inclusion criteria: 1. adult out-patient (≥18 years of age) 2. previously diagnosed with coronavirus disease 2019 (covid-19) by laboratory confirmation using reverse transcriptase polymerase chain reaction (rt-pcr) for the detection of severe acute respiratory virus coronavirus 2 (sars-cov-2) 3. complaints of persistent olfactory disturbances, subjectively 4. quantitatively documented to have olfactory dysfunction by 1. butanol threshold test (btt) 2. smell identification test (sit) 5. all subjects give written informed consent 6. subjects must be available to complete the study and comply with study procedures.

inclusion criteria: 1. adult out-patient (≥18 years of age) 2. previously diagnosed with coronavirus disease 2019 (covid-19) by laboratory confirmation using reverse transcriptase polymerase chain reaction (rt-pcr) for the detection of severe acute respiratory virus coronavirus 2 (sars-cov-2) 3. complaints of persistent olfactory disturbances, subjectively 4. quantitatively documented to have olfactory dysfunction by 1. butanol threshold test (btt) 2. smell identification test (sit) 5. all subjects give written informed consent 6. subjects must be available to complete the study and comply with study procedures.

inclusion criteria: adult out-patient (≥18 years of age) previously diagnosed with coronavirus disease 2019 (covid-19) by laboratory confirmation using reverse transcriptase polymerase chain reaction (rt-pcr) for the detection of severe acute respiratory virus coronavirus 2 (sars-cov-2) complaints of persistent olfactory disturbances, subjectively quantitatively documented to have olfactory dysfunction by butanol threshold test (btt) smell identification test (sit) all subjects give written informed consent subjects must be available to complete the study and comply with study procedures.

inclusion criteria: adult out-patient (≥18 years of age) previously diagnosed with coronavirus disease 2019 (covid-19) by laboratory confirmation using reverse transcriptase polymerase chain reaction (rt-pcr) for the detection of severe acute respiratory virus coronavirus 2 (sars-cov-2) complaints of persistent olfactory disturbances, subjectively quantitatively documented to have olfactory dysfunction by butanol threshold test (btt) smell identification test (sit) all subjects give written informed consent subjects must be available to complete the study and comply with study procedures.

inclusion criteria: 1. adult out-patient (≥18 years of age) 2. previously diagnosed with coronavirus disease 2019 (covid-19) by laboratory confirmation using reverse transcriptase polymerase chain reaction (rt-pcr) for the detection of severe acute respiratory virus coronavirus 2 (sars-cov-2) 3. complaints of persistent olfactory disturbances, subjectively 4. quantitatively documented to have olfactory dysfunction by 1. butanol threshold test (btt) 2. smell identification test (sit) 5. all subjects give written informed consent 6. subjects must be available to complete the study and comply with study procedures.

inclusion criteria: 1. adult out-patient (≥18 years of age) 2. previously diagnosed with coronavirus disease 2019 (covid-19) by laboratory confirmation using reverse transcriptase polymerase chain reaction (rt-pcr) for the detection of severe acute respiratory virus coronavirus 2 (sars-cov-2) 3. complaints of persistent olfactory disturbances, subjectively 4. quantitatively documented to have olfactory dysfunction by 1. butanol threshold test (btt) 2. smell identification test (sit) 5. all subjects give written informed consent 6. subjects must be available to complete the study and comply with study procedures.