastating coronavirus disease (COVID-19) pandemic seemed not yet to cease. Numerous studies regarding its typical sign and symptoms have been done, presenting one of the most promising predictors of the infection: olfactory dysfunction. Although not life-threatening, the symptom could decrease one’s quality of life, especially if persistent throughout their entire life. Among the countless literature regarding loss of smell, only limited studies denote predictors of smell recovery. This systematic review aimed to bridge the knowledge gap of olfactory impairment prevalence and recovery predictors in people with COVID-19.

Methods

This review was carried out through journal databases, including PubMed, Science Direct, Google Scholar, and medRxiv. Literature published from 2020 to 2022 that complied with the inclusion and exclusion criteria was retrieved, scanned for duplicates with Zotero, and reported using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocols 2020 (PRISMA) guidelines.

Results

Of the 2243 studies, seven were assessed with the Prediction model Risk Of Bias ASsessment Tool (PROBAST) to analyze the risk of bias, which five cohort studies deemed relevant. Olfactory dysfunction, olfactory recovery, and its predictive factors are noted. This review is registered in PROSPERO (Registration Number CRD42022318412).

Conclusions

No clinical markers predicted the recovery of olfactory dysfunction, but patients who are more likely to recover are associated with younger age, female sex, and having COVID-19-related symptoms such as nasal congestion and trigeminal sensation. Modifiable factors are still dubious in predicting the olfaction recovery.

Evidences and perspectives of the use of probiotics, prebiotics, synbiotics, and postbiotics as adjuvants for prevention and treatment of COVID-19: A bibliometric analysis and systematic review

BACKGROUND

Coronavirus disease-19 (COVID-19) is an infectious disease transmitted by the virus responsible for the severe acute respiratory syndrome 2 (SARS-CoV-2), which exhibit several clinical manifestations including gastrointestinal symptoms.

SCOPE AND APPROACH

This review aimed to provide insights and perspectives for the use of probiotics, prebiotics, synbiotics, and postbiotics as adjuvants for prevention/treatment and/or modulation of the microbiota in COVID-19 patients. Eighty-four studies published in the Scopus database from the onset of the pandemic until December 2021 were assessed and submitted to a bibliometric analysis adapted from VOSviewer software.

KEY FINDINGS AND CONCLUSIONS

Through bibliometric analysis, it might be suggested that the modulation of the gut/lung microbiome is promising as an adjuvant for the prevention/treatment of COVID-19 patients, due to immunomodulation properties related to probiotics and prebiotics. So far, few clinical studies involving the application of probiotics in COVID-19 patients have been completed, but reduction in the duration of the disease and the severity of symptoms as fatigue, olfactory dysfunction and breathlessness, nausea and vomiting and other gastrointestinal symptoms were some of the main findings. However, probiotics are not recommended to immunocompromised patients in corticosteroid therapy. The future perspectives point to the modulation of the intestinal microbiota by probiotics, prebiotics, synbiotics, and postbiotics represent a promising adjuvant approach for improving the health of patients with COVID-19.

Could smell and taste dysfunction in COVID-19 patients be a sign of the clinical course of the disease?

Background

It could be of great benefit to determine smell and taste dysfunction in COVID-19 patients and to investigate the relationship between these symptoms and clinical characteristics as the determination of points requiring attention during the clinical course of the disease.

Method

Evaluations of patients diagnosed with COVID-19 were made using a questionnaire method. Those with smell and taste dysfunction completed a visual analog scale (VAS) to determine severity. The patients were evaluated at the end of 1 and 2 months.

Results

Evaluation was made of a total of 105 patients with a mean age of 55.9±17.6 years. Smell and taste dysfunction was present in 56 (53.3%) patients with a mean age of 48.7±17.6 years and the 49 (46.7%) patients with no smell and taste dysfunction had a mean age of 64±13.6 years. It was determined that as age increased, the complaints of smell and taste dysfunction decreased. Full recovery was determined in 31 (55%) patients after 1 month, and in 16 (28%) patients, smell and taste dysfunction continued at the end of the second month. The symptoms of smell and taste dysfunction were determined to last longer in patients with no comorbidities, no symptoms of fever or shortness of breath, and those treated as outpatients (p=0.043, p=0.031, p=0.034, p=0.028, respectively). In the older age patient group, the VAS scores were observed to be higher and the time to recovery was shorter (p=0.007, p=0.018, respectively).

Conclusion

Smell and taste dysfunction in COVID-19 patients is seen more as age decreases and recovery takes longer. Smell and taste dysfunction is seen more in patients with symptoms of cough, nasal obstruction, and headache and lasts longer in patients without symptoms of fever and shortness of breath, with no comorbidities and in those treated as outpatients.