Time Lag between COVID-19 Diagnosis and Symptoms Onset for Different Population Groups: Evidence That Self-Testing in Schools Was Associated with Timely Diagnosis among Children.

Early identification of COVID-19 cases has been vital for reducing transmission and enabling treatment. In Greece, in autumn 2021 when Delta was the predominant circulating variant, unvaccinated citizens had to be tested before attending activities, and self-testing was required twice a week for students (5-17 years). Here, we describe the time of diagnosis by age group and possible exposure to assess testing strategies (September to November 2021). Information on the presence of symptoms at the time of diagnosis was available for 69,298 cases; 24,855 (36%) were asymptomatic or tested the same day as onset (early diagnosis), 21,310 (31%) reported testing one day after, and 23,133 (33%) did so two or more days after the onset of symptoms. The median lag was 2 days (1-14). Early diagnosis significantly differed among age groups (p-value < 0.001) and was higher among children. For every one-year increase of age, the odds of an early diagnosis were reduced by 1%. Cases exposed during training activities or in settings such as accommodation centers and hospitals were more frequently diagnosed early. The percentage of persons having a positive self-test before a rapid test/PCR diagnosis ranged from 7% in the age group of 60 years and above to 86% in the age group of 5-17 years. The provision of self-tests in schools and increased testing in closed settings led to an earlier diagnosis and probably to a decreased transmission of the virus in the period during which Delta was the predominant variant in Greece. However, more effort is needed for early diagnosis of adults in the community, especially after the onset of symptoms.

A COVID-19 outbreak among migrants in a hosting facility in Greece, April 2020.

In April 2020, a coronavirus disease 2019 outbreak was identified among migrants/refugees in Greece. Overall, 155 of 450 hosted migrants and two of 46 employees were infected (attack rates: 34.4% and 4.3%, respectively). The mean age of infected migrants was 24.9 years (3 days-68 years). In addition, 177 community contacts were tested negative. Cases were cohorted in separate rooms from people tested negative. Surfaces were cleaned and disinfected daily. The implementation of measures for the containment of the outbreak was challenging due to language barriers and lack of space for cohorting. At that time, there was no official recommendation to the general population regarding the use of masks or other personal protective equipment. Extensive testing of vulnerable populations and building trust in order to report symptoms and comply with the recommendations are essential.

Population-based study of influenza and invasive meningococcal disease among Greek children during the COVID-19 pandemic.

BACKGROUND: Aiming to the containment of the coronavirus disease 2019 (COVID-19) pandemic, governments worldwide have implemented a series of non-pharmaceutical interventions. Many of them and especially school closures have impacted the circulation of multiple airborne pathogens among children and adolescents. This study investigates the incidence of influenza and invasive meningococcal disease among children aged 0-14 years in Greece during the COVID-19 pandemic. METHODS: Data regarding the number of influenza-like illness cases, influenza-related paediatric intensive care unit (PICU) admissions and invasive meningococcal disease cases among children 0-14 years old were obtained from the National Public Health Organization. The incidence of the two diseases during the COVID-19 pandemic period (2020/2021) was compared with that of the six preceding seasons (2014-2019). RESULTS: A notable decrease was observed in both influenza and invasive meningococcal disease cases during the period 2020/2021 compared with the years 2014-2019. The mean annual rate of influenza-like illness cases and influenza-related PICU admissions in children 0-14 years old has reduced by 66.9% and 100%, respectively, while the mean annual invasive meningococcal disease rate has declined by 70%. Both weekly influenza-like illness and monthly invasive meningococcal disease rates were significantly decreased. CONCLUSIONS: The activity of influenza and invasive meningococcal disease in the children and adolescents of Greece has decreased during the COVID-19 pandemic period. Reduced transmission is likely related to the public health measures that were implemented to control the pandemic. The value of these measures may have relevance to the future management of influenza or invasive meningococcal disease epidemics.

Role of diabetes mellitus in the clinical course and outcome of SARS-CoV-2 infected patients.

PURPOSE: Our aim was to study patients with diabetes mellitus and SARS-CoV-2-infection diagnosed during the first pandemic wave in Greece. METHODS: Cases were retrieved from the national database of SARS-CoV-2 infections. RESULTS: We studied 2624 SARS-CoV-2 infected cases, including 157 with diabetes. Patients with diabetes more often had other comorbidities (68.8 vs. 24.1%; p-value < 0.001). Among patients with diabetes, 149 (94.9%) developed symptomatic disease (COVID-19) compared to 1817 patients (73.7%) without diabetes (p-value < 0.001). A total of 126 patients with diabetes and COVID-19 were hospitalized and 41 died (27.5% case-fatality rate compared to 7.5% among patients without diabetes; p-value < 0.001). Patients with diabetes more often were hospitalized, developed complications, were admitted to the intensive care unit (ICU), received invasive mechanical ventilation, and died compared to patients without diabetes (p-values < 0.001 to 0.002 for all comparisons). Multivariate logistic regression analyses revealed that diabetes, having other comorbidities, and older age were significantly associated with higher risk for hospitalization, ICU admission, invasive mechanical ventilation, and death, and that obesity was significantly associated with higher risk for hospitalization, ICU admission, and mechanical intubation, while female gender protected against these outcomes. CONCLUSION: COVID-19 is associated with increased rates of serious morbidity and adverse outcome in patients with diabetes and represents a severe illness for them.

Transmission dynamics of SARS-CoV-2 within families with children in Greece: A study of 23 clusters.

There is limited information on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection clustering within families with children. We aimed to study the transmission dynamics of SARS-CoV-2 within families with children in Greece. We studied 23 family clusters of coronavirus disease 2019 (COVID-19). Infection was diagnosed by reverse-transcriptase polymerase chain reaction in respiratory specimens. The level of viral load was categorized as high, moderate, or low based on the cycle threshold values. There were 109 household members (66 adults and 43 children). The median attack rate per cluster was 60% (range: 33.4%-100%). An adult member with COVID-19 was the first case in 21 (91.3%) clusters. Transmission of infection occurred from an adult to a child in 19 clusters and/or from an adult to another adult in 12 clusters. There was no evidence of child-to-adult or child-to-child transmission. In total 68 household members (62.4%) tested positive. Children were more likely to have an asymptomatic SARS-CoV-2 infection compared to adults (40% vs 10.5%; P = .021). In contrast, adults were more likely to develop a severe clinical course compared with children (8.8% vs 0%; P = .021). In addition, infected children were significantly more likely to have a low viral load while adults were more likely to have a moderate viral load (40.7% and 18.6% vs 13.8% and 51.7%, respectively; P = .016). In conclusion, while children become infected by SARS-CoV-2, they do not appear to transmit infection to others. Furthermore, children more frequently have an asymptomatic or mild course compared to adults. Further studies are needed to elucidate the role of viral load on these findings.

SARS-CoV-2 Infection in Healthcare Personnel With High-risk Occupational Exposure: Evaluation of 7-Day Exclusion From Work Policy.

BACKGROUND: As of late February 2020, Greece has been experiencing the coronavirus disease 2019 (COVID-19) epidemic. Healthcare personnel (HCP) were disproportionately affected, accounting for ~10% of notified cases. Exclusion from work for 7 days was recommended for HCP with high-risk occupational exposure. Our aim was to evaluate the 7-day exclusion from work policy for HCP with high-risk exposure. METHODS: HCP with a history of occupational exposure to COVID-19 were notified to the Hellenic National Public Health Organization, regardless of their exposure risk category. Exposed HCP were followed for 14 days after last exposure. RESULTS: We prospectively studied 3398 occupationally exposed HCP; nursing personnel accounted for most exposures (n = 1705; 50.2%). Of the 3398 exposed HCP, 1599 (47.1%) were classified as low-risk, 765 (22.5%) as moderate-risk, and 1031 (30.4%) as high-risk exposures. Sixty-six (1.9%) HCP developed COVID-19 at a mean of 3.65 (range: 0-17) days postexposure. Of the 66 HCP with COVID-19, 46, 7, and 13 had a history of high-, moderate- or low-risk exposure (4.5%, 0.9%, and 0.8% of all high-, moderate-, and low-risk exposures, respectively). Hospitalization and absenteeism were more prevalent among HCP with high-risk exposure. A logistic regression analysis showed that the following variables were significantly associated with an increased risk for the onset of COVID-19: male, administrative personnel, underlying disease, and high-risk exposure. CONCLUSIONS: HCP with high-risk occupational exposure to COVID-19 had increased probability of serious morbidity, healthcare seeking, hospitalization, and absenteeism. Our findings justify the 7-day exclusion from work policy for HCP with high-risk exposure.

Association Between Upper Respiratory Tract Viral Load, Comorbidities, Disease Severity, and Outcome of Patients With SARS-CoV-2 Infection.

BACKGROUND: There is limited information on the association between upper respiratory tract (URT) viral loads, host factors, and disease severity in SARS-CoV-2-infected patients. METHODS: We studied 1122 patients (mean age, 46 years) diagnosed by polymerase chain reaction (PCR). URT viral load, measured by PCR cycle threshold, was categorized as high, moderate, or low. RESULTS: There were 336 (29.9%) patients with comorbidities; 309 patients (27.5%) had high, 316 (28.2%) moderate, and 497 (44.3%) low viral load. In univariate analyses, compared to patients with moderate or low viral load, patients with high viral load were older, more often had comorbidities, developed Symptomatic disease (COVID-19), were intubated, and died. Patients with high viral load had longer stay in intensive care unit and longer intubation compared to patients with low viral load (P values < .05 for all comparisons). Patients with chronic cardiovascular disease, hypertension, chronic pulmonary disease, immunosuppression, obesity, and chronic neurological disease more often had high viral load (P value < .05 for all comparisons). In multivariate analysis high viral load was associated with COVID-19. Level of viral load was not associated with any other outcome. CONCLUSIONS: URT viral load could be used to identify patients at higher risk for morbidity or severe outcome.

In-flight transmission of COVID-19 on flights to Greece: An epidemiological analysis.

BACKGROUND: The emergence in China in late 2019 and subsequent progression of a pandemic of a respiratory disease named coronavirus disease 2019 (COVID-19) was highly facilitated by international travel. We present 5 cases of probable in-flight transmission in Greece. METHODS: We studied international passengers arriving to or departing from Greece from February 26 through March 9, 2020. Contact tracing extended up to 4 days before the onset of symptoms and focused on close contacts. Close contacts were defined as persons sitting within a distance of <2 m for >15 min, including passengers seated two seats around the index case and all crew members and persons who had close contact with the index case. RESULTS: We investigated 18 international flights with 2224 passengers and 110 crew members. Main countries of departure included Northern Italy, Israel and the United Kingdom. In accordance with the national surveillance investigation, in these flights there were 21 index cases and 891 contact traced cases. Six index cases were symptomatic during the flight. Of the 891 contact traced cases, 4 passengers and 1 crew member developed laboratory-confirmed infection (3 with COVID-19 and 2 with asymptomatic infection); they travelled on the same flight with two COVID-19 cases. CONCLUSIONS: Air travel has played a central role in the progression of the COVID-19 pandemic. However, there are scarce data about in-flight transmission. Our extensive investigation showed five cases of probable in-flight transmission. Efforts should be placed in order to ensure the prompt implementation of appropriate infection control measures on board.