Timing of last COVID-19 vaccine dose and SARS-CoV-2 breakthrough infections in fully (boosted) vaccinated healthcare personnel

COVID-19 and influenza hospitalizations and the role of COVID-19 vaccination in the post-pandemic period: A cross-sectional study from Saudi Arabia

BACKGROUND

The simultaneous spread of COVID-19 and seasonal influenza is an evolving healthcare challenge. This study examines the clinical characteristics of influenza and COVID-19 patients in Saudi Arabia and evaluates the impact of COVID-19 vaccination on hospital and ICU admission risks.

METHODS

We conducted a cross-sectional study of 235 patients (113 with influenza and 122 with COVID-19) admitted between October 2023 and March 2024 to Saudi public hospitals. Data on demographic factors, comorbidities, vaccination status, and ICU admission were collected from medical records. Logistic regression models were used to investigate associations between COVID-19 vaccination and clinical outcomes, adjusting for potential confounders.

RESULTS

Among the patients, 48.1 % were male, and 51.1 % were aged over 60 years. Among them, 80.0 % had received at least one COVID-19 vaccine dose; 6.8 % had one dose, 25.5 % had two doses, 46.4 % had three doses, and 1.3 % had four doses. COVID-19 patients had higher rates of comorbidities but lower rates of ICU admissions than influenza patients (18.0 % versus 5.3 %) and (7.4 % versus 13.3 %), respectively. COVID-19 vaccination was associated with a higher likelihood of receiving the seasonal influenza shot (OR [95 % CI] = 4.43 [1.29, 15.26]) and a lower likelihood of COVID-19 hospital admission (OR [95 % CI] = 0.39 [0.19, 0.81]) and ICU admission (OR [95 % CI] = 0.31 [0.12, 0.80]).

CONCLUSION

COVID-19 vaccination was significantly associated with a reduced risk of COVID-19 hospital admission and ICU admission in the post-pandemic period. These findings emphasize the importance of vaccination in mitigating severe outcomes from COVID-19 and influenza infections.

Measuring influencing factors affecting mortality rates during the COVID-19 pandemic

BACKGROUND

The COVID-19 pandemic has revealed clear deficiencies in global public health policies and healthcare systems when confronted with the emergence of a novel and deadly infectious disease.

OBJECTIVES

With 4 years elapsed since the onset of the pandemic, ample data now exist to analyse the associations between the implementation of diverse public health policies, sociodemographic factors and COVID-19 mortality rates.

METHODS

This study utilised the dataset compiled by 'Our World in Data' spanning the period of the COVID-19 pandemic from 2020 to 2022. Stochastic frontier analysis was employed to assess the influencing factors and their relationship with mortality rates resulting from COVID-19 infections across 156 countries or regions.

RESULTS

This study yielded several key findings: (1) There remains a 33% margin for improvement in the global mortality rate concerning the COVID-19 pandemic; (2) During the initial stage of the pandemic, when an effective vaccine was not yet available, implementing public health control policies could reduce both the infection and mortality rates; (3) Areas characterised by higher population densities, a greater proportion of individuals aged 65 and over, and elevated prevalence rates of diabetes demonstrated higher mortality rates; and (4) Increasing vaccination coverage emerged as an effective strategy for reducing mortality rates.

CONCLUSIONS

As our understanding of the COVID-19 virus improves, global economies and social interactions have gradually returned to normality. It is anticipated that the findings of this study can serve as a valuable reference in combating potential future pandemics caused by unknown viruses.

Adolescents With Breakthrough COVID-19 Infections Requiring Hospitalization: A Multicenter Retrospective Study

Background Vaccines have the most important role in the battle against the COVID-19 pandemic. With the widespread use of vaccines, COVID-19 has remarkably declined. Adolescents were vaccinated after approvals for this age group, which was later than adults, and a nationwide vaccination program was implemented in August 2021 in Turkey for adolescents ≥12 years of age. Therefore, we aimed to determine the effects of the COVID-19 nationwide adolescent vaccination program on adolescent hospitalizations due to COVID-19 and multisystem inflammatory syndrome in children (MIS-C) by comparing two periods, including the vaccination period (VP) and the pre-VP (PVP). The second aim of this study is to compare the clinical features and disease severity of vaccine-breakthrough COVID-19 hospitalizations with unvaccinated individuals in the VP. Methods A retrospective multicenter study was conducted to determine and compare the number of hospitalizations due to COVID-19 and MIS-C between the VP (September 1, 2021, to August 31, 2022) and PVP (September 1, 2020, to August 31, 2021). We also compared the characteristics, risk factors, and outcomes of breakthrough infections of adolescents aged 12-18, which required hospitalization with the same age group of unvaccinated hospitalized individuals during the VP. Results During the study period, 3967 children (0-18 years) were hospitalized in the PVP and 5143 (0-18 years) in the VP. Of them, 35.4% were adolescents (12-18 years) in the PVP, and this rate was 18.6% in the VP; relative risk was 0.6467 (95% confidence interval [CI]: 0.6058-0.6904; p < 0.001). Patients with breakthrough COVID-19 were older (201 vs. 175 months, p < 0.001) and less commonly hospitalized for COVID-19 (81.5% vs. 60.4%, p < 0.001, odds ratio [OR]: 0.347 [95% CI: 0.184-0.654]). The majority of these infections were asymptomatic and mild (32% vs.72.9%: p < 0.001, OR: 5.718 [95% CI: 2.920-11.200]), and PICU admission was less frequently required (p = 0.011, OR: 0.188 [95% CI: 0.045-0.793]). Most breakthrough COVID-19 infections occurred within three months after the last vaccine dose (54.2%). Conclusions This study demonstrated a significant decrease in adolescent hospitalizations due to COVID-19 and MIS-C after implementing COVID-19 vaccines in Turkey. Breakthrough cases were less severe and mostly occurred three months after the last dose. This study emphasizes the importance of COVID-19 vaccines and that parents' decisions may be changed, particularly those who hesitate to or refuse vaccination.

Incidence and Determinants of Symptomatic and Asymptomatic SARS-CoV-2 Breakthrough Infections After Booster Dose in a Large European Multicentric Cohort of Health Workers-ORCHESTRA Project

BACKGROUND

SARS-CoV-2 breakthrough infections (BI) after vaccine booster dose are a relevant public health issue.

METHODS

Multicentric longitudinal cohort study within the ORCHESTRA project, involving 63,516 health workers (HW) from 14 European settings. The study investigated the cumulative incidence of SARS-CoV-2 BI after booster dose and its correlation with age, sex, job title, previous infection, and time since third dose.

RESULTS

13,093 (20.6%) BI were observed. The cumulative incidence of BI was higher in women and in HW aged < 50 years, but nearly halved after 60 years. Nurses experienced the highest BI incidence, and administrative staff experienced the lowest. The BI incidence was higher in immunosuppressed HW (28.6%) vs others (24.9%). When controlling for gender, age, job title and infection before booster, heterologous vaccination reduced BI incidence with respect to the BNT162b2 mRNA vaccine [Odds Ratio (OR) 0.69, 95% CI 0.63-0.76]. Previous infection protected against asymptomatic infection [Relative Risk Ratio (RRR) of recent infection vs no infection 0.53, 95% CI 0.23-1.20] and even more against symptomatic infections [RRR 0.11, 95% CI 0.05-0.25]. Symptomatic infections increased from 70.5% in HW receiving the booster dose since < 64 days to 86.2% when time elapsed was > 130 days.

CONCLUSIONS

The risk of BI after booster is significantly reduced by previous infection, heterologous vaccination, and older ages. Immunosuppression is relevant for increased BI incidence. Time elapsed from booster affects BI severity, confirming the public health usefulness of booster. Further research should focus on BI trend after 4th dose and its relationship with time variables across the epidemics.

Measuring efficiency of the global fight against the COVID-19 pandemic

Objectives

The ongoing COVID-19 pandemic has led to an unprecedented loss of life and a severe economic downturn across the globe. Countries have adopted various social distancing and vaccination policies to reduce the spread of the disease and lessen the impact on healthcare systems. The world should work together to confront the disaster and challenge of COVID-19.

Methods

This study uses stochastic frontier analysis to measure the efficiency and influencing factors of the global response to COVID-19 epidemics and to provide follow-up strategies and reference guidelines.

Results

The results of this study show that (1) the average efficiency of the global response to COVID-19 is not good, with significant space for improvement of up to 60%; (2) adequate medical supplies and equipment can reduce mortality; (3) the initial implementation of social distancing policies and wearing masks can effectively reduce the infection rate; and (4) as infection rates and vaccination rates increase so that most people have basic immunity to COVID-19, the epidemic will gradually be reduced.

Conclusions

As the world becomes more aware of the COVID-19 disease, humans will gradually return to normal social interaction and lifestyles. The results of this study are expected to provide a reference for the future direction of the global fight against epidemics and the improvement of public health policies.