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While the efficacy of coronavirus disease 2019 (COVID-19) vaccines has been evaluated in numerous trials, comprehensive evidence on how protection by different vaccines has varied over time remains limited. We aimed to compare protective effects of different vaccines against different viral variants. To achieve this, we searched Medline, Cochrane Library and Embase for randomized controlled trials assessing the efficacy of COVID-19 vaccines. Forest plots using Mantel-Haenszel and random-effects models were generated showing risk ratios (RRs) and 95% CIs by vaccines and variants. We included 36 studies with 90 variant-specific primary outcomes. We found a RR of 0.26 (95% CI 0.21 to 0.31) against all variants overall, with the highest protective effects against the wild-type (RR 0.13; 95% CI 0.10 to 0.18), followed by Alpha (RR 0.26; 95% CI 0.18 to 0.36), Gamma (RR 0.34; 95% CI 0.21 to 0.55), Delta (RR 0.39; 95% CI 0.28 to 0.56) and Beta (RR 0.49; 95% CI 0.40 to 0.62) variants. Nucleic acid vaccines showed the highest protection levels against all variants (RR 0.11; 95% CI 0.08 to 0.15), followed by protein subunit, inactivated virus and viral vector. In conclusion, we found high but heterogenous levels of protection for most COVID-19 vaccines, with decreasing protective effects for vaccines based on traditional technologies as SARS-CoV-2 variants emerged over time. Novel nucleic acid-based vaccines offered substantially higher and more consistent protection., (© The Author(s) 2024. Published by Oxford University Press on behalf of Royal Society of Tropical Medicine and Hygiene.)

Survivors of COVID-19 are susceptible to diminished health-related quality of life (HRQoL) and adverse psychological health, which may be exacerbated by their experiences of fear and the impact of the pandemic itself. This study aims to identify distinct fear and impact patterns related to the COVID-19 pandemic among survivors through latent profile analysis (LPA) and examine the associations of fear and impact patterns with post-traumatic stress symptoms (PTSS) and HRQoL. A total of 5,890 Vietnamese COVID-19 survivors completed the COVID-19 Impact Battery- Disability Scale (CIB-D), the Fear of COVID-19 Scale (FCoV-19 S), the Impact of Event Scale-Revised for PTSS, and the 36-Item Short Form Survey (SF-36) for HRQoL. Four distinct groups of fear and impact were identified: "Fearful and highly impacted" (26.8%), "moderately impacted yet not fearful" (22.9%), "less impacted and less fearful" (18.6%), and "mildly impacted and neutral" (31.7%). Survivors who were "less impacted and less fearful" exhibited significantly higher HRQoL scores (regression coefficient, B: 10.9; 95% confidence interval (CI): 10.0 - 11.7), both in terms of physical (B: 12.0; 95%CI: 11.1 - 12.9) and mental health (B: 19.4; 95%CI: 9.6 - 11.1), and lower PTSS levels (B: -24.5; 95%CI: -25.8 - -23.3) compared to those who were "highly impacted and fearful". It is imperative to acknowledge the intricate association between fear, impact, and mental health to comprehensively address the diverse needs of this distinct population post-COVID-19. These findings provide insights for designing interventions and support mechanisms for COVID-19 survivors., Competing Interests: Declarations. Ethics Approval and Consent to Participate: The study protocol received approval from the Institutional Ethical Review Committee of Hanoi University of Public Health (No. 400/2021/YTCC-HD3 and 45/2022/YTCC-HD3). All participants gave consent online consent after receiving information about the study and before joining the survey. Consent for Publication: This study is approved by the respective ethics review board for publication. All authors approve this manuscript for submission and publication. Competing Interests: The authors declare no competing interests., (© 2024. The Author(s).)

Background: The COVID-19 pandemic has underscored the significance of adopting healthy lifestyles to mitigate the risk of severe outcomes and long-term consequences., Objective: This study focuses on assessing the prevalence and clustering of 5 unhealthy lifestyle behaviors among Vietnamese adults after recovering from COVID-19, with a specific emphasis on sex differences., Methods: The cross-sectional data of 5890 survivors of COVID-19 in Vietnam were analyzed from December 2021 to October 2022. To examine the sex differences in 5 unhealthy lifestyle behaviors (smoking, drinking, unhealthy diet, physical inactivity, and sedentary behavior), the percentages were plotted along with their corresponding 95% CI for each behavior. Latent class analysis was used to identify 2 distinct classes of individuals based on the clustering of these behaviors: the "less unhealthy" group and the "more unhealthy" group. We examined the sociodemographic characteristics associated with each identified class and used logistic regression to investigate the factors related to the "more unhealthy" group., Results: The majority of individuals (male participants: 2432/2447, 99.4% and female participants: 3411/3443, 99.1%) exhibited at least 1 unhealthy behavior, with male participants being more susceptible to multiple unhealthy behaviors. The male-to-female ratio for having a single behavior was 1.003, but it escalated to 25 for individuals displaying all 5 behaviors. Male participants demonstrated a higher prevalence of combining alcohol intake with sedentary behavior (949/2447, 38.8%) or an unhealthy diet (861/2447, 35.2%), whereas female participants tended to exhibit physical inactivity combined with sedentary behavior (1305/3443, 37.9%) or an unhealthy diet (1260/3443, 36.6%). Married male participants had increased odds of falling into the "more unhealthy" group compared to their single counterparts (odds ratio [OR] 1.45, 95% CI 1.14-1.85), while female participants exhibited lower odds (OR 0.65, 95% CI 0.51-0.83). Female participants who are underweight showed a higher likelihood of belonging to the "more unhealthy" group (OR 1.11, 95% CI 0.89-1.39), but this was not observed among male participants (OR 0.6, 95% CI 0.41-0.89). In both sexes, older age, dependent employment, high education, and obesity were associated with higher odds of being in the "more unhealthy" group., Conclusions: The study identified notable sex differences in unhealthy lifestyle behaviors among survivors of COVID-19. Male survivors are more likely to engage in unhealthy behaviors compared to female survivors. These findings emphasize the importance of tailored public health interventions targeting sex-specific unhealthy behaviors. Specifically, addressing unhealthy habits is crucial for promoting post-COVID-19 health and well-being., (©Lan T H Le, Thi Ngoc Anh Hoang, Tan T Nguyen, Tien D Dao, Binh N Do, Khue M Pham, Vinh H Vu, Linh V Pham, Lien T H Nguyen, Hoang C Nguyen, Tuan V Tran, Trung H Nguyen, Anh T Nguyen, Hoan V Nguyen, Phuoc B Nguyen, Hoai T T Nguyen, Thu T M Pham, Thuy T Le, Thao T P Nguyen, Cuong Q Tran, Ha-Linh Quach, Kien T Nguyen, Tuyen Van Duong. Originally published in JMIR Public Health and Surveillance (https://publichealth.jmir.org), 02.04.2024.)

Background: In 2022, many universities transitioned from virtual learning back to in-person teaching. Significant changes in working conditions, along with COVID-19-related anxiety during the pandemic, might impact the well-being of lecturers., Objective: This study aims to assess the perceived stress, self-rated physical and occupational health of Vietnamese lecturers in 2022 compared to the pre-pandemic levels, and to identify their associating factors., Method: This is a cross-sectional study conducted in May-June 2022 through an online survey questionnaire. A sample of 425 university lecturers were included. Participants' stress levels were assessed using the Perceived Stress Scale. Participants were asked to compare their current physical and occupational health with before the pandemic. Explanatory variables included (1) COVID-19 exposure; and (2) perceptions of changes in working environment due to the pandemic. Multivariable ordinal least squared regression analyses were used to estimate the coefficient and 95% confidence intervals for the associations between COVID-19 exposure variables, work conditions, and each outcome., Results: Our findings indicated that over 60% of participants experienced moderate stress, while nearly half reported worsened physical and occupational health during the pandemic. Gender, age, perceptions of workload, workplace safety, COVID-19 infection, and incentive programs were significant factors associated with higher stress levels and worse self-rated health., Conclusion: To ensure occupational safety and support lecturers as they return to in-person classes, it is crucial to provide appropriate psychological and health support services.

BackgroundVaccines play a crucial role in the response to COVID-19 and their efficacy is thus of great importance.AimTo assess the robustness of COVID-19 vaccine efficacy (VE) trial results using the fragility index (FI) and fragility quotient (FQ) methodology.MethodsWe conducted a Cochrane and PRISMA-compliant systematic review and meta-analysis of COVID-19 VE trials published worldwide until 22 January 2023. We calculated the FI and FQ for all included studies and assessed their associations with selected trial characteristics using Wilcoxon rank sum tests and Kruskal-Wallis H tests. Spearman correlation coefficients and scatter plots were used to quantify the strength of correlation of FIs and FQs with trial characteristics.ResultsOf 6,032 screened records, we included 40 trials with 54 primary outcomes, comprising 909,404 participants with a median sample size per outcome of 13,993 (interquartile range (IQR): 8,534-25,519). The median FI and FQ was 62 (IQR: 22-123) and 0.50% (IQR: 0.24-0.92), respectively. FIs were positively associated with sample size (p < 0.001), and FQs were positively associated with type of blinding (p = 0.023). The Spearman correlation coefficient for FI with sample size was moderately strong (0.607), and weakly positive for FI and FQ with VE (0.138 and 0.161, respectively).ConclusionsThis was the largest study on trial robustness to date. Robustness of COVID-19 VE trials increased with sample size and varied considerably across several other important trial characteristics. The FI and FQ are valuable complementary parameters for the interpretation of trial results and should be reported alongside established trial outcome measures.

Surveillance is the backbone of any response to an infectious disease outbreak, and comprehensive evaluation of surveillance systems is crucial. However, structured evaluations of surveillance systems during the COVID-19 pandemic are scarce. We conducted a after action review (AAR) of the performance of the COVID-19 surveillance system in Quang Ninh Province, Vietnam, during 2020 using the COVID-19-specific AAR methodology developed by the World Health Organization in combination with guidance from the US Centers for Disease Control and Prevention (CDC). We conducted a stakeholder survey, document reviews, and key informant interviews with staff from Quang Ninh CDC's COVID-19 surveillance system. The COVID-19 surveillance system was based on the pre-existing surveillance system in the province. The system's strengths were early preparation for emergency response, strong governance and central coordination, and multidisciplinary collaboration. Stakeholders agreed that the system proved useful and adaptive to the fast-evolving COVID-19 situation but was weakened by overly complex systems, redundant administrative processes, unclear communication channels, and lack of resources. Overall, the surveillance systems in Quang Ninh province proved effective in containing COVID-19 and adaptive in a fast-changing epidemiological context. Several recommendations were made based on identified areas of concern that are of relevance for COVID-19 surveillance systems in Vietnam and similar settings.

Objectives: In March 2020, a COVID-19 outbreak in a major referral hospital in Hanoi, Vietnam led to 7664 patients and staff being sent into lockdown for 2 weeks, and more than 52,200 persons across 49 provinces being quarantined. We assessed SARS-CoV-2 transmission patterns during this to-date largest hospital outbreak in Vietnam using social network analysis (SNA)., Methods: We constructed a directed relational network and calculated network metrics for 'degree', 'betweenness', 'closeness' and 'eigenvector' centrality to understand individual-level transmission patterns. We analysed network components and modularity to identify sub-network structures with disproportionately big effects., Results: We detected 68 connections between 46 confirmed cases, of whom 27 (58.7%) were ancillary support staff, 7 (15.2%) caregivers, 6 (13%) patients and 2 (4.4%) nurses. Among the 10 most important cases selected by each SNA network metric, transmission dynamics clustered in 17 cases, of whom 12 (70.6%) cases were ancillary support staff. Ancillary support staff also constituted 71.1% of cases in the dominant sub-network and 68.8% of cases in the three largest sub-communities., Conclusions: We identified non-clinical ancillary support staff, who are responsible for room service and food distribution in hospital wards in Vietnam, as a group with disproportionally big impacts on transmission dynamics during this outbreak. Our findings call for a holistic approach to nosocomial outbreak prevention and response that includes both clinical and non-clinical hospital staff. Our work also shows the potential of SNA as a complementary outbreak investigation method to better understand infection patterns in hospitals and similar settings., (© 2022 John Wiley & Sons Ltd.)

Background: Community health workers (CHWs) involved in the COVID-19 response might be at increased risk of developing depression, though evidence is scarce. We investigated effects of COVID-19-related work on changes in depression levels among CHWs in Vietnam and identified sub-groups among CHWs who are at particular risk of developing severe depression., Methods: We conducted a cross-sectional online survey among 979 CHWs who were involved in the COVID-19 response in Vietnam, in particular during the 2021 Tet holiday outbreak between January and March 2021. Respondents were asked to report depression symptoms at two-time points, before the start of the COVID-19 pandemic (average June to December 2019) and during the 2021 Tet holiday outbreak using the PHQ-9 mental health questionnaire. We estimated depression levels at both time points and developed univariate and multivariable logistic regression models to estimate odds ratios and 95% confidence intervals (95% CIs) to explore the association between deterioration to high depression levels and selected risk factors., Results: Median depression levels among CHWs in Vietnam doubled from 3 (IQR = 2-7) before COVID-19 to 6 (IQR = 3-9) on the PHQ-9 scale during the Tet holiday outbreak. The proportion with normal/minimal levels decreased from 77.1% (95% CI = 74.4-79.7) to 50.9% (95% CI = 47.7-54) (p-value < 0.001), while the proportion of CHWs with moderate, moderately severe, and severe depression levels increased 4.3, 4.5, and five-fold, respectively. Less sleep and poor sleep quality, working in unfavorable work environments, and being involved in contact tracing and the organization of quarantine for suspected cases were associated with an increased risk of deterioration to high depression levels., Conclusions: We found a substantial increase in overall depression levels among CHWs in Vietnam due to their COVID-19 related work and a particularly worrisome rise in CHWs suffering from severe depression. CHWs are an indispensable yet often overlooked cadre of work in many low- and middle-income countries and shoulder a heavy psychological burden during the COVID-19 pandemic. Targeted psychological support for CHWs is needed to improve their mental health and to ensure the sustainability of community-based health interventions during COVID-19 and future epidemics., (© 2022. The Author(s).)

Background: Trends in the public perception and awareness of COVID-19 over time are poorly understood. We conducted a longitudinal study to analyze characteristics and trends of online information during a major COVID-19 outbreak in Da Nang province, Vietnam in July-August 2020 to understand public awareness and perceptions during an epidemic., Methods: We collected online information on COVID-19 incidence and mortality from online platforms in Vietnam between 1 July and 15 September, 2020, and assessed their trends over time against the epidemic curve. We explored the associations between engagement, sentiment polarity, and other characteristics of online information with different outbreak phases using Poisson regression and multinomial logistic regression analysis. We assessed the frequency of keywords over time, and conducted a semantic analysis of keywords using word segmentation., Results: We found a close association between collected online information and the evolution of the COVID-19 situation in Vietnam. Online information generated higher engagements during compared to before the outbreak. There was a close relationship between sentiment polarity and posts' topics: the emotional tendencies about COVID-19 mortality were significantly more negative, and more neutral or positive about COVID-19 incidence. Online newspaper reported significantly more information in negative or positive sentiment than online forums or social media. Most topics of public concern followed closely the progression of the COVID-19 situation during the outbreak: development of the global pandemic and vaccination; the unfolding outbreak in Vietnam; and the subsiding of the outbreak after two months., Conclusion: This study shows how online information can reflect a public health threat in real time, and provides important insights about public awareness and perception during different outbreak phases. Our findings can help public health decision makers in Vietnam and other low and middle income countries with high internet penetration rates to design more effective communication strategies during critical phases of an epidemic., Competing Interests: The authors have declared that no competing interests exist.

Objective: Asymptomatic infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and test re-positivity after a negative test have raised concerns about the ability to effectively control the coronavirus disease 2019 (COVID-19) pandemic. We aimed to investigate the prevalence of COVID-19 asymptomatic and pre-symptomatic infections during the second wave of COVID-19 in Viet Nam, and to better understand the duration of SARS-CoV-2 infection and the dynamics between the evolution of clinical symptoms and SARS-CoV-2 test positivity among confirmed COVID-19 cases., Methods: We conducted a cohort analysis on the first 50 confirmed cases during the second COVID-19 wave in Viet Nam using clinical, laboratory and epidemiological data collected from 9 March to 30 April 2020. Kaplan-Meier estimates were used to assess time to clearance of SARS-CoV-2 infection, and log-rank tests were used to explore factors related to time to SARS-CoV-2 infection clearance., Results: Most cases (58%) had no typical signs or symptoms of COVID-19 at the time of diagnosis. Ten cases (20%) were re-positive for SARS-CoV-2 during infection. Eight cases (16%) experienced COVID-19 symptoms after testing negative for SARS-CoV-2. The median duration from symptom onset until clearance of infection was 14 days (range: 6-31); it was longer in re-positive and older patients and those with pre-existing conditions., Conclusion: Asymptomatic and pre-symptomatic infections were common during the second wave of COVID-19 in Viet Nam. Re-positivity was frequent during hospitalization and led to a long duration of SARS-CoV-2 infection., ((c) 2021 The authors; licensee World Health Organization.)

Background: Vietnam implemented various public health interventions such as contact tracing and testing, mandatory quarantine, and lockdowns in response to coronavirus disease 2019 (COVID-19). However, the effects of these measures on the epidemic remain unclear., Methods: This article describes the public health interventions in relation to COVID-19 incidence. Maximum likelihood estimations were used to assess containment delays (time between symptom onset and start of isolation) and multivariable regression was employed to identify associated factors between interventions and COVID-19 incidence. The effective reproductive numbers (Rt) were calculated based on transmission pairs., Results: Interventions were introduced periodically in response to the epidemic. Overall, 817 (55.4%) among 1474 COVID-19 cases were imported. Based on a serial interval of 8.72 ± 5.65 days, it was estimated that Rt decreased to below 1 (lowest at 0.02, 95% CI 0-0.12) during periods of strict border control and contact tracing, and increased ahead of new clusters. The main method to detect cases shifted over time from passive notification to active case-finding at immigration or in lockdown areas, with containment delays showing significant differences between modes of case detection., Conclusions: A combination of early, strict, and consistently implemented interventions is crucial to control COVID-19. Low-middle income countries with limited capacity can contain COVID-19 successfully using non-pharmaceutical interventions., (Copyright © 2021 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Background: The importation of SARS-CoV-2 through air travel poses substantial risks to generate new COVID-19 outbreaks. Timely contact tracing is particularly crucial to limit onwards transmission in settings without established community transmission., Methods: We conducted an in-depth analysis of the response to a big flight-associated COVID-19 outbreak in Vietnam in March 2020 that involved contact tracing, systematic testing and strict quarantine up to third generation contacts., Results: 183 primary contacts from the flight as well as 1000 secondary and 311 third generation contacts were traced, tested, and quarantined across 15 provinces across Vietnam. The protracted confirmation of the index case at 3 days and 19 h after arrival resulted in isolation/quarantine delays of 6.8 days (IQR 6.3-6.8) and 5.8 days (IQR 5.8-7.0) for primary and secondary cases, respectively, which generated 84.0 and 26.4 person-days of community exposure from primary and secondary cases, respectively. Nevertheless, only 5 secondary cases occurred., Conclusions: A large flight-related COVID-19 cluster was successfully contained through timely, systematic and comprehensive public health responses despite delayed index case identification. Multiagency collaboration and pre-established mechanisms are crucial for low and middle income countries like Vietnam to limit community transmission after COVID-19 importation through air travel., (Copyright © 2021 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Background: One hundred days after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was first reported in Vietnam on 23 January, 270 cases were confirmed, with no deaths. We describe the control measures used by the government and their relationship with imported and domestically acquired case numbers, with the aim of identifying the measures associated with successful SARS-CoV-2 control., Methods: Clinical and demographic data on the first 270 SARS-CoV-2 infected cases and the timing and nature of government control measures, including numbers of tests and quarantined individuals, were analyzed. Apple and Google mobility data provided proxies for population movement. Serial intervals were calculated from 33 infector-infectee pairs and used to estimate the proportion of presymptomatic transmission events and time-varying reproduction numbers., Results: A national lockdown was implemented between 1 and 22 April. Around 200 000 people were quarantined and 266 122 reverse transcription polymerase chain reaction (RT-PCR) tests conducted. Population mobility decreased progressively before lockdown. In total, 60% (163/270) of cases were imported; 43% (89/208) of resolved infections remained asymptomatic for the duration of infection. The serial interval was 3.24 days, and 27.5% (95% confidence interval [CI], 15.7%-40.0%) of transmissions occurred presymptomatically. Limited transmission amounted to a maximum reproduction number of 1.15 (95% CI, .·37-2.·36). No community transmission has been detected since 15 April., Conclusions: Vietnam has controlled SARS-CoV-2 spread through the early introduction of mass communication, meticulous contact tracing with strict quarantine, and international travel restrictions. The value of these interventions is supported by the high proportion of asymptomatic and imported cases, and evidence for substantial presymptomatic transmission., (© The Author(s) 2020. Published by Oxford University Press for the Infectious Diseases Society of America.)

Background: International air travel plays an important role in the global spread of SARS-CoV-2, and tracing of close contacts is an integral part of the public health response to COVID-19. We aimed to assess the timeliness of contact tracing among airline passengers arriving in Vietnam on flights containing COVID-19 cases and investigated factors associated with timeliness of contact tracing., Methods: We included data from 2228 passengers on 22 incoming flights between 2 and 19 March 2020. Contact tracing duration was assessed separately for the time between the date of index case confirmation and date of contact tracing initiation (interval I), and the date of contact tracing initiation and completion (interval II). We used log-rank tests and multivariable Poisson regression models to identify factors associated with timeliness., Results: The median duration of interval I and interval II was one (IQR: 1-2) and 3 days (IQR: 2-5), respectively. The contact tracing duration was shorter for passengers from flights where the index case was identified through mandatory testing directly upon arrival (median = 4; IQR: 3-5) compared to flights with index case detection through self-presentation at health facilities after arrival (median = 7; IQR: 5-8) (p-value = 0.018). Cumulative hazards for successful tracing were higher for Vietnamese nationals compared to non-Vietnamese nationals (p < 0.001)., Conclusions: Contact tracing among flight passengers in the early stage of the COVID-19 epidemic in Vietnam was timely though delays occurred on high workload days. Mandatory SARS-CoV-2 testing at arrival may reduce contact tracing duration and should be considered as an integrated screening tool for flight passengers from high-risk areas when entering low-transmission settings with limited contact tracing capacity. We recommend a standardized risk-based contact tracing approach for flight passengers during the ongoing COVID-19 epidemic.

To assess the role of in-flight transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), we investigated a cluster of cases among passengers on a 10-hour commercial flight. Affected persons were passengers, crew, and their close contacts. We traced 217 passengers and crew to their final destinations and interviewed, tested, and quarantined them. Among the 16 persons in whom SARS-CoV-2 infection was detected, 12 (75%) were passengers seated in business class along with the only symptomatic person (attack rate 62%). Seating proximity was strongly associated with increased infection risk (risk ratio 7.3, 95% CI 1.2-46.2). We found no strong evidence supporting alternative transmission scenarios. In-flight transmission that probably originated from 1 symptomatic passenger caused a large cluster of cases during a long flight. Guidelines for preventing SARS-CoV-2 infection among air passengers should consider individual passengers' risk for infection, the number of passengers traveling, and flight duration. [ABSTRACT FROM AUTHOR]

• Slowing the spread of COVID-19 was initially achieved in Vietnam. • Vietnam's healthcare system put the precaution of COVID-19 to priority. • Intensive and expansive contact, overall isolation, and sterilization should be implemented as soon as possible. • Further measures are expected in light of different progressive scenarios of the disease. Vietnam was slowing the spread of COVID-19 to 200 cases by the end of March. From perspective of a relatively vulnerable healthcare systems, timely interventions were implemented to different stage of pandemic progress to limit the spread. The authors compiled literature on different public health measures in Vietnam in compared to the progression of COVID-19 from January to March 2020. Three stages of pandemic progression of COVID-19 were recorded in Vietnam. At 213 confirmed cases under treatment and isolation, a range of interventions were enforced including intensive and expansive contact, mass testing, isolation, and sterilization. Many were in place before any case were reported. Preparation were key for Vietnam's healthcare system in the ever-changing landscape of COVID-19 pandemic. [ABSTRACT FROM AUTHOR]