Smell Outcome and Seropositivity Titre in Post-COVID-19 Patients

The aims of the study were to perform an olfactory assessment on patients active and post-COVID-19 using the culturally adapted Malaysian version Sniffin' Sticks identification smell test (mSS-SIT), to evaluate the patient olfactory outcome using a Malay short version of the Questionnaire of Olfactory Disorders-Negative Statements (msQOD-NS), as well as to evaluate seropositive titre (IgG) response using automated serology method.

Score for mSS-SIT was performed during the hospitalization, when patients had tested positive for SARS-CoV-2 (during COVID-19), and repeated after they had tested negative (after COVID-19). Also, each patient completed msQOD-NS and serology SARS-CoV-2 antibodies blood test was evaluated.

During COVID-19, 2 of our patients were anosmia (6.5%), 22 (70.9%) were hyposmia, and 7 (22.6%) were normosmia. We repeated mSS-SIT on these same patients after COVID-19, and none of these subjects were hyposmia or anosmia, as they achieved a score >12. All our patients had scored 21 using msQOD-NS, meaning no impact on quality of life as they had regained their normal olfactory function. In this study also, we obtained no correlation between smell test and seropositivity titre COVID-19, and antibody levels gradually decreased over time till 6 months and remained stable up to 12 months.

From this study, we know full recovery of the sense of smell can be expected post-COVID-19 infection and COVID-19 antibody persists in the body up to 12 months of infection.