Loss of sense of smells associated with sour taste is a possible diagnostic marker for COVID-19

Abstract

The popularity of electronic cigarettes (e-cigs) that utilize nicotine salts has rapidly increased since the introduction of JUUL pods in 2015. The immunotoxicology of nicotine salts in the respiratory tract is understudied. We hypothesized that nicotine salt counteranions induce airway inflammation and alter immune responses to inhaled allergens independent of nicotine. METHODS: The nicotine salt counteranions lactate, levulinate, salicylate or benzoate (5% solution) were administered to C57BL/6J mice by oropharyngeal aspiration daily for three days (acute exposure model) or three times weekly for three weeks (persistent exposure model). In some studies, mice were also exposed to house dust mite (HDM) allergen alone or in combination with benzoate three times weekly for three weeks. Airway inflammation was assessed by enumeration of inflammatory cells in bronchoalveolar lavage fluid and lung histology. RESULTS: Acute exposure to nicotine salt counteranions induced an influx of neutrophils into the airways. Persistent exposure to nicotine salt counteranions resulted in a mixed neutrophilic and lymphocytic airway inflammatory response. Neither acute nor persistent exposure to nicotine salt counteranions caused airway eosinophilia. In a HDM-mediated allergic airway inflammation model, co-exposure to benzoate and HDM increased the percentage of airway neutrophils but decreased the percentage of eosinophils compared to HDM alone. CONCLUSIONS: Both acute and persistent exposure to nicotine salt counteranions induces airway inflammation in mice independent of nicotine. Benzoate also induced neutrophilic inflammation in a HDMmediated allergic airway inflammation model, suggesting that exposure to e-cigs containing nicotine salts may promote a neutrophilic asthma phenotype.

Olfactory recovery following infection with COVID-19: A systematic review

“…10 studies were conducted in Asia: Turkey (n = 5) [ 18 , 27 , 38 , 41 , 50 ], Iran (n = 2) [ 22 , 55 ], India (n = 2) [ 33 , 52 ], Israel (n = 1) [ 32 ]. Four studies were conducted in North America: United States (n = 4), [ 21 , 42 , 48 , 51 ]. Two studies were conducted in Africa: Egypt (n = 2) [ 34 , 49 ], and two in South America: Brazil (n = 1) [ 53 ], Chile (n = 1) [ 15 , 53 ].…”

“…Two studies were conducted in Africa: Egypt (n = 2) [ 34 , 49 ], and two in South America: Brazil (n = 1) [ 53 ], Chile (n = 1) [ 15 , 53 ]. Of the 44 studies, twenty-five (56.8%) reported no funding requirements for the project [ 16 , 18 , 19 , 22 , 27 – 30 , 32 , 33 , 39 , 40 , 42 – 47 , 49 – 51 , 53 , 58 ]; six (13.6%) studies reported funding for the project (sources included academic institutions, government and not-for-profit organizations) [ 15 , 24 , 25 , 31 , 48 , 57 ], and thirteen (29.5%) did not report whether funding was provided [ 17 , 21 , 23 , 26 , 37 , 38 , 52 , 54 – 56 , 58 , 59 ].…”

“…COVID-19 was confirmed by RT-PCR test in all but six studies that either used RT-PCR or serology as a diagnostic tool of COVID-19 [ 25 , 48 , 51 , 54 , 58 , 60 ]. Although most of the patients recruited within studies were not hospitalized due to COVID-19 infection [ 17 , 21 – 26 , 28 , 30 – 32 , 35 , 36 , 41 – 43 , 45 , 47 – 49 , 51 , 54 , 56 , 60 ], some did include patients hospitalized either for monitoring purposes or quarantine [ 18 , 19 , 33 , 52 , 55 , 57 – 59 ]. Twelve studies included a mixture of hospitalized and non hospitalized patients [ 15 , 19 , 20 , 27 , 29 , 34 , 38 – 40 , 46 , 50 , 53 ].…”

“…Amongst the 44 included studies, as shown in the Tables 1 – 3 , we identified the following study designs: cohort (n = 12) [ 15 – 18 , 20 , 28 – 31 , 57 – 59 ], cross-sectional (n = 11) [ 21 , 32 – 36 , 38 – 42 ], case-controls (n = 5) [ 22 , 23 , 43 – 45 ], case series (n = 4) [ 24 , 46 – 48 ], and other miscellaneous study designs (n = 12) [ 49 – 52 , 54 – 56 ]. Nine of the 44 studies were retrospective and evaluated patients at only one time point [ 19 , 32 , 38 – 40 , 42 , 48 , 50 , 56 ].…”

“…In studies that prospectively evaluated olfactory dysfunction, the timing of such evaluations varied greatly. The initial evaluations of olfaction were measured from the onset of either olfactory or general symptoms [ 15 , 20 , 25 , 26 , 28 , 31 , 43 – 45 , 53 , 60 ], from the time of positive COVID-19 test [ 16 , 21 , 23 , 33 , 34 , 38 , 45 , 46 , 57 , 59 ], from time of infection [ 24 , 51 ], during active phases of symptomatology [ 47 ], from the time of the swab [ 35 , 36 ], at initial home/clinic visit [ 27 , 30 ], at the time of admission to hospital [ 29 , 52 ], during the recovery period [ 17 , 22 ], after recovery/discharge [ 49 ], or at other specified times [ 41 , 54 , 55 ]. The timing and number of follow-up evaluations also varied amongst studies.…”