Infection control, occupational and public health measures including mRNA-based vaccination against SARS-CoV-2 infections to protect healthcare workers from variants of concern: A 14-month observational study using surveillance data

COVID-19 vaccines are effective at preventing symptomatic and severe infection among healthcare workers: A clinical review

Introduction

Health care workers (HCWs) have been at increased risk of infection during the SARS-CoV-2 pandemic and as essential workers have been prioritised for vaccination. Due to increased exposure HCW are considered a predictor of what might happen in the general population, particularly working age adults. This study aims to summarise effect of vaccination in this 'at risk' cohort.

Methods

Ovid MEDLINE and Embase were searched, and 358 individual articles were identified. Of these 49 met the inclusion criteria for review and 14 were included in a meta-analysis.

Results

Participants included were predominantly female and working age. Median time to infection was 51 days. Reported vaccine effectiveness against infection, symptomatic infection, and infection requiring hospitalisation were between 5 and 100 %, 34 and 100 %, and 65 and 100 % (respectively). No vaccinated HCW deaths were recorded in any study. Pooled estimates of protection against infection, symptomatic infection, and hospitalisation were, respectively, 84.7 % (95 % CI 72.6-91.5 %, p < 0.0001), 86.0 % (95 % CI 67.2 %-94.0 %; p < 0.0001), and 96.1 % (95 % CI 90.4 %-98.4 %). Waning protection against infection was reported by four studies, although protection against hospitalisation for severe infection persists for at least 6 months post vaccination.

Conclusions

Vaccination against SARS-CoV2 in HCWs is protective against infection, symptomatic infection, and hospitalisation. Waning protection is reported but this awaits more mature studies to understand durability more clearly. This study is limited by varying non-pharmacological responses to COVID-19 between included studies, a predominantly female and working age population, and limited information on asymptomatic transmission or long COVID protection.

Healthcare workers' compliance with COVID-19 prevention and control measures at De Martino Hospital, Mogadishu, Somalia: a cross-sectional study

BACKGROUND

Healthcare workers are a high-risk group for COVID-19 and protecting them is crucial for healthcare delivery. Limited studies have explored compliance with infection prevention and control (IPC) practices among Somali healthcare workers. This study aimed to determine compliance with IPC practices among healthcare workers in De Martino Public Hospital, Somalia.

METHODS

A cross-sectional study was conducted at the De Martino Public Hospital, Mogadishu, Somalia from August to October 2022, with the participation of 204 healthcare workers (response rate = 97%). Compliance was assessed using responses to 25 questions on a five-point Likert-type scale, and a median score of 20 was used to dichotomize compliance scores. A chi-square test and logistic regression analysis were performed to check the associations between healthcare workers' socio-demographic information, IPC-related factors, work conditions and practices on COVID-19, and IPC compliance during healthcare interventions using SPSS 23 version.

RESULTS

In total, 58.3% of the participants had good compliance with IPC. There were significant associations between IPC compliance and the type of healthcare worker (doctors and doctor assistants: 72.3%, nurses and paramedical staff: 67.3%, non-clinical staff: 5.7%, p < 0.01). After adjusting for potential confounding factors, compared to non-clinical staff, doctors and doctor assistants (OR: 12.11, 95% CI: 2.23-65.84) and nurses and paramedical staff (OR: 21.38, 95% CI: 4.23-108.01) had higher compliance with IPC measures. There were no significant associations between compliance and sex, marital status, vaccination status, or smoking (p > 0.05 for all).

CONCLUSIONS

Low levels of compliance with COVID-19 IPC measures were observed among hospital workers. Prioritizing awareness campaigns and behavior change interventions, especially among non-clinical staff, is crucial for effective COVID-19 infection prevention and control within hospitals.

Did the health care vaccine mandate work? An evaluation of the impact of the COVID-19 vaccine mandate on vaccine uptake and infection risk in a large cohort of Canadian health care workers

BACKGROUND

We aimed to evaluate the impact of health care vaccine mandates on vaccine uptake and infection risk in a cohort of Canadian health care workers (HCWs).

METHODS

We conduct interrupted time series analysis through a regression discontinuity in time approach to estimate the immediate and delayed impact of the mandate. Multilevel mixed effect modeling fitted with restricted maximum likelihood was used to estimate impact on infection risk.

RESULTS

The immediate and sustained effects of the mandate was a 0.19% (P < .05) and a 0.012% (P < .05) increase in the daily proportion of unvaccinated HCWs getting their first dose, respectively. An additional 623 (95% confidence interval: 613-667) HCWs received first doses compared to the predicted uptake absent the mandate. Adjusted test positivity declined by 0.053% (95% confidence interval: 0.035%, 0.069) for every additional day the mandate was in effect.

DISCUSSION

Our results indicate that the mandate was associated with significant increases in vaccine uptake and infection risk reduction in the cohort.

CONCLUSIONS

Given the benefit that vaccination could bring to HCWs, understanding strategies to enhance uptake is crucial for bolstering health system resilience, but steps must be taken to avert approaches that sacrifice trust, foster animosity, or exacerbate staffing constraints for short-term results.

Bacteria-surface interactions: role of impacting bacteria-laden droplets

Understanding the interactions of pathogenic droplets with surfaces is crucial to biomedical applications. In this study, using E. coli as the model microbe, we investigate the impact of a bacteria-laden droplet on different substrates, both bare and antimicrobial. In doing so, we unveil the significance of kinetic energy and spreading parameters of the impacting droplet in determining the microbes' proliferation capabilities. Our results indicate an inverse relationship between the impact Weber number and the bacterial ability to proliferate. We reveal that the mechanical stress generated during impact impedes the capabilities of microbes present inside the droplet to create their progeny. Following an order analysis of the mechanical stress generated, we argue that the impact does not induce lysis-driven cell death of the bacteria; rather, it promotes a stress-driven transition of viable bacteria to a viable-but-non-culturable (VBNC) state. Furthermore, variations in the concentration of particles on the antimicrobial surfaces revealed the role of the post-impact spreading behaviour in dictating bacterial proliferation capabilities. Contrary to the conventional notion, we demonstrate that during the early stages of interaction, a bare substrate may outperform an antibacterial substrate in the inactivation of the bacterial load. Finally, we present an interaction map illustrating the complex relationship between bacterial colony-forming units, bactericide concentration on the surface, and the impact Weber number. We believe that the inferences of the study, highlighting the effect of mechanical stresses on the soft cell wall of microbes, could be a useful design consideration for the development of antimicrobial surfaces.

Are COVID-19 vaccination mandates for healthcare workers effective? A systematic review of the impact of mandates on increasing vaccination, alleviating staff shortages and decreasing staff illness

INTRODUCTION

The rapid development of COVID-19 vaccines is a cornerstone in the global effort to combat the pandemic. Healthcare workers (HCWs), being at the forefront of the pandemic response, have been the focus of vaccine mandate policies. This review aims to evaluate the impacts of COVID-19 vaccine mandates among HCWs, a critical step in understanding the broader implications of such policies in healthcare settings.

OBJECTIVE

The review seeks to synthesize available literature to contribute to greater understanding of the outcomes associated with COVID-19 vaccine mandates for HCWs including vaccine uptake, infection rates, and staffing.

METHODS

A systematic search of relevant literature published from March 2020 to September 2023 was conducted. The Newcastle-Ottawa scale was employed for quality assessment of the included articles. A total of 4,779 publications were identified, with 15 studies meeting the inclusion criteria for the review. A narrative synthesis approach was used to analyze these studies.

RESULTS

COVID-19 vaccine mandates for HCWs were broadly successful in increasing vaccine uptake in most settings. Although the penalties imposed on unvaccinated HCWs did not lead to major disruption of health services, less well-resourced areas may have been more impacted. Furthermore, there is insufficient literature on the impact of the vaccine mandate on reducing SARS-CoV-2 infection among HCWs.

CONCLUSION

COVID-19 vaccine mandates for HCWs have significant implications for public health policy and healthcare management. The findings underscore the need for tailored approaches in mandate policies, considering the specific contexts of healthcare settings and the diverse populations of HCWs. While mandates have shown potential in increasing vaccine uptake with minimal impacts to staffing, more work is needed to investigate the impacts of mandates across various contexts. In addition to these impacts, future research should focus on long-term effects and implications on broader public health strategies.

Systematizing Information Use to Address Determinants of Health Worker Health in South Africa: A Cross-sectional Mixed Method Study

Background

Recognizing that access to safe and healthy working conditions is a human right, the World Health Organization (WHO) calls for specific occupational safety and health (OSH) programs for health workers (HWs). The WHO health systems' building blocks, and the International Labour Organization (ILO), highlight the importance of information as part of effective systems. This study examined how OSH stakeholders access, use, and value an occupational health information system (OHIS).

Methods

A cross-sectional survey of OSH stakeholders was conducted as part of a larger quasi experimental study in four teaching hospitals. The study hospitals and participants were purposefully selected and data collected using a modified questionnaire with both closed and open-ended questions. Quantitative analysis was conducted and themes identified for qualitative analysis. Ethics approval was provided by the University of Pretoria and University of British Columbia.

Results

There were 71 participants comprised of hospital managers, health and safety representatives, trade unions representatives and OSH professionals. At least 42% reported poor accessibility and poor timeliness of OHIS for decision-making. Only 50% had access to computers and 27% reported poor computer skills. When existing, OHIS was poorly organized and needed upgrades, with 85% reporting the need for significant reforms. Only 45% reported use of OHIS for decision-making in their OSH role.

Conclusion

Given the gap in access and utilization of information needed to protect worker's rights to a safe and healthy workplace, more attention is warranted to OHIS development and use as well as education and training in South Africa and beyond.

Vaccine efficacy against SARS-CoV-2 for Pfizer BioNTech, Moderna, and AstraZeneca vaccines: a systematic review

The purpose of this systematic review was to report on the vaccine efficacy (VE) of three SARS-CoV-2 vaccines approved by Health Canada: Pfizer BioNTech, Moderna, and AstraZeneca. Four databases were searched for primary publications on population-level VE. Ninety-two publications matched the inclusion criteria, and the extracted data were separated by vaccine type: mRNA vaccines (Pfizer and Moderna) and the AstraZeneca vaccine. The median VE for PCR-positive patients and various levels of clinical disease was determined for the first and second doses of both vaccine types against multiple SARS-CoV-2 variants. The median VE for PCR-positive infections against unidentified variants from an mRNA vaccine was 64.5 and 89%, respectively, after one or two doses. The median VE for PCR-positive infections against unidentified variants from the AstraZeneca vaccine was 53.4 and 69.6%, respectively, after one or two doses. The median VE for two doses of mRNA for asymptomatic, symptomatic, and severe infection against unidentified variants was 85.5, 93.2, and 92.2%, respectively. The median VE for two doses of AstraZeneca for asymptomatic, symptomatic, and severe infection against unidentified variants was 69.7, 71, and 90.2%, respectively. Vaccine efficacy numerically increased from the first to the second dose, increased from the first 2 weeks to the second 2 weeks post-vaccination for both doses, but decreased after 4 months from the second dose. Vaccine efficacy did not differ by person's age.

Comparison of infection severity of vaccinated and unvaccinated health workers with Corona Virus: A cohort study

BACKGROUND

Hospital staff members are most susceptible to the COVID-19 illness, which is currently prevented through vaccination. Hospital staff members also refuse vaccinations, albeit the underlying causes have not been identified. The study aimed to compare the severity of the symptoms of the disease on the body for health workers who took the coronavirus vaccine and those who did not take the vaccine.

MATERIALS AND METHODS

This cohort study aimed to estimate the of infection severity of vaccinated and unvaccinated health workers with Corona Virus in Mosul Hospital, Iraq. Data were obtained from the General Mosul Hospital, Nineveh, Iraq. The first of the three components of this questionnaire outlined the demographic characteristics. Second part: First group of unvaccinated Health care workers included those who had not received the COVID-19 immunization or had only gotten one dose of the vaccine; the second group included those who had received their first dose of Corona vaccine and the third group included those who had received two doses of Corona Vaccine. HCWs who got corona vaccine were included in the three-dose final group.

RESULTS

The study's findings indicate that as compared to the corona vaccination, the vaccinated experienced less severe infection symptoms and fewer dosage stays. The high share of healthcare workers among the 20- to 30-year-olds who received vaccinations accounts for the gender gap between the vaccinated and unvaccinated groups.

CONCLUSION

This study concluded that the results of the corona vaccine are not consistent among the various groups of HCWs. The acceptability of vaccinations is practically unanimous among nurses, but less so among doctors and other healthcare professionals.

Vaccination, time lost from work, and COVID-19 infections: a Canadian healthcare worker retrospective cohort study

The COVID-19 pandemic highlighted hurdles for healthcare delivery and personnel globally. Vaccination has been an important tool for preventing severe illness and death in healthcare workers (HCWs) as well as the public at large. However, vaccination has resulted in some HCWs requiring time off work post-vaccination to recover from adverse events. We aimed to understand which HCWs needed to take time off work post-vaccination, for which vaccine types and sequence, and how post-vaccination absence impacted uptake of booster doses in a cohort of 26,267 Canadian HCWs. By March 31, 2022, more than 98% had received at least two doses of the approved COVID-19 vaccines, following a two-dose mandate. We found that recent vaccination and longer intervals between doses were associated with significantly higher odds of time-loss, whereas being a medical resident and receiving the BNT162b2 vaccine were associated with lower odds. A history of lab-confirmed SARS-CoV-2 infection was associated with lower odds of receiving a booster dose compared with no documented infection, aOR 0.61 (95% CI: 0.55, 0.68). Similarly, taking sick time following the first or second dose was associated with lower odds of receiving a booster dose, aOR 0.83 (95% CI: 0.75, 0.90). As SARS-CoV-2 becomes endemic, the number and timing of additional doses for HCWs requires consideration of prevention of illness as well as service disruption from post-vaccination time-loss. Care should be taken to ensure adequate staffing if many HCWs are being vaccinated, especially for coverage for those who are more likely to need time off to recover.

Risk and protective factors for severe acute respiratory coronavirus virus 2 (SARS-CoV-2) infection among healthcare workers: A test-negative case-control study in Québec, Canada

OBJECTIVES

In Québec, Canada, we evaluated the risk of severe acute respiratory coronavirus virus 2 (SARS-CoV-2) infection associated with (1) the demographic and employment characteristics among healthcare workers (HCWs) and (2) the workplace and household exposures and the infection prevention and control (IPC) measures among patient-facing HCWs.

DESIGN

Test-negative case-control study.

SETTING

Provincial health system.

PARTICIPANTS

HCWs with PCR-confirmed coronavirus disease 2019 (COVID-19) diagnosed between November 15, 2020, and May 29, 2021 (ie, cases), were compared to HCWs with compatible symptoms who tested negative during the same period (ie, controls).

METHODS

Adjusted odds ratios (aORs) of infection were estimated using regression logistic models evaluating demographic and employment characteristics (all 4,919 cases and 4,803 controls) or household and workplace exposures and IPC measures (2,046 patient-facing cases and 1,362 controls).

RESULTS

COVID-19 risk was associated with working as housekeeping staff (aOR, 3.6), as a patient-support assistant (aOR, 1.9), and as nursing staff (aOR, 1.4), compared to administrative staff. Other risk factors included being unexperienced (aOR, 1.5) and working in private seniors' homes (aOR, 2.1) or long-term care facilities (aOR, 1.5), compared to acute-care hospitals. Among patient-facing HCWs, exposure to a household contact was reported by 9% of cases and was associated with the highest risk of infection (aOR, 7.8). Most infections were likely attributable to more frequent exposure to infected patients (aOR, 2.7) and coworkers (aOR, 2.2). Wearing an N95 respirator during contacts with COVID-19 patients (aOR, 0.7) and vaccination (aOR, 0.2) were the measures associated with risk reduction.

CONCLUSION

In the context of the everchanging SARS-CoV-2 virus with increasing transmissibility, measures to ensure HCW protection, including vaccination and respiratory protection, and patient safety will require ongoing evaluation.

Urban-rural divide in COVID-19 infection and vaccination rates in healthcare workers in British Columbia, Canada

Introduction

Healthcare workers (HCWs) play a critical role in responding to the COVID-19 pandemic. Early in the pandemic, urban centres were hit hardest globally; rural areas gradually became more impacted. We compared COVID-19 infection and vaccine uptake in HCWs living in urban versus rural locations within, and between, two health regions in British Columbia (BC), Canada. We also analysed the impact of a vaccine mandate for HCWs.

Methods

We tracked laboratory-confirmed SARS-CoV-2 infections, positivity rates and vaccine uptake in all 29,021 HCWs in Interior Health (IH) and all 24,634 HCWs in Vancouver Coastal Health (VCH), by occupation, age and home location, comparing to the general population in that region. We then evaluated the impact of infection rates as well as the mandate on vaccination uptake.

Results

While we found an association between vaccine uptake by HCWs and HCW COVID-19 rates in the preceding 2-week period, the higher rates of COVID-19 infection in some occupational groups did not lead to increased vaccination in these groups. By 27 October 2021, the date that unvaccinated HCWs were prohibited from providing healthcare, only 1.6% in VCH compared with 6.5% in IH remained unvaccinated. Rural workers in both areas had significantly higher unvaccinated rates compared with urban dwellers. Over 1800 workers, comprising 6.7% of rural HCWs and 3.6% of urban HCWs, remained unvaccinated and set to be terminated from their employment. While the mandate prompted a significant increase in uptake of second doses, the impact on the unvaccinated was less clear.

Conclusions

As rural areas often suffer from under-staffing, loss of HCWs could have serious impacts on healthcare provision as well as on the livelihoods of unvaccinated HCWs. Greater efforts are needed to understand how to better address the drivers of rural-related vaccine hesitancy.

Protecting healthcare workers during a pandemic: what can a WHO collaborating centre research partnership contribute?

Objectives

To ascertain whether and how working as a partnership of two World Health Organization collaborating centres (WHOCCs), based respectively in the Global North and Global South, can add insights on "what works to protect healthcare workers (HCWs) during a pandemic, in what contexts, using what mechanism, to achieve what outcome".

Methods

A realist synthesis of seven projects in this research program was carried out to characterize context (C) (including researcher positionality), mechanism (M) (including service relationships) and outcome (O) in each project. An assessment was then conducted of the role of the WHOCC partnership in each study and overall.

Results

The research found that lower-resourced countries with higher economic disparity, including South Africa, incurred greater occupational health risk and had less acceptable measures to protect HCWs at the onset of the COVID-19 pandemic than higher-income more-equal counterpart countries. It showed that rigorously adopting occupational health measures can indeed protect the healthcare workforce; training and preventive initiatives can reduce workplace stress; information systems are valued; and HCWs most at-risk (including care aides in the Canadian setting) can be readily identified to trigger adoption of protective actions. The C-M-O analysis showed that various ways of working through a WHOCC partnership not only enabled knowledge sharing, but allowed for triangulating results and, ultimately, initiatives for worker protection.

Conclusions

The value of an international partnership on a North-South axis especially lies in providing contextualized global evidence regarding protecting HCWs as a pandemic emerges, particularly with bi-directional cross-jurisdiction participation by researchers working with practitioners.

Estimating COVID-19 Vaccination and Booster Effectiveness Using Electronic Health Records From an Academic Medical Center in Michigan

Introduction

Observational studies of COVID-19 vaccines' effectiveness can provide crucial information regarding the strength and durability of protection against SARS-CoV-2 infection and whether the protective response varies across different patient subpopulations and in the context of different SARS-CoV-2 variants.

Methods

We used a test-negative study design to assess vaccine effectiveness against SARS-CoV-2 infection and severe COVID-19 resulting in hospitalization, intensive care unit admission, or death using electronic health records data of 170,741 adults who had been tested for COVID-19 at the University of Michigan Medical Center between January 1 and December 31, 2021. We estimated vaccine effectiveness by comparing the odds of vaccination between cases and controls during each 2021 calendar quarter and stratified all outcomes by vaccine type, patient demographic and clinical characteristics, and booster status.

Results

Unvaccinated individuals had more than double the rate of infections (12.1% vs 4.7%) and >3 times the rate of severe COVID-19 outcomes (1.4% vs 0.4%) than vaccinated individuals. COVID-19 vaccines were 62.1% (95% CI=60.3, 63.8) effective against a new infection, with protection waning in the last 2 quarters of 2021. The vaccine effectiveness against severe disease overall was 73.7% (95% CI=69.6, 77.3) and remained high throughout 2021. Data from the last quarter of 2021 indicated that adding a booster dose augmented effectiveness against infection up to 87.3% (95% CI=85.0, 89.2) and against severe outcomes up to 94.0% (95% CI=89.5, 96.6). Pfizer-BioNTech and Moderna vaccines showed comparable performance when controlling for vaccination timing. Vaccine effectiveness was greater in more socioeconomically affluent areas and among healthcare workers; otherwise, we did not detect any significant modification of vaccine effectiveness by covariates, including gender, race, and SES.

Conclusions

COVID-19 vaccines were highly protective against infection and severe COVID-19 resulting in hospitalization, intensive care unit admission, or death. Administration of a booster dose significantly increased vaccine effectiveness against both outcomes. Ongoing surveillance is required to assess the durability of these findings.

A Mixed-Methods Study of Risk Factors and Experiences of Health Care Workers Tested for the Novel Coronavirus in Canada

A reappraisal of mitigation strategies against occupational hazards is required to ensure that all health workers – not just those in perceived “high-risk” work environments - are protected. This will mean reducing community-level risks and ensuring that the same level of IPC measures, PPE training and supply is available when needed.

The aims of this study were to investigate occupational and non–work-related risk factors of coronavirus disease 2019 among health care workers (HCWs) in Vancouver Coastal Health, British Columbia, Canada, and to examine how HCWs described their experiences.

SARS-CoV-2: phenotype, genotype, and characterization of different variants

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the cause of coronavirus disease 2019 (COVID-19), a major international public health concern. Because of very similar amino acid sequences of the seven domain names, SARS-CoV-2 belongs to the Coronavirinae subfamily of the family Coronaviridae, order Nidovirales, and realm Riboviria, placed in exceptional clusters, but categorized as a SARS-like species. As the RNA virus family with the longest genome, the Coronaviridae genome consists of a single strand of positive RNA (25-32 kb in length). Four major structural proteins of this genome include the spike (S), membrane (M), envelope (E), and the nucleocapsid (N) protein, all of which are encoded within the 3' end of the genome. By engaging with its receptor, angiotensin-converting enzyme 2 (ACE2), SARS-CoV-2 infects host cells. According to the most recent epidemiological data, as the illness spread globally, several genetic variations of SARS-CoV-2 appeared quickly, with the World Health Organization (WHO) naming 11 of them. Among these, seven SARS-CoV-2 subtypes have received the most attention. Alpha (B.1.1.7), Beta (B.1.351), Gamma (P.1), Delta (B.1.617.2), and Omicron (B.1.617.2) are now designated as variations of concern (VOC) (B.1.1.529). Lambda (C.37) and Mu are variations of interest (VOI) (B.1.621). The remaining six are either being monitored or are no longer considered a threat. On the basis of studies done so far, antiviral drugs, antibiotics, glucocorticoids, recombinant intravenous immunoglobulin, plasma therapy, and IFN-α2b have been used to treat patients. Moreover, full vaccination is associated with lower infection and helps prevent transmission, but the risk of infection cannot be eliminated completely in vaccinated people.

Dosing interval strategies for two-dose COVID-19 vaccination in 13 middle-income countries of Europe: Health impact modelling and benefit-risk analysis

Background

In settings where the COVID-19 vaccine supply is constrained, extending the intervals between the first and second doses of the COVID-19 vaccine may allow more people receive their first doses earlier. Our aim is to estimate the health impact of COVID-19 vaccination alongside benefit-risk assessment of different dosing intervals in 13 middle-income countries (MICs) of Europe.

Methods

We fitted a dynamic transmission model to country-level daily reported COVID-19 mortality in 13 MICs in Europe (Albania, Armenia, Azerbaijan, Belarus, Bosnia and Herzegovina, Bulgaria, Georgia, Republic of Moldova, Russian Federation, Serbia, North Macedonia, Turkey, and Ukraine). A vaccine product with characteristics similar to those of the Oxford/AstraZeneca COVID-19 (AZD1222) vaccine was used in the base case scenario and was complemented by sensitivity analyses around efficacies similar to other COVID-19 vaccines. Both fixed dosing intervals at 4, 8, 12, 16, and 20 weeks and dose-specific intervals that prioritise specific doses for certain age groups were tested. Optimal intervals minimise COVID-19 mortality between March 2021 and December 2022. We incorporated the emergence of variants of concern (VOCs) into the model and conducted a benefit-risk assessment to quantify the tradeoff between health benefits versus adverse events following immunisation.

Findings

In all countries modelled, optimal strategies are those that prioritise the first doses among older adults (60+ years) or adults (20+ years), which lead to dosing intervals longer than six months. In comparison, a four-week fixed dosing interval may incur 10.1% [range: 4.3% - 19.0%; n = 13 (countries)] more deaths. The rapid waning of the immunity induced by the first dose (i.e. with means ranging 60-120 days as opposed to 360 days in the base case) resulted in shorter optimal dosing intervals of 8-20 weeks. Benefit-risk ratios were the highest for fixed dosing intervals of 8-12 weeks.

Interpretation

We infer that longer dosing intervals of over six months could reduce COVID-19 mortality in MICs of Europe. Certain parameters, such as rapid waning of first-dose induced immunity and increased immune escape through the emergence of VOCs, could significantly shorten the optimal dosing intervals.

Funding

World Health Organization.

Impact of non-pharmaceutical interventions and vaccination on COVID-19 outbreaks in Nunavut, Canada: a Canadian Immunization Research Network (CIRN) study

Background

Nunavut, the northernmost Arctic territory of Canada, experienced three community outbreaks of the coronavirus disease 2019 (COVID-19) from early November 2020 to mid-June 2021. We sought to investigate how non-pharmaceutical interventions (NPIs) and vaccination affected the course of these outbreaks.

Methods

We used an agent-based model of disease transmission to simulate COVID-19 outbreaks in Nunavut. The model encapsulated demographics and household structure of the population, the effect of NPIs, and daily number of vaccine doses administered. We fitted the model to inferred, back-calculated infections from incidence data reported from October 2020 to June 2021. We then compared the fit of the scenario based on case count data with several counterfactual scenarios without the effect of NPIs, without vaccination, and with a hypothetical accelerated vaccination program whereby 98% of the vaccine supply was administered to eligible individuals.

Results

We found that, without a territory-wide lockdown during the first COVID-19 outbreak in November 2020, the peak of infections would have been 4.7 times higher with a total of 5,404 (95% CrI: 5,015—5,798) infections before the start of vaccination on January 6, 2021. Without effective NPIs, we estimated a total of 4,290 (95% CrI: 3,880—4,708) infections during the second outbreak under the pace of vaccination administered in Nunavut. In a hypothetical accelerated vaccine rollout, the total infections during the second Nunavut outbreak would have been 58% lower, to 1,812 (95% CrI: 1,593—2,039) infections. Vaccination was estimated to have the largest impact during the outbreak in April 2021, averting 15,196 (95% CrI: 14,798—15,591) infections if the disease had spread through Nunavut communities. Accelerated vaccination would have further reduced the total infections to 243 (95% CrI: 222—265) even in the absence of NPIs.

Conclusions

NPIs have been essential in mitigating pandemic outbreaks in this large, geographically distanced and remote territory. While vaccination has the greatest impact to prevent infection and severe outcomes, public health implementation of NPIs play an essential role in the short term before attaining high levels of immunity in the population.

Supplementary information

The online version contains supplementary material available at 10.1186/s12889-022-13432-1.

SARS-CoV-2 mRNA vaccine effectiveness in healthcare workers by dosing interval and time since vaccination: test negative design, British Columbia, Canada

Background

One- and two-dose mRNA vaccine effectiveness (VE) estimates against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection by dosing interval and time since vaccination were assessed among healthcare workers (HCWs) in publicly funded acute and community (nonresidential) healthcare facilities in British Columbia, Canada.

Methods

A test-negative design was used with controls matched to cases (6:1) on epidemiological week of SARS-CoV-2 test date. mRNA vaccination was defined by receipt of the first dose ≥21 days or second dose ≥14 days before the test date. HCWs ≥18 years old tested for SARS-CoV-2 between epi-weeks 3 and 39 (January 17–October 2, 2021) were included, when varying dosing intervals and a mix of circulating variants of concern contributed, including Delta dominance provincially from epi-week 31 (August 1).

Results

Single- and two-dose analyses included 1265 and 1246 cases, respectively. The median follow-up period (interquartile range) was 49 (34–69) days for single-dose and 89 (61–123) days for two-dose recipients, with 12%, 31%, and 58% of second doses given 3–5, 6, or ≥7 weeks after the first. Adjusted mRNA VE against SARS-CoV-2 was 71% (95% CI, 66%–76%) for one dose and 90% (95% CI, 88%–92%) for two doses, similar to two heterologous mRNA doses (92%; 95% CI, 86%–95%). Two-dose VE remained >80% at ≥28 weeks post–second dose. Two-dose VE was consistently 5%–7% higher with a ≥7-week vs 3–5-week interval between doses, but with overlapping confidence intervals.

Conclusions

Among HCWs, we report substantial single-dose and strong and sustained two-dose mRNA vaccine protection, with the latter maintained for at least 7 months. These findings support a longer interval between doses, with global health and equity implications.

Effectiveness of the Ad26.COV2.S vaccine in health-care workers in South Africa (the Sisonke study): results from a single-arm, open-label, phase 3B, implementation study

BACKGROUND

We aimed to assess the effectiveness of a single dose of the Ad26.COV2.S vaccine (Johnson & Johnson) in health-care workers in South Africa during two waves of the South African COVID-19 epidemic.

METHODS

In the single-arm, open-label, phase 3B implementation Sisonke study, health-care workers aged 18 years and older were invited for vaccination at one of 122 vaccination sites nationally. Participants received a single dose of 5 × 1010 viral particles of the Ad26.COV2.S vaccine. Vaccinated participants were linked with their person-level data from one of two national medical insurance schemes (scheme A and scheme B) and matched for COVID-19 risk with an unvaccinated member of the general population. The primary outcome was vaccine effectiveness against severe COVID-19, defined as COVID-19-related admission to hospital, hospitalisation requiring critical or intensive care, or death, in health-care workers compared with the general population, ascertained 28 days or more after vaccination or matching, up to data cutoff. This study is registered with the South African National Clinical Trial Registry, DOH-27-022021-6844, ClinicalTrials.gov, NCT04838795, and the Pan African Clinical Trials Registry, PACTR202102855526180, and is closed to accrual.

FINDINGS

Between Feb 17 and May 17, 2021, 477 102 health-care workers were enrolled and vaccinated, of whom 357 401 (74·9%) were female and 119 701 (25·1%) were male, with a median age of 42·0 years (33·0-51·0). 215 813 vaccinated individuals were matched with 215 813 unvaccinated individuals. As of data cutoff (July 17, 2021), vaccine effectiveness derived from the total matched cohort was 83% (95% CI 75-89) to prevent COVID-19-related deaths, 75% (69-82) to prevent COVID-19-related hospital admissions requiring critical or intensive care, and 67% (62-71) to prevent COVID-19-related hospitalisations. The vaccine effectiveness for all three outcomes were consistent across scheme A and scheme B. The vaccine effectiveness was maintained in older health-care workers and those with comorbidities including HIV infection. During the course of the study, the beta (B.1.351) and then the delta (B.1.617.2) SARS-CoV-2 variants of concerns were dominant, and vaccine effectiveness remained consistent (for scheme A plus B vaccine effectiveness against COVID-19-related hospital admission during beta wave was 62% [95% CI 42-76] and during delta wave was 67% [62-71], and vaccine effectiveness against COVID-19-related death during beta wave was 86% [57-100] and during delta wave was 82% [74-89]).

INTERPRETATION

The single-dose Ad26.COV2.S vaccine shows effectiveness against severe COVID-19 disease and COVID-19-related death after vaccination, and against both beta and delta variants, providing real-world evidence for its use globally.

FUNDING

National Treasury of South Africa, the National Department of Health, Solidarity Response Fund NPC, The Michael & Susan Dell Foundation, The Elma Vaccines and Immunization Foundation, and the Bill & Melinda Gates Foundation.

Severe Acute Respiratory Syndrome Coronavirus-2 seroprevalence in South-Central Uganda, during 2019-2021

BACKGROUND

Globally, key subpopulations such as healthcare workers (HCW) may have a higher risk of contracting SARS-CoV-2. In Uganda, limited access to Personal Protective Equipment and lack of clarity on the extent/pattern of community spread may exacerbate this situation. The country established infection prevention/control measures such as lockdowns and proper hand hygiene. However, due to resource limitations and fatigue, compliance is low, posing continued onward transmission risk. This study aimed to describe extent of SARS-CoV-2 seroprevalence in selected populations within the Rakai region of Uganda.

METHODS

From 30th November 2020 to 8th January 2021, we collected venous blood from 753 HCW at twenty-six health facilities in South-Central Uganda and from 227 population-cohort participants who reported specific COVID-19 like symptoms (fever, cough, loss of taste and appetite) in a prior phone-based survey conducted (between May and August 2020) during the first national lockdown. 636 plasma specimens collected from individuals considered high risk for SARS-CoV-2 infection, prior to the first confirmed COVID-19 case in Uganda were also retrieved. Specimens were tested for antibodies to SARS-CoV-2 using the CoronaChek™ rapid COVID-19 IgM/IgG lateral flow test assay. IgM only positive samples were confirmed using a chemiluminescent microparticle immunoassay (CMIA) (Architect AdviseDx SARS-CoV-2 IgM) which targets the spike protein. SARS-CoV-2 exposure was defined as either confirmed IgM, both IgM and IgG or sole IgG positivity. Overall seroprevalence in each participant group was estimated, adjusting for test performance.

RESULTS

The seroprevalence of antibodies to SARS-CoV-2 in HCW was 26.7% [95%CI: 23.5, 29.8] with no difference by sex, age, or cadre. We observed no association between PPE use and seropositivity among exposed healthcare workers. Of the phone-based survey participants, 15.6% [95%CI: 10.9, 20.3] had antibodies to SARS-CoV-2, with no difference by HIV status, sex, age, or occupation. Among 636 plasma specimens collected prior to the first confirmed COVID-19 case, 2.3% [95%CI: 1.2, 3.5] were reactive.

CONCLUSIONS

Findings suggest high seroprevalence of antibodies to SARS-CoV-2 among HCW and substantial exposure in persons presenting with specific COVID-19 like symptoms in the general population of South-Central Uganda. Based on current limitations in serological test confirmation, it remains unclear whether seroprevalence among plasma specimens collected prior to confirmation of the first COVID-19 case implies prior SARS-CoV-2 exposure in Uganda.

Modified mRNA-Based Vaccines Against Coronavirus Disease 2019

The pandemic of coronavirus disease 2019 (COVID-19) continuously causes deaths worldwide, representing a considerable challenge to health care and economic systems with a new precedent in human history. Many therapeutic medicines primarily focused on preventing severe organ damage and complications, which can be fatal in some confirmed cases. The synthesized modified mRNA (modRNA) represents a nonviral, integration-free, zero-footprint, efficient, and safe strategy for vaccine discovery. modRNA-based technology has facilitated the rapid development of the first COVID-19 vaccines due to its cost- and time-saving properties, thus initiating a new era of prophylactic vaccines against infectious diseases. Recently, COVID-19 modRNA vaccines were approved, and a large-scale vaccination campaign began worldwide. To date, results suggest that the modRNA vaccines are highly effective against virus infection, which causes COVID-19. Although short-term studies have reported that their safety is acceptable, long-term safety and protective immunity remain unclear. In this review, we describe two major approved modRNA vaccines and discuss their potential myocarditis complications.

Psychological factors affecting COVID-19 vaccine acceptance in Indonesia

INTRODUCTION

Increasing the rate of vaccination is crucial in combating the COVID-19 pandemic. However, a survey of 112,888 Indonesians found that only 64.8% Indonesians were willing to be vaccinated, with 7.6% refusing all vaccines and 27.6% are unsure. Several factors were related to this vaccine hesitancy and refusal, such as cognitive reflection, trust in authoritative figures, and personality traits. This study aims to identify psychological determinants and other factors associated with vaccine hesitancy and vaccine refusal. This was a cross-sectional study with data collection done in March 2021 using a questionnaire. We collected demographic data, respondents' stance on vaccination, as well as their psychology measurement. IBM SPSS 26.0 (Statistical Package for the Social Sciences, IBM Corp., Armonk, NY, USA) was used for statistical analysis.

RESULTS

The data of 190 respondents were collected for this study. There are 165 respondents (86.8%) who belong to "vaccine acceptance", while 25 are "vaccine hesitance" or "vaccine resistance." Multivariate analysis shows that frequency of COVID-19 tests (p = 0.03), smoking status (p = 0.035), agreeableness trait (p = 0.001), trust in government (p = 0.04) and trust in scientist (p = 0.049) are significantly associated with the two population.

CONCLUSION

Several demographic and psychological factors affect the COVID-19 vaccine acceptance. The government and other related parties should consider these factors when adjusting for future policies controlling the COVID-19 pandemic and increasing the vaccination rate.

Physicians' Experience with COVID-19 Vaccination: A Survey Study

BACKGROUND

COVID-19 vaccine hesitancy remains high in the general population and is the main determinant of low vaccination rates and of the fourth pandemic wave severity in Romania. Additional information is needed to raise awareness over vaccine efficiency and the safety profile.

OBJECTIVE

To assess self-reported experience related to COVID-19 vaccination in Romanian physicians.

DESIGN, SETTING, AND PARTICIPANTS

A cross-sectional, self-administered questionnaire-based survey, distributed online in the period 24 March to 24 May 2021. The survey included 30 cascade questions with skip logic filters. All physicians included filled in the questionnaire voluntarily and anonymously. Not all respondents filled in all questions. Main outcome and measure: Primary outcomes addressed were related to the COVID-19 vaccine safety profile.

RESULTS

407/467 (87.15%) of the respondents' physicians were fully vaccinated, mostly with the Pfizer-BioNTech (Comirnaty)-BNT162b2 vaccine, with the peak of immunization in January 2021, with almost four-fifths of the study participants. Regarding COVID-19, almost 20% physicians had the infection and one declared COVID-19 re-infection. A number of 48/420 (11.42%) and 47/419 (11.22%) of the vaccinated physicians did not report any side effects after the first or second vaccine dose. However, most of the side effects reported were minor. Only 50/360 (13.88%) physicians reported the vaccine side effects on the dedicated online national platform. Approximately 40% respondents checked the anti-spike SARS-CoV2 antibodies' titer after complete vaccination, of which two cases reported indeterminate levels. Lower anti-spike SARS-CoV2 antibodies' titer of 100-1000 times the laboratory limit was more frequent in naive physicians (36.95% versus 14.28%, p = 0.012), moderate titers were similar, while very high levels, more than 10,000 times laboratory limit, were more frequent in physicians with previous COVID-19 infection (2.17% versus 42.85%, p < 0.001).

CONCLUSIONS AND RELEVANCE

In this cross-sectional survey study on the COVID-19 vaccination among Romanian physicians, we describe a safety vaccination profile among Romanian physicians.

Vaccine versus Variants (3Vs): Are the COVID-19 Vaccines Effective against the Variants? A Systematic Review

BACKGROUND

With the emergence and spread of new SARS-CoV-2 variants, concerns are raised about the effectiveness of the existing vaccines to protect against these new variants. Although many vaccines were found to be highly effective against the reference COVID-19 strain, the same level of protection may not be found against mutation strains. The objective of this study is to systematically review relevant studies in the literature and compare the efficacy of COVID-19 vaccines against new variants.

METHODS

We conducted a systematic review of research published in Scopus, PubMed, and Google Scholar until 30 August 2021. Studies including clinical trials, prospective cohorts, retrospective cohorts, and test negative case-controls that reported vaccine effectiveness against any COVID-19 variants were considered. PRISMA recommendations were adopted for screening, eligibility, and inclusion.

RESULTS

129 unique studies were reviewed by the search criteria, of which 35 met the inclusion criteria. These comprised of 13 test negative case-control studies, 6 Phase 1-3 clinical trials, and 16 observational studies. The study location, type, vaccines used, variants considered, and reported efficacies were highlighted.

CONCLUSION

Full vaccination (two doses) offers strong protection against Alpha (B.1.1.7) with 13 out of 15 studies reporting more than 84% efficacy. The results are not conclusive against the Beta (B.1.351) variant for fully vaccinated individuals with 4 out of 7 studies reporting efficacies between 22 and 60% and 3 out of 7 studies reporting efficacies between 75 and 100%. Protection against Gamma (P.1) variant was lower than 50% according to two studies in fully vaccinated individuals. The data on Delta (B.1.617.2) variant is limited but indicates lower protection compared to other variants.

The Impact of COVID-19 Vaccination on Anxiety Levels of Turkish Dental Professionals and Their Attitude in Clinical Care: A Cross-Sectional Study

Background: The current study aimed to assess the anxiety and fear levels and the attitude towards clinical care, such as the use of personal protective equipment and number of patients examined, before and after COVID-19 vaccination among Turkish dental professionals. Methods: A questionnaire including socio-demographical characteristics and clinical data regarding the number of patients, the use of personal protective equipment, vaccine confidence interval, positive or negative COVID-19 diagnosis, and fear and anxiety levels were examined. Results: A total of 475 dentists (196 men and 279 women) participated. Overall, the vaccination had a positive effect on the decrease of fear and anxiety levels of dental professionals. It was observed that the number of interventional procedures significantly increased after vaccination. Besides that, the amount of personal protective equipment used in patients, especially after the vaccination, has decreased. Conclusion: Despite the positive effects of vaccination on the anxiety levels of dental professionals, protective measurements should further be the main concern, regardless of the vaccination status of both the dental professional and the patient.

Accelerated COVID-19 vaccine development: milestones, lessons, and prospects

The development of effective vaccines to combat infectious diseases is a complex multi-year and multi-stakeholder process. To accelerate the development of vaccines for coronavirus disease 2019 (COVID-19), a novel pathogen emerging in late 2019 and spreading globally by early 2020, the United States government (USG) mounted an operation bridging public and private sector expertise and infrastructure. The success of the endeavor can be seen in the rapid advanced development of multiple vaccine candidates, with several demonstrating efficacy and now being administered around the globe. Here, we review the milestones enabling the USG-led effort, the methods utilized, and ensuing outcomes. We discuss the current status of COVID-19 vaccine development and provide a perspective for how partnership and preparedness can be better utilized in response to future public-health pandemic emergencies.