Seroprevalence of SARS-CoV-2 antibodies in people with an acute loss in their sense of smell and/or taste in a community-based population in London, UK: An observational cohort study

Abstract

Background: Loss of smell and taste are commonly reported symptoms associated with coronavirus disease 2019 (COVID-19); however, the seroprevalence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibodies in people with acute loss of smell and/or taste is unknown. The study aimed to determine the seroprevalence of SARS-CoV-2 antibodies in a community-based population with acute loss of smell and/or taste and to compare the frequency of COVID-19 associated symptoms in participants with and without SARS-CoV-2 antibodies. It also evaluated whether smell or taste loss are indicative of COVID-19 infection.

Methods and findings: Text messages, sent via primary care centers in London, United Kingdom, invited people with loss of smell and/or taste in the preceding month, to participate. Recruitment took place between 23 April 2020 and 14 May 2020. A total of 590 participants enrolled via a web-based platform and responded to questions about loss of smell and taste and other COVID-19-related symptoms. Mean age was 39.4 years (SD ± 12.0) and 69.1% (n = 392) of participants were female. A total of 567 (96.1%) had a telemedicine consultation during which their COVID-19-related symptoms were verified and a lateral flow immunoassay test that detected SARS-CoV-2 immunoglobulin G (IgG) and immunoglobulin M (IgM) antibodies was undertaken under medical supervision. A total of 77.6% of 567 participants with acute smell and/or taste loss had SARS-CoV-2 antibodies; of these, 39.8% (n = 175) had neither cough nor fever. New loss of smell was more prevalent in participants with SARS-CoV-2 antibodies, compared with those without antibodies (93.4% versus 78.7%, p < 0.001), whereas taste loss was equally prevalent (90.2% versus 89.0%, p = 0.738). Seropositivity for SARS-CoV-2 was 3 times more likely in participants with smell loss (OR 2.86; 95% CI 1.27-6.36; p < 0.001) compared with those with taste loss. The limitations of this study are the lack of a general population control group, the self-reported nature of the smell and taste changes, and the fact our methodology does not take into account the possibility that a population subset may not seroconvert to develop SARS-CoV-2 antibodies post-COVID-19.

Conclusions: Our findings suggest that recent loss of smell is a highly specific COVID-19 symptom and should be considered more generally in guiding case isolation, testing, and treatment of COVID-19.

Trials registration: ClinicalTrials.gov NCT04377815.

Conflict of interest statement

The authors have declared that no competing interests exist.

Figures

Fig 1. Participant flowchart illustrating participant flow through the recruitment process.

Participant flowchart illustrating the participant flow through the recruitment process, from text invitations, through eligibility screening, questionnaire completion and testing [18]. Figures presented as % with total number (n). Age presented as mean age in years with standard deviation.

Fig 2

Reported frequency of loss of smell (A) and loss of taste (B) in participants with and without SARS-CoV-2 antibodies. A. Out of 440 participants with SARS-CoV-2 antibodies, 93.4% (n = 411) reported a loss of smell (complete loss of smell in 69.8%, n = 307 and partial loss of smell in 23.6%, n = 104) and 6.6% (n = 29) reporting no change. Out of 127 participants without SARS-CoV-2 antibodies, 78.7% (n = 100) reported a loss of smell (complete in 39.4%, n = 50 and partial in 39.4%, n = 50), and 21.2% (n = 27) reported no loss of smell. B. A total of 90.2% (n = 397) of participants with SARS-CoV-2 antibodies reported loss of taste (complete in 47.5%, n = 209 and partial by 42.7%, n = 188). No loss of taste was reported in 10.8% (n = 43) reported no loss of taste. In participants without SARS-CoV-2 antibodies, loss of taste was reported by 89.0% (n = 113) (complete in 26.8%, n = 34 and partial in 62.2%, n = 79). No loss of taste was reported in 11.0% (n = 14). A significantly greater percentage of participants with SARS-CoV-2 antibodies reported a loss of their sense of smell (93.4% versus 78.7%, p < 0.001) and complete loss of smell (69.8% versus 50%, p < 0.001) compared with participants without antibodies. SARS-CoV-2, severe acute respiratory syndrome coronavirus 2.