Day by day symptoms following positive and negative PCR tests for SARS-CoV-2 in non-hospitalised health-care workers: a 90-day follow-up study (preprint)

Background Little is known about the long-term course of symptoms for mild coronavirus disease 2019 (COVID-19) when accounting for symptoms due to other causes. We aimed to compare symptoms day by day for non-hospitalised individuals who tested positive and negative with polymerase chain reaction for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Methods We followed 210 test-positive and 630 individually matched test-negative health-care workers of the Central Denmark Region up to 90 days after the test, April-June 2020. They daily reported seven COVID-19 related symptoms. Symptom courses were compared graphically and by conditional multivariable logistic regression. Results Thirty % of test-positive and close to zero of test-negative participants reported a reduced sense of taste and smell during all 90 days of follow-up (adjusted odds ratio [aOR] 86.07, 95% CI 22.86-323). Dyspnoea was reported by an initial 20% of test-positive with a gradual decline to about 5% after 30 days without ever reaching the level of the test-negative participants (aOR 6.88, 95% CI 2.41-19.63). Cough, headache, sore throat, muscle aches, and fever were temporarily more prevalent among the test positive participants, but after 30 days, no increases were seen. Women and participants aged 45 years or older tended to be more susceptible to SARS-CoV-2 infection. Conclusion Prevalence of long-lasting reduced sense of taste and smell is highly increased after being diagnosed with mild COVID-19. This pattern is also seen for dyspnoea at a low level but not for cough, sore throat, headache, muscle ache or pain, or fever. Key messages Reduced sense of taste and smell is present at a highly increased level of 30% during 90 days after testing positive for severe acute respiratory syndrome coronavirus 2 (SARS-Cov-2). Test-positive participants experience dyspnoea persistently more often than test-negative participants but affect only few. The prevalence of cough, sore throat, headache, muscle ache or pain, and fever following a positive test reach the level seen after a negative test within 30 days. Women and participants aged 45 years or older tend to be more susceptible to symptoms following SARS-CoV-2 infection.

SARS-CoV-2 seroprevalence survey among 18,000 healthcare and administrative personnel at hospitals, pre-hospital services, and specialist practitioners in the Central Denmark Region (preprint)

Objectives: The objective of this study was to perform a large seroprevalence survey on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) among Danish healthcare workers to identify high risk groups. Design: Cross-sectional survey. Setting: All healthcare workers and administrative personnel at the seven hospitals, pre-hospital services and specialist practitioner clinics in the Central Denmark Region were invited by e-mail to be tested for antibodies against SARS-CoV-2 by a commercial SARS-CoV-2 total antibody enzyme-linked immunosorbent assay (ELISA, Wantai Biological Pharmacy Enterprise Co., Ltd., Beijing, China). Participants: A total of 25,950 participants were invited. Of these, 17,987 (69%) showed up for blood sampling, and 17,971 had samples available for SARS-CoV-2 antibody testing. Main outcome measures: 1) Prevalence of SARS-CoV-2 antibodies; 2) Risk factors for seropositivity; 3) Association of SARS-CoV-2 RNA and antibodies. Results: After adjustment for assay sensitivity and specificity, the overall seroprevalence was 3.4% (CI: 2.5%-3.8%). The seroprevalence was higher in the western part of the region than in the eastern part (11.9% vs 1.2%, difference: 10.7 percentage points, CI: 9.5-12.2). In the high prevalence area, the emergency departments had the highest seroprevalence (29.7%) while departments without patients or with limited patient contact had the lowest seroprevalence (2.2%). Multivariable logistic regression analysis with age, sex, and profession as the predictors showed that nursing staff, medical doctors, and biomedical laboratory scientists had a higher risk than medical secretaries, who served as reference (OR = 7.3, CI: 3.5-14.9; OR = 4., CI: 1.8-8.9; and OR = 5.0, CI: 2.1-11.6, respectively). Among the total 668 seropositive participants, 433 (64.8%) had previously been tested for SARS-CoV-2 RNA, and 50.0% had a positive RT-PCR result. A total of 98% of individuals who had a previous positive viral RNA test were also found to be seropositive. Conclusions: We found large differences in the prevalence of SARS-CoV-2 antibodies in staff working in the healthcare sector within a small geographical area of Denmark and signs of in-hospital transmission. Half of all seropositive staff had been tested positive by PCR prior to this survey. This study raises awareness of precautions which should be taken to avoid in-hospital transmission. Additionally, regular testing of healthcare workers for SARS-CoV-2 should be considered to identify areas with increased transmission. Trial registration: The study is approved by the Danish Data Protection Agency (1-16-02-207-20).

Characteristics and predictors of hospitalization and death in the first 9,519 cases with a positive RT-PCR test for SARS-CoV-2 in Denmark: A nationwide cohort (preprint)

ObjectiveTo provide population-level knowledge on individuals at high risk of severe and fatal coronavirus disease 2019 (COVID-19) in order to inform targeted protection strategies in the general population and appropriate triage of hospital contacts. Design, Setting, and ParticipantsNationwide population-based cohort of all 228.677 consecutive Danish individuals tested (positive or negative) for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA from the identification of the first COVID-19 case on February 27th, 2020 until April 30th, 2020. Main Outcomes and MeasuresWe examined characteristics and predictors of inpatient hospitalization versus community-management, and death versus survival, adjusted for age-, sex- and number of comorbidities. ResultsWe identified 9,519 SARS-CoV-2 PCR-positive cases of whom 78% were community-managed, 22% were hospitalized (3.2% at an intensive care unit) and 5.5% had died within 30 days. Median age varied from 45 years (interquartile range (IQR) 31-57) among community-managed cases to 82 years (IQR 7589) among those who died. Age was a strong predictor of fatal disease (odds ratio (OR) 14 for 70-79-year old, OR 26 for 80-89-year old, and OR 82 for cases older than 90 years, when compared to 50-59-year old and adjusted for sex and number of comorbidities). Similarly, the number of comorbidities was strongly associated with fatal disease (OR 5.2, for cases with [≥]4 comorbidities versus no comorbidities), and 82% of fatal cases had at least 2 comorbidities. A wide range of major chronic diseases were associated with hospitalization with ORs ranging from 1.3-1.4 (e.g. stroke, ischemic heart disease) to 2.2-2.7 (e.g. heart failure, hospital-diagnosed kidney disease, chronic liver disease). Similarly, chronic diseases were associated with mortality with ORs ranging from 1.2-1.3 (e.g. ischemic heart disease, hypertension) to 2.4-2.7 (e.g. major psychiatric disorder, organ transplantation). In the absence of comorbidities, mortality was relatively low (5% or less) in persons aged up to 80 years. Conclusions and RelevanceIn this first nationwide population-based study, increasing age and number of comorbidities were strongly associated with hospitalization requirement and death in COVID-19. In the absence of comorbidities, the mortality was, however, lowest until the age of 80 years. These results may help in accurate identification, triage and protection of high-risk groups in general populations, i.e. when reopening societies.