Household Exposure to Severe Acute Respiratory Syndrome Coronavirus 2 and Association With Coronavirus Disease 2019 Severity: A Danish Nationwide Cohort Study.

BACKGROUND: Households are high-risk settings for the transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Severity of coronavirus disease 2019 (COVID-19) is likely associated with the infectious dose of SARS-CoV-2 exposure. We therefore aimed to assess the association between SARS-CoV-2 exposure within households and COVID-19 severity. METHODS: We performed a Danish, nationwide, register-based, cohort study including laboratory-confirmed SARS-CoV-2-infected individuals from 22 February 2020 to 6 October 2020. Household exposure to SARS-CoV-2 was defined as having 1 individual test positive for SARS-CoV-2 within the household. Cox proportional hazards models were used to estimate the association between "critical COVID-19" within and between households with and without secondary cases. RESULTS: From 15 063 multiperson households, 19 773 SARS-CoV-2-positive individuals were included; 11 632 were categorized as index cases without any secondary household cases; 3431 as index cases with secondary cases, that is, 22.8% of multiperson households; and 4710 as secondary cases. Critical COVID-19 occurred in 2.9% of index cases living with no secondary cases, 4.9% of index cases with secondary cases, and 1.3% of secondary cases. The adjusted hazard ratio for critical COVID-19 among index cases vs secondary cases within the same household was 2.50 (95% confidence interval [CI], 1.88-3.34), 2.27 (95% CI, 1.77-2.93) for index cases in households with no secondary cases vs secondary cases, and 1.1 (95% CI, .93-1.30) for index cases with secondary cases vs index cases without secondary cases. CONCLUSIONS: We found no increased hazard ratio of critical COVID-19 among household members of infected SARS-CoV-2 index cases.

Symptom presentation of SARS-CoV-2-positive and negative patients: a nested case-control study among patients calling the emergency medical service and medical helpline.

OBJECTIVE: Currently effective symptom-based screening of patients suspected of COVID-19 is limited. We aimed to investigate age-related differences in symptom presentations of patients tested positive and negative for SARS-CoV-2. DESIGN: SETTING: Calls to the medical helpline (1-8-1-3) and emergency number (1-1-2) in Copenhagen, Denmark. At both medical services all calls are recorded. PARTICIPANTS: We included calls for patients who called for help/guidance at the medical helpline or emergency number prior to receiving a test for SARS-CoV-2 between April 1st and 20th 2020 (8423 patients). Among these calls, we randomly sampled recorded calls from 350 patients who later tested positive and 250 patients tested negative and registered symptoms described in the call. OUTCOME: RESULTS: After exclusions, 544 calls (312 SARS-CoV-2 positive and 232 negative) were included in the analysis. Fever and cough remained the two most common of COVID-19 symptoms across all age groups and approximately 42% of SARS-CoV-2 positive and 20% of negative presented with both fever and cough. Symptoms including nasal congestion, irritation/pain in throat, muscle/joint pain, loss of taste and smell, and headache were common symptoms of COVID-19 for patients younger than 60 years; whereas loss of appetite and feeling unwell were more commonly seen among patients over 60 years. Headache and loss of taste and smell were rare symptoms of COVID-19 among patients over 60 years. CONCLUSION: Our study identified age-related differences in symptom presentations of SARS-CoV-2-positive patients calling for help or medical advice. The specific symptoms of loss of smell or taste almost exclusively reported by patients younger than 60 years. Differences in symptom presentation across age groups must be considered when screening for COVID-19.

Consequences of coronavirus disease-2019 (COVID-19) lockdown on infection-related hospitalizations among the pediatric population in Denmark.

It remains unknown how Coronavirus disease-2019 (COVID-19) prevention measures implemented on March 12, 2020, have affected the rate of pediatric infection-related hospitalizations in Denmark. Therefore, we investigated the rate of pediatric infection-related hospitalizations during the COVID-19 pandemic. We used a retrospective cohort design and included all Danish children < 18 years. Infection-related hospitalizations were assessed during study periods in 2020 vs. 2018/2019, and we computed incidence rate ratios (IRRs) with 95% confidence intervals (CIs) using Poisson regression. In the 2020 study period, 3093 children were hospitalized with an infection, while the corresponding figures for 2018 and 2019 study periods were 4824 and 3830, respectively. When comparing the 2020 to the 2018/2019 study period prior to nationwide lockdown, we observed a decline in infection-related hospitalizations (12.68 (95% CI, 12.22-13.16) vs. 15.49 (95% CI, 15.12-15.86) per 1000 person-years). We further observed decreased IRRs, especially during the lockdown period (week 11: 0.64 (95% CI, 0.55-0.75); week 12: 0.26 (95% CI, 0.21-0.33); week 13: 0.13 (95% CI, 0.10-0.19)).Conclusion: The rate of pediatric infection-related hospitalizations in Denmark declined during the COVID-19 pandemic in 2020 compared to that in 2018/2019, with a 36% decline during initiation of the nationwide lockdown period. What is Known: • Due to the COVID-19 pandemic, several countries have implemented mitigation strategies such as lockdown of non-critical business functions. Most of these strategies have previously been proven effective on interruption of infection transmission. • It remains unclear how the mitigation strategies have affected the rate of pediatric infection-related hospitalizations. What is New: • Insight on how COVID-19 prevention measures have affected the frequency of infection-related hospitalization. • Valuable knowledge on how to act in potential future pandemics.

National all-cause mortality during the COVID-19 pandemic: a Danish registry-based study.

Denmark implemented early widespread social distancing to reduce pressure on the healthcare system from the coronavirus disease 2019 (COVID-19) pandemic, with the aims to reduce mortality. Unintended consequences might be delays in treatment for other diseases and subsequent mortality. We examined national all-cause mortality comparing weeks 1-27 in 2020 and 2015-2019. This registry-based study used Danish national registry data until 5 July 2020. We examined all-cause mortality rates among all deaths recorded from 2015 to 2020 and among chronic conditions (cardiovascular (cardiac & circulatory), chronic pulmonary, chronic kidney disease, cancer, and diabetes), comparing each week in 2020 to weeks in 2015-2019. In 2020, there were 28,363 deaths in weeks 1-27 (30 December 2019-5 July 2020), the mean deaths in 2015-2019 were 28,630 deaths (standard deviation 784). Compared to previous years, the mortality rate in weeks 3-10 of 2020 was low, peaking in week 14 (17.6 per 100,000 persons in week 9, 19.9 per 100,000 in week 14). Comorbidity prevalence among deceased individuals was similar in 2020 and 2015-2019: 71.1% of all deceased had a prior cardiovascular diagnosis, 30.0% of all deceased had a prior cardiac diagnosis. There were 493 deaths with COVID-19 in weeks 11-27, (59.8% male), and 75.1% had a prior cardiovascular diagnosis. Weekly mortality rates for pre-existing chronic conditions peaked in week 14, and then declined. During the COVID-19 pandemic, due to timely lockdown measures, the mortality rate in Denmark has not increased compared to the mortality rates in the same period during 2015-2019.