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Epidemiology and Public Healthcare Systems during COVID-19

A special issue of International Journal of Environmental Research and Public Health (ISSN 1660-4601). This special issue belongs to the section "Global Health".

Deadline for manuscript submissions: closed (31 December 2022) | Viewed by 63286

Special Issue Editors


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Guest Editor
Itako Public Health Center of Ibaraki Prefectural Government, Itako 311-2422, Japan
Interests: COVID-19; public health; infectious disease; epidemiology

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Guest Editor
Public Health Center of Neyagawa City, Osaka 572-0838, Japan
Interests: epidemiology; cancer; COVID-19; infectious diseases; tobacco control

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Guest Editor
Department of Public Health, Faculty of Medicine and Graduate School of Public Health, International University of Health and Welfare, Ohtawara 324-8501, Japan
Interests: global health; COVID-19; occupational health; infectious diseases

Special Issue Information

Dear Colleagues,

Around two years have passed since coronavirus disease 2019 (COVID-19) emerged, having an unprecedented impact on humanity. Though considerable knowledge evolved during this period, many key questions are yet to be answered. While various new interventions have proven to be effective, we still suffer from novel challenges, such as variants of the virus which are of concern. Epidemiological implications and the responses of public health systems to COVID-19 vary at the national, regional, and local level. Several countries that were at first able to control the virus later experienced a strong resurgence again. Sharing and discussing individual experiences will add knowledge to current evidence and is significant for better understanding and surpassing challenges of the pandemic. In this special issue “Epidemiology and Public Health Systems during COVID-19” of the International Journal of Environmental Research and Public Health, we welcome you and your colleagues to submit manuscripts including articles, short communications, and reviews, addressing epidemiology and public health systems. Possible themes range, for example, from the epidemiological impact of COVID-19, contact tracing, and active surveillance to transmission dynamics, surge and decline, characteristics of SARS-CoV-2 variants, public health response and intervention, and implications on public health systems. We look forward to receiving your contributions on COVID-19 research.

Dr. Tsuyoshi Ogata
Prof. Dr. Hideo Tanaka
Prof. Dr. Koji Wada
Guest Editors

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Keywords

  • coronavirus disease 2019 (COVID-19)
  • epidemiology
  • transmission dynamics
  • SARS-CoV-2 variant
  • contact tracing
  • public health system intervention

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Published Papers (15 papers)

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Research

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19 pages, 3190 KiB  
Article
Impact of COVID-19 Preventative Measures on Otolaryngology in Taiwan: A Nationwide Study
by Hsiao-Yun Cho, Chia-Hung Hung, Yi-Wei Kao, Ben-Chang Shia and Mingchih Chen
Int. J. Environ. Res. Public Health 2023, 20(4), 3371; https://doi.org/10.3390/ijerph20043371 - 14 Feb 2023
Viewed by 1541
Abstract
Background: Taiwan always had low case rates of COVID-19 compared with other countries due to its immediate control and preventive measures. However, the effects of its policies that started on 2020 for otolaryngology patients were unknown; therefore, the aim of this study was [...] Read more.
Background: Taiwan always had low case rates of COVID-19 compared with other countries due to its immediate control and preventive measures. However, the effects of its policies that started on 2020 for otolaryngology patients were unknown; therefore, the aim of this study was to analyze the nationwide database to know the impact of COVID-19 preventative measures on the diseases and cases of otolaryngology in 2020. Method: A case-compared, retrospective, cohort database study using the nationwide database was collected from 2018 to 2020. All of the information from outpatients and unexpected inpatients with diagnoses, odds ratios, and correlation matrix was analyzed. Results: The number of outpatients decreased in 2020 compared to in 2018 and 2019. Thyroid disease and lacrimal system disorder increased in 2020 compared to 2019. There was no difference in carcinoma in situ, malignant neoplasm, cranial nerve disease, trauma, fracture, and burn/corrosion/frostbite within three years. There was a highly positive correlation between upper and lower airway infections. Conclusions: COVID-19 preventative measures can change the numbers of otolaryngology cases and the distributions of the disease. Efficient redistribution of medical resources should be developed to ensure a more equitable response for the future. Full article
(This article belongs to the Special Issue Epidemiology and Public Healthcare Systems during COVID-19)
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12 pages, 701 KiB  
Article
French General Practitioners’ Adaptations for Patients with Suspected COVID-19 in May 2020
by Aline Ramond-Roquin, Sylvain Gautier, Julien Le Breton, Yann Bourgueil and Tiphanie Bouchez
Int. J. Environ. Res. Public Health 2023, 20(3), 1896; https://doi.org/10.3390/ijerph20031896 - 19 Jan 2023
Cited by 2 | Viewed by 1809
Abstract
In France, towards the end of the first lockdown, COVID-19 management was largely transferred from hospitals to primary care. Primary care actors adapted their practices to ensure patients’ access to care, while limiting contamination. In this study, we aimed to identify patterns of [...] Read more.
In France, towards the end of the first lockdown, COVID-19 management was largely transferred from hospitals to primary care. Primary care actors adapted their practices to ensure patients’ access to care, while limiting contamination. In this study, we aimed to identify patterns of adaptations implemented by French general practitioners (GPs) in May 2020 for outpatients with confirmed or suspected COVID-19, and factors associated with these adaptions. A French survey concerning care organization adaptations, and individual, organizational, and territorial characteristics, was sent to GPs. Data were analyzed by multiple correspondence analysis followed by agglomerative hierarchical clustering to identify GPs’ adaptation clusters. A multinomial logistic regression model estimated the associations between clusters and individual, organizational, and territorial factors. Finally, 3068 surveys were analyzed (5.8% of French GPs). Four GPs’ adaptation clusters were identified: autonomous medical reorganization (64.2% of responders), interprofessional reorganization (15.9%), use of hospital (5.1%), and collaboration with COVID-19 outpatient centers (14.8%). Age, practice type and size, and territorial features were significantly associated with adaptation clusters. Our results suggest that healthcare systems should consider organizational features of primary care to effectively deal with future challenges, including healthcare crises, such as the COVID-19 pandemic, but also those linked to epidemiologic and societal changes. Full article
(This article belongs to the Special Issue Epidemiology and Public Healthcare Systems during COVID-19)
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12 pages, 802 KiB  
Article
SARS-CoV-2 Aerosol and Surface Detections in COVID-19 Testing Centers and Implications for Transmission Risk in Public Facing Workers
by Sarah J. Stein, Ashley R. Ravnholdt, Vicki L. Herrera, Danielle N. Rivera, Paul T. Williams and Joshua L. Santarpia
Int. J. Environ. Res. Public Health 2023, 20(2), 976; https://doi.org/10.3390/ijerph20020976 - 5 Jan 2023
Cited by 3 | Viewed by 1803
Abstract
The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and resulting COVID-19 (coronavirus disease 2019) pandemic have required mass diagnostic testing, often taking place in testing sites within hospitals, clinics, or at satellite locations. To establish the potential of SARS-CoV-2 aerosol transmission and to [...] Read more.
The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and resulting COVID-19 (coronavirus disease 2019) pandemic have required mass diagnostic testing, often taking place in testing sites within hospitals, clinics, or at satellite locations. To establish the potential of SARS-CoV-2 aerosol transmission and to identify junctures during testing that result in increased viral exposure, aerosol and surface samples were examined for the presence of SARS-CoV-2 RNA from locations within Nebraska Medicine COVID-19 testing and vaccine clinics. Aerosols containing SARS-CoV-2 RNA detected within clinics suggest viral shedding from infected individuals. SARS-CoV-2 RNA detection in aerosol samples was shown to correlate with clinic operation and patient infection, as well as with community infection findings. Additionally, SARS-CoV-2 RNA was detected in surface samples collected from clinics. The presence of SARS-CoV-2 RNA in aerosols in these clinics supports the continued use of respiratory protection and sanitization practices for healthcare workers, and other workers with public facing occupations. Full article
(This article belongs to the Special Issue Epidemiology and Public Healthcare Systems during COVID-19)
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12 pages, 943 KiB  
Article
Deferral of Non-Emergency Cardiovascular Interventions Triggers Increased Cardiac Emergency Admissions—Analysis of the COVID-19 Related Lockdown
by Dominik Felbel, Sascha d’Almeida, Manuel Rattka, Stefanie Andreß, Kathrin Reischmann, Benjamin Mayer, Armin Imhof, Dominik Buckert, Wolfgang Rottbauer, Sinisa Markovic and Tilman Stephan
Int. J. Environ. Res. Public Health 2022, 19(24), 16579; https://doi.org/10.3390/ijerph192416579 - 9 Dec 2022
Cited by 1 | Viewed by 1028
Abstract
Background: Data on the relation between non-emergency and emergency cardiac admission rates during the COVID-19 lockdown and post-lockdown period are sparse. Methods: Consecutive cardiac patients admitted to our tertiary heart center between 1 January and 30 June 2020 were included. The observation period [...] Read more.
Background: Data on the relation between non-emergency and emergency cardiac admission rates during the COVID-19 lockdown and post-lockdown period are sparse. Methods: Consecutive cardiac patients admitted to our tertiary heart center between 1 January and 30 June 2020 were included. The observation period of 6 months was analyzed in total and divided into three defined time periods: the pre-lockdown (1 January–19 March), lockdown (20 March–19 April), and post-lockdown (20 April–30 June) period. These were compared to the reference periods 2019 and 2022 using daily admission rates and incidence rate ratios (IRR). Results: Over the observation period from 1 January to 30 June, cardiac admissions (including non-emergency and emergency) were comparable between 2019, 2020, and 2022 (n = 2889, n = 2952, n = 2956; p = 0.845). However, when compared to the reference period 2019, non-emergency admissions decreased in 2020 (1364 vs. 1663; p = 0.02), while emergency admissions significantly increased (1588 vs. 1226; p < 0.001). Further analysis of the lockdown period revealed that non-emergency admissions dropped by 82% (IRR 0.18; 95%-CI 0.14–0.24; p < 0.001) and 42% fewer invasive cardiac interventions were performed (p < 0.001), whereas the post-lockdown period showed a 52% increase of emergency admissions (IRR 1.47; 95%-CI 1.31–1.65; p < 0.001) compared to 2019. Conclusions: We demonstrate a drastic surge of emergency cardiac admissions post-COVID-19 related lockdown suggesting that patients who did not keep their non-emergency appointment had to be admitted as an emergency later on. Full article
(This article belongs to the Special Issue Epidemiology and Public Healthcare Systems during COVID-19)
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7 pages, 309 KiB  
Article
SARS-CoV-2 Contamination of Ambulance Surfaces and Effectiveness of Routine Decontamination Procedure: A Classic Hygiene Lesson for A Novel Pathogen
by Tatjana Baldovin, Irene Amoruso, Matteo Paganini, Camilla Marcato, Riccardo Boscolo Cegion, Andrea Favaro, Chiara Bertoncello, Marco Fonzo and Vincenzo Baldo
Int. J. Environ. Res. Public Health 2022, 19(20), 13646; https://doi.org/10.3390/ijerph192013646 - 21 Oct 2022
Cited by 3 | Viewed by 1595
Abstract
The efficacy of standard operating procedures (SOPs) for the decontamination of ambulances against SARS-CoV-2 has been debated. In Italy, the differential use of ambulances was implemented by regional health authorities, with selected vehicles being used exclusively for transporting COVID-19 patients. We investigated the [...] Read more.
The efficacy of standard operating procedures (SOPs) for the decontamination of ambulances against SARS-CoV-2 has been debated. In Italy, the differential use of ambulances was implemented by regional health authorities, with selected vehicles being used exclusively for transporting COVID-19 patients. We investigated the presence of SARS-CoV-2 on high-touch surfaces in ambulances to assess contamination dynamics and the effectiveness of decontamination SOPs. Four high-touch surfaces were sampled before and after decontamination (T0; T1). The gloves of the EMS crew chief were also sampled. RNA extraction was performed with a commercial kit, followed by RT-qPCR molecular detection of SARS-CoV-2. A total of 11 transports were considered. Seven transports had at least one positive sample; all were related to a COVID-19 patient. Three of the negative transports had dealt with COVID-19 case, and one had dealt with a COVID-19-negative patient. One door handle and one oxygen knob were positive at T0, with negative T1 swabs. The monitors were positive in 5 transports at T0, yet they were never positive at T1. Three stretcher handles tested positive at T0, and two of them also at T1, possibly having bypassed decontamination during personnel dismounting. Gloves were contaminated in five transports, in which 1 to 3 additional samples (monitor, knob, stretcher) resulted as positive. Overall, the efficacy of decontamination SOPs was confirmed under the unprecedented conditions of the COVID-19 emergency. However, the importance of correct hand-hygiene and glove-disposal should be further emphasized through the dedicated training of EMS personnel. Full article
(This article belongs to the Special Issue Epidemiology and Public Healthcare Systems during COVID-19)
8 pages, 1334 KiB  
Article
Social Isolation, Hospitalization, and Deaths from Cardiovascular Diseases during the COVID-19 Epidemic in São Paulo Metropolitan Area in 2020
by Lucas Rodrigues de Lima, Paulo Francisco Auricchio da Ponte, Lucca Novais Dias, Marcelo Henrique Lima Silvestre, Paulo Jeng Chian Suen and Antonio de Padua Mansur
Int. J. Environ. Res. Public Health 2022, 19(17), 11002; https://doi.org/10.3390/ijerph191711002 - 2 Sep 2022
Cited by 1 | Viewed by 1428
Abstract
Background: The COVID-19 epidemic overloaded the São Paulo metropolitan area (SPMA) health system in 2020. The leading hospitals directed their attention to patients with COVID-19. At the same time, the SPMA Health Secretary decreed social isolation (SI), which compromised the care for cardiovascular [...] Read more.
Background: The COVID-19 epidemic overloaded the São Paulo metropolitan area (SPMA) health system in 2020. The leading hospitals directed their attention to patients with COVID-19. At the same time, the SPMA Health Secretary decreed social isolation (SI), which compromised the care for cardiovascular diseases (CVD), even though higher cardiovascular events were expected. Methods: This study analyzed mortality from CVD, ischemic heart disease (IHD), and stroke, along with hospital admissions for CVD, IHD, stroke, and SI in the SPMA in 2020. Data regarding hospitalization and mortality from CVD were obtained from the SPMA Health Department, and data regarding SI was obtained from the São Paulo Intelligent Monitoring System. Time-series trends were analyzed by linear regression, as well as comparisons between these trends. Results: there was an inverse correlation between SI and hospitalizations for CVD (R2 = 0.70; p < 0.001), IHD (R2 = 0.70; p < 0.001), and stroke (R2 = 0.39; p < 0.001). The most significant hospitalization reduction was from March to May, when the SI increased from 43.07% to 50.71%. The increase in SI was also associated with a reduction in CVD deaths (R2 = 0.49; p < 0.001), IHD (R2 = 0.50; p < 0.001), and stroke (R2 = 0.26; p < 0.001). Conclusions: Increased social isolation was associated with reduced hospitalizations and deaths from CVD, IHD, and stroke. Full article
(This article belongs to the Special Issue Epidemiology and Public Healthcare Systems during COVID-19)
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12 pages, 2333 KiB  
Article
Dengue Infections during COVID-19 Period: Reflection of Reality or Elusive Data Due to Effect of Pandemic
by Sakirul Khan, Sheikh Mohammad Fazle Akbar, Takaaki Yahiro, Mamun Al Mahtab, Kazunori Kimitsuki, Takehiro Hashimoto and Akira Nishizono
Int. J. Environ. Res. Public Health 2022, 19(17), 10768; https://doi.org/10.3390/ijerph191710768 - 29 Aug 2022
Cited by 19 | Viewed by 3227
Abstract
The outbreak of coronavirus disease 2019 (COVID-19) devastated the overall health management strategy of most countries. In this scenario, the present study provided insights into the possible impact of the COVID-19 pandemic on dengue infection. This ecological study retrieved data from WHO/Government reporting [...] Read more.
The outbreak of coronavirus disease 2019 (COVID-19) devastated the overall health management strategy of most countries. In this scenario, the present study provided insights into the possible impact of the COVID-19 pandemic on dengue infection. This ecological study retrieved data from WHO/Government reporting system from 22 major dengue epidemic countries. Incidence of dengue infections during the pre-COVID-19 time (2015~2019) and COVID-19 period (2020~2021) was compared. A correlation between the dengue and COVID-19 cases and predicted dengue incidence in 2022 was calculated using the linear regression equation. Data indicated that dengue incidences across the studied area decreased by 16% during the pandemic period (2.73 million vs. 2.29 million; p < 0.05) than the same reported in pre-COVID-19 time. Although countries in Latin America reported more cases than Asia, a positive correlation (r = 0.83) between dengue and COVID-19 cases was observed in Asia. Prediction analysis warned that specific preparation for dengue management is needed in some countries of both regions in 2022 to contain the upsurge in incidences. Due to the similar nature of symptoms of dengue and COVID-19, a state of confusion will be prevailing during the ongoing pandemic. Therefore, comprehensive and evidence-based scientific approaches were warranted at all levels. Full article
(This article belongs to the Special Issue Epidemiology and Public Healthcare Systems during COVID-19)
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11 pages, 552 KiB  
Article
Increased Secondary Attack Rates among the Household Contacts of Patients with the Omicron Variant of the Coronavirus Disease 2019 in Japan
by Tsuyoshi Ogata, Hideo Tanaka, Emiko Tanaka, Natsumi Osaki, Etsuko Noguchi, Yukino Osaki, Ayane Tono and Koji Wada
Int. J. Environ. Res. Public Health 2022, 19(13), 8068; https://doi.org/10.3390/ijerph19138068 - 30 Jun 2022
Cited by 14 | Viewed by 3111
Abstract
This study investigated the household secondary attack rate (HSAR) of patients with coronavirus disease (COVID-19) during the omicron variant-dominant period. The HSAR of COVID-19 cases during the omicron variant-dominant period (4–20 January 2022) was calculated and compared with the delta variant-dominant period (20 [...] Read more.
This study investigated the household secondary attack rate (HSAR) of patients with coronavirus disease (COVID-19) during the omicron variant-dominant period. The HSAR of COVID-19 cases during the omicron variant-dominant period (4–20 January 2022) was calculated and compared with the delta variant-dominant period (20 August to 7 November 2021) in Itako, Japan. In Itako, all 47 and 119 samples tested during the omicron and delta variant-dominant periods were negative and positive, respectively, for the L452R mutation. We used a generalized estimating equation regression model. The HSAR was 31.8% (95% confidence interval (CI) 27.7–36.2) for 456 household contacts during the omicron variant-dominant period; it was higher than that during the delta variant-dominant period (25.2%) (adjusted risk ratio [aRR] 1.61, CI 1.13–2.28). During the omicron variant-dominant period, HSAR was lower for the household contacts of completely vaccinated index patients (27.3%) than for contacts of other index patients (41.2%) (vaccine effectiveness for infectee 0.43, 95% CI 0.16–0.62) and was significantly higher for female contacts than for male contacts (36.2% vs. 26.1%; aRR 1.29, 95% CI 1.01–1.65). The HSAR was significantly higher during the omicron variant-dominant period than the delta variant-dominant period. The vaccination of index patients might protect household contacts. Full article
(This article belongs to the Special Issue Epidemiology and Public Healthcare Systems during COVID-19)
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7 pages, 1102 KiB  
Article
Shorter Incubation Period among COVID-19 Cases with the BA.1 Omicron Variant
by Hideo Tanaka, Tsuyoshi Ogata, Toshiyuki Shibata, Hitomi Nagai, Yuki Takahashi, Masaru Kinoshita, Keisuke Matsubayashi, Sanae Hattori and Chie Taniguchi
Int. J. Environ. Res. Public Health 2022, 19(10), 6330; https://doi.org/10.3390/ijerph19106330 - 23 May 2022
Cited by 42 | Viewed by 22465
Abstract
We aimed to elucidate the range of the incubation period in patients infected with the SARS-CoV-2 Omicron variant in comparison with the Alpha variant. Contact tracing data from three Japanese public health centers (total residents, 1.06 million) collected following the guidelines of the [...] Read more.
We aimed to elucidate the range of the incubation period in patients infected with the SARS-CoV-2 Omicron variant in comparison with the Alpha variant. Contact tracing data from three Japanese public health centers (total residents, 1.06 million) collected following the guidelines of the Infectious Diseases Control Law were reviewed for 1589 PCR-confirmed COVID-19 cases diagnosed in January 2022. We identified 77 eligible symptomatic patients for whom the date and setting of transmission were known, in the absence of any other probable routes of transmission. The observed incubation period was 3.03 ± 1.35 days (mean ± SDM). In the log-normal distribution, 5th, 50th and 95th percentile values were 1.3 days (95% CI: 1.0–1.6), 2.8 days (2.5–3.1) and 5.8 days (4.8–7.5), significantly shorter than among the 51 patients with the Alpha variant diagnosed in April and May in 2021 (4.94 days ± 2.19, 2.1 days (1.5–2.7), 4.5 days (4.0–5.1) and 9.6 days (7.4–13.0), p < 0.001). As this incubation period, mainly of sublineage BA.1, is even shorter than that in the Delta variant, it is thought to partially explain the variant replacement occurring in late 2021 to early 2022 in many countries. Full article
(This article belongs to the Special Issue Epidemiology and Public Healthcare Systems during COVID-19)
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7 pages, 330 KiB  
Article
Detection of SARS-CoV-2 in the Indoor and Outdoor Areas of Urban Public Transport Systems of Three Major Cities of Portugal in 2021
by Priscilla Gomes da Silva, José Gonçalves, Maria São José Nascimento, Sofia I. V. Sousa and João R. Mesquita
Int. J. Environ. Res. Public Health 2022, 19(10), 5955; https://doi.org/10.3390/ijerph19105955 - 13 May 2022
Cited by 9 | Viewed by 2374
Abstract
Airborne transmission is mainly associated with poorly ventilated and crowded indoor environments where people stay for long periods of time. As such, public transport is often perceived as having a high risk for the transmission of SARS-CoV-2. Considering that data on the detection [...] Read more.
Airborne transmission is mainly associated with poorly ventilated and crowded indoor environments where people stay for long periods of time. As such, public transport is often perceived as having a high risk for the transmission of SARS-CoV-2. Considering that data on the detection of SARS-CoV-2 in public transport systems are scarce, we performed air sampling for SARS-CoV-2 in indoor and outdoor spaces of public transport systems in Portugal. Air (n = 31) and surface (n = 70) samples were collected using a Coriolis® Compact microbial air sampler and sterile flocked plastic swabs, respectively. Samples were extracted and analyzed through RT-qPCR. Only two air samples from an outdoor and a partially open space were found to be positive for SARS-CoV-2 RNA. No positive surface samples were detected. These results indicate that the viral concentration in ambient air in public transport systems is linked to the number of people present in that environment and whether they are wearing properly fitting masks. Considering the current lifting of COVID-19 restrictions around the world, it is essential that people continue to wear masks in both indoor and outdoor environments, especially in crowded spaces. More studies on this topic are needed to fully elucidate the real risk of infection in outdoor spaces. Full article
(This article belongs to the Special Issue Epidemiology and Public Healthcare Systems during COVID-19)
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11 pages, 321 KiB  
Article
Increased Secondary Attack Rate among Unvaccinated Household Contacts of Coronavirus Disease 2019 Patients with Delta Variant in Japan
by Tsuyoshi Ogata, Hideo Tanaka, Yumiko Nozawa, Kazue Mukouyama, Emiko Tanaka, Natsumi Osaki, Etsuko Noguchi, Kayoko Seo and Koji Wada
Int. J. Environ. Res. Public Health 2022, 19(7), 3889; https://doi.org/10.3390/ijerph19073889 - 24 Mar 2022
Cited by 8 | Viewed by 2724
Abstract
This study aimed to elucidate the household secondary attack rate (HSAR) of the Delta variant in comparison to the Alpha variant, and evaluate the risk factors among unvaccinated household contacts of patients with coronavirus disease 2019 (COVID-19). We studied household contacts of index [...] Read more.
This study aimed to elucidate the household secondary attack rate (HSAR) of the Delta variant in comparison to the Alpha variant, and evaluate the risk factors among unvaccinated household contacts of patients with coronavirus disease 2019 (COVID-19). We studied household contacts of index cases of COVID-19 infected with Delta (L452R mutation), Alpha (N501Y mutation), and wild strain from December 2020 through November 2021 in Itako, Japan. The HSARs of the entire household contact, and the contact of index case with Delta variant were calculated and compared across the risk factors. We used a generalized estimating equation regression model for the multivariate analysis. We enrolled 1257 unvaccinated contacts from 580 households. The HSAR was higher in household contacts of index patients with Delta (48.5%) than with Alpha variant (21.7%) (aOR = 3.34, p = 0.000). In Delta variants, the HSAR was higher in household contacts with spousal relationships to index patients (63.4%) than contacts with other relationships (45.5%) (aOR 1.94, p = 0.026), and was lower in household contacts of index patients aged ≤19 (33.1%) than for contacts of index cases aged 20–59 years (52.6%) (aOR = 0.50, p = 0.027). The result of our study can be used to devise informed strategy to prevent transmission within households. Full article
(This article belongs to the Special Issue Epidemiology and Public Healthcare Systems during COVID-19)
15 pages, 1859 KiB  
Article
Shorter Incubation Period among Unvaccinated Delta Variant Coronavirus Disease 2019 Patients in Japan
by Tsuyoshi Ogata, Hideo Tanaka, Fujiko Irie, Atsushi Hirayama and Yuki Takahashi
Int. J. Environ. Res. Public Health 2022, 19(3), 1127; https://doi.org/10.3390/ijerph19031127 - 20 Jan 2022
Cited by 25 | Viewed by 7537
Abstract
Few studies have assessed incubation periods of the severe acute respiratory syndrome coronavirus 2 Delta variant. This study aimed to elucidate the transmission dynamics, especially the incubation period, for the Delta variant compared with non-Delta strains. We studied unvaccinated coronavirus disease 2019 patients [...] Read more.
Few studies have assessed incubation periods of the severe acute respiratory syndrome coronavirus 2 Delta variant. This study aimed to elucidate the transmission dynamics, especially the incubation period, for the Delta variant compared with non-Delta strains. We studied unvaccinated coronavirus disease 2019 patients with definite single exposure date from August 2020 to September 2021 in Japan. The incubation periods were calculated and compared by Mann–Whitney U test for Delta (with L452R mutation) and non-Delta cases. We estimated mean and percentiles of incubation period by fitting parametric distribution to data in the Bayesian statistical framework. We enrolled 214 patients (121 Delta and 103 non-Delta cases) with one specific date of exposure to the virus. The mean incubation period was 3.7 days and 4.9 days for Delta and non-Delta cases, respectively (p-value = 0.000). When lognormal distributions were fitted, the estimated mean incubation periods were 3.7 (95% credible interval (CI) 3.4–4.0) and 5.0 (95% CI 4.5–5.6) days for Delta and non-Delta cases, respectively. The estimated 97.5th percentile of incubation period was 6.9 (95% CI 5.9–8.0) days and 10.4 (95% CI 8.6–12.7) days for Delta and non–Delta cases, respectively. Unvaccinated Delta variant cases had shorter incubation periods than non–Delta variant cases. Full article
(This article belongs to the Special Issue Epidemiology and Public Healthcare Systems during COVID-19)
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Review

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14 pages, 1875 KiB  
Review
Reliability of Early Estimates of the Basic Reproduction Number of COVID-19: A Systematic Review and Meta-Analysis
by Bibha Dhungel, Md. Shafiur Rahman, Md. Mahfuzur Rahman, Aliza K. C. Bhandari, Phuong Mai Le, Nushrat Alam Biva and Stuart Gilmour
Int. J. Environ. Res. Public Health 2022, 19(18), 11613; https://doi.org/10.3390/ijerph191811613 - 15 Sep 2022
Cited by 4 | Viewed by 3455
Abstract
Objective: This systematic review estimated the pooled R0 for early COVID-19 outbreaks and identified the impact of study-related factors such as methods, study location and study period on the estimated R0. Methods: We searched electronic databases for human studies published [...] Read more.
Objective: This systematic review estimated the pooled R0 for early COVID-19 outbreaks and identified the impact of study-related factors such as methods, study location and study period on the estimated R0. Methods: We searched electronic databases for human studies published in English between 1 December 2019 and 30 September 2020 with no restriction on country/region. Two investigators independently performed the data extraction of the studies selected for inclusion during full-text screening. The primary outcome, R0, was analysed by random-effects meta-analysis using the restricted maximum likelihood method. Results: We identified 26,425 studies through our search and included 151 articles in the systematic review, among which 81 were included in the meta-analysis. The estimates of R0 from studies included in the meta-analysis ranged from 0.4 to 12.58. The pooled R0 for COVID-19 was estimated to be 2.66 (95% CI, 2.41–2.94). The results showed heterogeneity among studies and strong evidence of a small-study effect. Conclusions: The high heterogeneity in studies makes the use of the R0 for basic epidemic planning difficult and presents a huge problem for risk assessment and data synthesis. Consensus on the use of R0 for outbreak assessment is needed, and its use for assessing epidemic risk is not recommended. Full article
(This article belongs to the Special Issue Epidemiology and Public Healthcare Systems during COVID-19)
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12 pages, 1391 KiB  
Review
Prevalence of Coronavirus Disease 2019 (COVID-19) in Different Clinical Stages before the National COVID-19 Vaccination Programme in Malaysia: A Systematic Review and Meta-Analysis
by Jun Wei Ng, Eric Tzyy Jiann Chong, Yee Ann Tan, Heng Gee Lee, Lan Lan Chan, Qin Zhi Lee, Yen Tsen Saw, Yiko Wong, Ahmad Aizudeen Bin Zakaria, Zarina Binti Amin and Ping-Chin Lee
Int. J. Environ. Res. Public Health 2022, 19(4), 2216; https://doi.org/10.3390/ijerph19042216 - 16 Feb 2022
Cited by 11 | Viewed by 3665
Abstract
More than 1.75 million COVID-19 infections and 16 thousand associated deaths have been reported in Malaysia. A meta-analysis on the prevalence of COVID-19 in different clinical stages before the National COVID-19 Vaccination Program in Malaysia is still lacking. To address this, the disease [...] Read more.
More than 1.75 million COVID-19 infections and 16 thousand associated deaths have been reported in Malaysia. A meta-analysis on the prevalence of COVID-19 in different clinical stages before the National COVID-19 Vaccination Program in Malaysia is still lacking. To address this, the disease severity of a total of 215 admitted COVID-19 patients was initially recorded in the early phase of this study, and the data were later pooled into a meta-analysis with the aim of providing insight into the prevalence of COVID-19 in 5 different clinical stages during the outset of the COVID-19 pandemic in Malaysia. We have conducted a systematic literature search using PubMed, Web of Science, Scopus, ScienceDirect, and two preprint databases (bioRxiv and medRxiv) for relevant studies with specified inclusion and exclusion criteria. The quality assessment for the included studies was performed using the Newcastle–Ottawa Scale. The heterogeneity was examined with an I2 index and a Q-test. Funnel plots and Egger’s tests were performed to determine publication bias in this meta-analysis. Overall, 5 studies with 6375 patients were included, and the pooled prevalence rates in this meta-analysis were calculated using a random-effect model. The highest prevalence of COVID-19 in Malaysia was observed in Stage 2 cases (32.0%), followed by Stage 1 (27.8%), Stage 3 (17.1%), Stage 4 (7.6%), and Stage 5 (3.4%). About two-thirds of the number of cases have at least one morbidity, with the highest percentage of hypertension (66.7%), obesity (55.5%), or diabetes mellitus (33.3%) in Stage 5 patients. In conclusion, this meta-analysis suggested a high prevalence of COVID-19 occurred in Stage 2. The prevalence rate in Stage 5 appeared to be the lowest among COVID-19 patients before implementing the vaccination program in Malaysia. These meta-analysis data are critically useful for designing screening and vaccination programs and improving disease management in the country. Full article
(This article belongs to the Special Issue Epidemiology and Public Healthcare Systems during COVID-19)
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8 pages, 1126 KiB  
Brief Report
Properties of the Omicron Variant of SARS-CoV-2 Affect Public Health Measure Effectiveness in the COVID-19 Epidemic
by Yuki Furuse
Int. J. Environ. Res. Public Health 2022, 19(9), 4930; https://doi.org/10.3390/ijerph19094930 - 19 Apr 2022
Cited by 5 | Viewed by 3425
Abstract
Nonpharmaceutical and pharmaceutical public health interventions are important to mitigate the coronavirus disease 2019 (COVID-19) epidemic. However, it is still unclear how the effectiveness of these interventions changes with the emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) novel variants. This simulation [...] Read more.
Nonpharmaceutical and pharmaceutical public health interventions are important to mitigate the coronavirus disease 2019 (COVID-19) epidemic. However, it is still unclear how the effectiveness of these interventions changes with the emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) novel variants. This simulation study utilized data from Japan and investigated how the characteristic properties of the Omicron variant, which emerged in late 2021, influence the effectiveness of public health interventions, including vaccination, the reduction of interpersonal contact, and the early isolation of infectious people. Although the short generation time of the Omicron variant increases the effectiveness of vaccination and the reduction of interpersonal contact, it decreases the effectiveness of early isolation. The latter feature may make the containment of case clusters difficult. The increase of infected children during the Omicron-dominant epidemic diminishes the effects of previously adult-targeted interventions. These findings underscore the importance of monitoring viral evolution and consequent changes in epidemiological characteristics. An assessment and adaptation of public health measures against COVID-19 are required as SARS-CoV-2 novel variants continue to emerge. Full article
(This article belongs to the Special Issue Epidemiology and Public Healthcare Systems during COVID-19)
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