Simulation modeling assessment and improvement of a COVID-19 mass vaccination center operations

The development of safe and effective vaccines against COVID-19 has been a turning point in the international effort to control this disease. However, vaccine development is only the first phase of the COVID-19 vaccination process. Correct planning of mass vaccination is important for any policy to immunize the population. For this purpose, it is necessary to set up and properly manage mass vaccination centers. This paper presents a discrete event simulation model of a real COVID-19 mass vaccination center located in Sfax, Tunisia. This model was used to evaluate the management of this center through different performance measures. Three person's arrival scenarios were considered and simulated to verify the response of this real vaccination center to arrival variability. A second model was proposed and simulated to improve the performances of the vaccination center. Like the first model, this one underwent the same evaluation process through the three arrivals scenarios. The simulation results show that both models respond well to the arrival's variability. Indeed, most of the arriving persons are vaccinated on time for all the studied scenarios. In addition, both models present moderate average vaccination and waiting times. However, the average utilization rates of operators are modest and need to be improved. Furthermore, both simulation models show a high average number of persons present in the vaccination center, which goes against the respect of the social distancing condition. Comparison between the two simulation models shows that the proposed model is more efficient than the actual one. [ FROM AUTHOR] Copyright of Simulation is the property of Sage Publications, Ltd. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full . (Copyright applies to all s.)

Effect of COVID-19 vaccination on mortality by COVID-19 and on mortality by other causes, the Netherlands, January 2021-January 2022.

BACKGROUND: We aimed to estimate vaccine effectiveness (VE) against COVID-19 mortality, and to explore whether an increased risk of non-COVID-19 mortality exists in the weeks following a COVID-19 vaccine dose. METHODS: National registries of causes of death, COVID-19 vaccination, specialized health care and long-term care reimbursements were linked by a unique person identifier using data from 1 January 2021 to 31 January 2022. We used Cox regression with calendar time as underlying time scale to, firstly, estimate VE against COVID-19 mortality after primary and first booster vaccination, per month since vaccination and, secondly, estimate risk of non-COVID-19 mortality in the 5 or 8 weeks following a first, second or first booster dose, adjusting for birth year, sex, medical risk group and country of origin. RESULTS: VE against COVID-19 mortality was > 90 % for all age groups two months after completion of the primary series. VE gradually decreased thereafter, to around 80 % at 7-8 months post-primary series for most groups, and around 60 % for elderly receiving a high level of long-term care and for people aged 90+ years. Following a first booster dose, the VE increased to > 85 % in all groups. The risk of non-COVID-19 mortality was lower or similar in the 5 or 8 weeks following a first dose compared to no vaccination, as well as following a second dose compared to one dose and a booster compared to two doses, for all age and long-term care groups. CONCLUSION: At the population level, COVID-19 vaccination greatly reduced the risk of COVID-19 mortality and no increased risk of death from other causes was observed.

Prevalence, risk factors, and vaccine effectiveness of COVID-19 infection in thai children, adolescents, and young adults in the omicron era.

Background and objectives: The study of prevalence, risk factors, and vaccine effectiveness (VE) in children, adolescents, and young adults during the Omicron era has been limited, making this the objectives of the study. Methods: A prospective, test-negative case-control study was conducted on patients aged 0-24 years old classified as patients under investigation (PUI) from January to May 2022. PUI with positive RT-PCR within 14 days were classified as cases, whilst PUI with negative RT-PCR in 14 days were controls. Univariate and multivariate analyses determined risk factors; VE was calculated using [1-adjusted odds ratio (OR)] × 100. Results: The final analyses included 3,490 patients with a PUI infection rate of 45.6%. Heterologous vaccination regimens, including inactivated vaccines, viral vectors, and mRNA were utilized during the study period. A total of 2,563 patients (73.5%) had received at least 2 vaccine doses, regardless of regimen. Male gender and household infections were independent risk factors for the development of infection, with an adjusted OR of 1.55 and 1.45, respectively. Underlying comorbidities and obesity were not significantly associated with the development of infection. Patients with underlying comorbidities were more likely to have at least moderate severity of infection with the adjusted OR of 3.07. Age older than 11 years was associated with lower infection risk and development of at least moderate infection with adjusted OR of 0.4 and 0.34, respectively. Vaccinated participants also had a lower risk of developing at least moderate infection: adjusted OR of 0.40. The adjusted VE of any vaccination regimen for infection prevention for one, two, three, or more than four doses was 21.8%, 30.6%, 53.5%, and 81.2%, respectively. The adjusted VE of any vaccination regimen for prevention of at least moderate severity of the disease for one, two, three, or more than four doses was 5.7%, 24.3% 62.9%, and 90.6%, respectively. Conclusion: Disease prevalence among PUI was substantially high during the Omicron wave. A two-dose vaccination regimen does not appear sufficient to ensure protection against infection.

Risk of breakthrough SARS-CoV-2 infection and clinical outcomes among vaccinated patients with type 2 diabetes.

AIM: To explore the risk of breakthrough infection among patients with type 2 diabetes (T2D) and risk of severe clinical outcomes after SARS-CoV-2 infection according to vaccination status. MATERIALS AND METHODS: We conducted a population-based cohort study using South Korea's linked database of nationwide COVID-19 registry and claims data between 2018 and 2021. Hazard ratios (HRs) and 95% confidence intervals (CIs) for breakthrough infections were measured in 1:1 propensity-score (PS)-matched fully vaccinated patients with versus without T2D (full-vaccination cohort), and HRs for all-cause mortality, intensive care unit (ICU) admission/mechanical ventilation (MV) use, and hospitalizations after SARS-CoV-2 infection were measured in 1:1 PS-matched T2D patients with versus without full-vaccination (T2D cohort). RESULTS: After 1:1 PS matching, 2 109 970 patients with and without T2D were identified (age 63.5 years; 50.9% male). Patients with T2D showed an increased risk of breakthrough infections compared to those without T2D (HR 1.10, 95% CI 1.06-1.14). The increased risk of breakthrough infections was more notable among T2D patients receiving insulin treatment. However, the risk of severe COVID-19 outcomes was lower in fully vaccinated T2D patients compared with unvaccinated T2D patients (all-cause mortality: HR 0.54, 95% CI 0.43-0.67; ICU admission/MV use: HR 0.31, 95% CI 0.23-0.41; hospitalization: HR 0.73, 95% CI 0.68-0.78). CONCLUSIONS: While patients with T2D remain a vulnerable population to SARS-CoV-2 infection even after full-vaccination, full-vaccination was associated with a lower risk of adverse clinical outcomes after SARS-CoV-2 infection. These findings support the guidelines recommending patients with T2D as a priority vaccination group.

Selection Effects and COVID-19 Mortality Risk after Pfizer vs. Moderna Vaccination: Evidence from Linked Mortality and Vaccination Records.

Prior research generally finds that the Pfizer-BioNTech (BNT162b2) and Moderna (mRNA1273) COVID-19 vaccines provide similar protection against mortality, sometimes with a Moderna advantage due to slower waning. However, most comparisons do not address selection effects for those who are vaccinated and with which vaccine. We report evidence on large selection effects, and use a novel method to control for these effects. Instead of directly studying COVID-19 mortality, we study the COVID-19 excess mortality percentage (CEMP), defined as the COVID-19 deaths divided by non-COVID-19 natural deaths for the same population, converted to a percentage. The CEMP measure uses non-COVID-19 natural deaths to proxy for population health and control for selection effects. We report the relative mortality risk (RMR) for each vaccine relative to the unvaccinated population and to the other vaccine, using linked mortality and vaccination records for all adults in Milwaukee County, Wisconsin, from 1 April 2021 through 30 June 2022. For two-dose vaccinees aged 60+, RMRs for Pfizer vaccinees were consistently over twice those for Moderna, and averaged 248% of Moderna (95% CI = 175%,353%). In the Omicron period, Pfizer RMR was 57% versus 23% for Moderna. Both vaccines demonstrated waning of two-dose effectiveness over time, especially for ages 60+. For booster recipients, the Pfizer-Moderna gap is much smaller and statistically insignificant. A possible explanation for the Moderna advantage for older persons is the higher Moderna dose of 100 µg, versus 30 µg for Pfizer. Younger persons (aged 18-59) were well-protected against death by two doses of either vaccine, and highly protected by three doses (no deaths among over 100,000 vaccinees). These results support the importance of a booster dose for ages 60+, especially for Pfizer recipients. They suggest, but do not prove, that a larger vaccine dose may be appropriate for older persons than for younger persons.

Effectiveness and Safety of Inactivated SARS-CoV-2 Vaccine (BBIBP-CorV) among Healthcare Workers: A Seven-Month Follow-Up Study at Fifteen Central Hospitals.

BACKGROUND: During a pandemic, healthcare workers are at high risk of contracting COVID-19. To protect these important individuals, it is highly recommended that they receive the COVID-19 vaccine. Our study focused on evaluating the safety and efficacy of Egypt's first approved vaccine, the Sinopharm vaccine (BBIBP-CorV), and comparing these findings with other vaccines. METHODS: An observational study was conducted in fifteen triage and isolation hospitals, from the 1st of March until the end of September 2021. The study included fully vaccinated and unvaccinated participants, and we measured vaccine effectiveness (using 1-aHR), the incidence rate of severely to critically ill hospitalized cases, COVID-19-related work absenteeism, and the safety of the vaccine as outcomes. RESULTS: Of the 1364 healthcare workers who were interviewed, 1228 agreed to participate. After taking the hazard ratio into account, the vaccine effectiveness was found to be 67% (95% CI, 80-43%) for symptomatic PCR-confirmed cases. The incidence rate ratio for hospitalization was 0.45 (95% CI, 0.15-1.31) in the vaccinated group compared to the unvaccinated group, and there was a significant reduction in absenteeism among the vaccinated group (p < 0.007). Most adverse events were mild and well tolerated. Vaccinated pregnant and lactating mothers did not experience any sentinel adverse events. CONCLUSION: Our study found that the BBIBP-CorV vaccine was effective in protecting healthcare workers from COVID-19.

Clinical Characteristics and Outcomes of Vaccinated VS Non-Vaccinated Critically Ill COVID-19 Patients: Retrospective Observation Study.

Objective: We aim to identify the clinical characteristics and outcome of vaccine breakthrough infection in critically ill COVID-19 patients and to compare the clinical course of disease between vaccinated and non-vaccinated patients. Methods: A retrospective review of all adult patients aged ≥18 years admitted to the ICU in King Fahd Hospital of the University in Saudi Arabia with positive COVID-19 RT-PCR test between the period of January 1st to August 31st, 2021, were included. The recruited patients were grouped in to "vaccinated and non-vaccinated group" based on their immunization status. The demographic data, co-morbidities, modality of oxygen support, ICU length of stay (ICU LOS) and mortality were collected and analyzed. Results: A total of 167 patients were included. Seventy-two patients (43%) were vaccinated. Cardiovascular diseases were higher among the vaccinated group (33.3% vs 12.6%, p value <0.001). Requirements of Non-invasive ventilation was significantly lower in vaccinated group compared to non-vaccinated group (73.6% vs 91.6%, p value <0.011). The rates of intubation were similar between both groups. The total intubation days was longer in non-vaccinated patients compared to vaccinated patients and the median duration of intubation was 8 days vs 2 days, respectively (p value 0.027). In subgroup analysis, the P/F ratio was significantly higher in patients who received two doses of vaccine compared to single dose (p value <0.002). Conclusion: In critically ill COVID-19 patients, the vaccinated group has significantly less need for Non-invasive ventilation, fewer intubation days and less hypoxia compared to non-vaccinated patients. We recommend more policies and public education nationwide and worldwide to encourage vaccination and raise awareness of the general population.

Real-World Effectiveness of Four Types of COVID-19 Vaccines.

BACKGROUND: There is a scarcity of evidence regarding the real-world effectiveness of coronavirus disease 2019 (COVID-19) vaccines. This was the first study to evaluate the effectiveness of four types of vaccines against asymptomatic and symptomatic infection, and COVID-19 outcomes among the general population. METHODS: This was a matched comparison group quasi-experimental study conducted in Jordan between 1 January and 29 August 2021. In the first part of the study, 1200 fully vaccinated individuals were matched with 1200 unvaccinated control participants. In order to measure vaccine effectiveness, the infection rates of both vaccinated and unvaccinated groups were calculated. The second part of the study included measuring specific anti-SARS CoV-2 immune cells and antibodies. RESULTS: BNT162b2 (Pfizer, New York, NY, USA) showed a significantly higher effectiveness against asymptomatic COVID-19 infection (91.7%) and hospitalization (99.5%) than BBIBP-CorV (Sinopharm, Beijing, China) (88.4% and 98.7%, respectively) and ChAdOx1 nCoV-19 (AstraZeneca, Cambridge, UK) (84.3%, and 98.9%, respectively). The effectiveness rates of the Sputnik V (Gamaleya Research Institute, Moscow, Russia) vaccine against asymptomatic, symptomatic, and hospitalization were 100%, 100%, and 66.7%, respectively. The highest median anti-spike (S) IgG values were seen in individuals who received BNT162b2 (2.9 AU/mL) and ChAdOx1 nCoV-19 (2.8 AU/mL) vaccines. The levels of anti-S IgG were significantly decreased after 7 months of vaccination with BNT162b2 and BBIBP-CorV. There were significant decreases in the median number of neutralizing antibodies one month and seven months after receiving BNT162b2 (from 88.5 to 75.2 4 Bioequivalent Allergen Unit per milliliter/mL), BBIBP-CorV (from 69.5 to 51.5 BAU/mL), and ChAdOx1 nCoV-19 (from 69.2 to 58.BAU/mL) vaccines. The highest percentage of T cells specific to COVID-19 vaccine was found in individuals who received BNT162b2 (88.5%). CONCLUSION: All four vaccines evaluated in this study showed effectiveness against asymptomatic COVID-19 infection, symptomatic infection, hospitalization, and death. Furthermore, BNT162b2, BBIBP-CorV, and ChAdOx1 nCoV-19 induced high levels of immunology markers within one month of vaccination.

Prior SARS-CoV-2 infection and COVID-19 vaccine effectiveness against outpatient illness during widespread circulation of SARS-CoV-2 Omicron variant, US Flu VE network.

BACKGROUND: We estimated combined protection conferred by prior SARS-CoV-2 infection and COVID-19 vaccination against COVID-19-associated acute respiratory illness (ARI). METHODS: During SARS-CoV-2 Delta (B.1.617.2) and Omicron (B.1.1.529) variant circulation between October 2021 and April 2022, prospectively enrolled adult patients with outpatient ARI had respiratory and filter paper blood specimens collected for SARS-CoV-2 molecular testing and serology. Dried blood spots were tested for immunoglobulin-G antibodies against SARS-CoV-2 nucleocapsid (NP) and spike protein receptor binding domain antigen using a validated multiplex bead assay. Evidence of prior SARS-CoV-2 infection also included documented or self-reported laboratory-confirmed COVID-19. We used documented COVID-19 vaccination status to estimate vaccine effectiveness (VE) by multivariable logistic regression by prior infection status. RESULTS: Four hundred fifty-five (29%) of 1577 participants tested positive for SARS-CoV-2 infection at enrollment; 209 (46%) case-patients and 637 (57%) test-negative patients were NP seropositive, had documented previous laboratory-confirmed COVID-19, or self-reported prior infection. Among previously uninfected patients, three-dose VE was 97% (95% confidence interval [CI], 60%-99%) against Delta, but not statistically significant against Omicron. Among previously infected patients, three-dose VE was 57% (CI, 20%-76%) against Omicron; VE against Delta could not be estimated. CONCLUSIONS: Three mRNA COVID-19 vaccine doses provided additional protection against SARS-CoV-2 Omicron variant-associated illness among previously infected participants.

Vaccine effectiveness against SARS-CoV-2 Delta and Omicron infection and infectiousness within households in the Netherlands between July 2021 and August 2022.

INTRODUCTION: We aimed to estimate vaccine effectiveness against infection (VE-infection) and against further transmission (VE-infectiousness) in a household setting during Delta and Omicron. Knowing these effects can aid policy makers in deciding which groups to prioritize for vaccination. METHODS: Participants with a positive SARS-CoV-2 test were asked about COVID-19 vaccination status and SARS-CoV-2 testing of their household members one month later. VE-infection and VE-infectiousness was estimated using GEE logistic regression adjusting for age, vaccination status, calendar week and household size. RESULTS: 3,399 questionnaires concerning 4,105 household members were included. During the Delta-period, VE-infection of primary series was 47% (95% CI: -27%; 78%) and VE-infectiousness of primary series was 70% (95% CI: 28%; 87%). During the Omicron-period, VE-infection was -36% (95% CI: -88%; 1%) for primary series and -28% (95% CI: -77%; 7%) for booster vaccination. The VE-infectiousness was 45% (95% CI: -14%; 74%) for primary series and 64% (95% CI: 31%; 82%) for booster vaccination. DISCUSSION: Our study shows that COVID-19 vaccination is effective against infection with SARS-CoV-2 Delta and against infectiousness of SARS-CoV-2 Delta and Omicron. Estimation of VE against infection with SARS-CoV-2 Omicron was limited by several factors. Our results support booster vaccination for those in close contact with vulnerable people to prevent transmission.

Effectiveness of COVID-19 Vaccines at Preventing Emergency Department or Urgent Care Encounters and Hospitalizations Among Immunocompromised Adults: An Observational Study of Real-World Data Across 10 US States from August-December 2021

Background Immunocompromised (IC) persons are at increased risk for severe COVID-19 outcomes and are less protected by 1-2 COVID-19 vaccine doses than are immunocompetent (non-IC) persons. We compared vaccine effectiveness (VE) against medically attended COVID-19 of 2-3 mRNA and 1-2 viral-vector vaccine doses between IC and non-IC adults. Methods Using a test-negative design among eight VISION Network sites, VE against laboratory-confirmed COVID-19–associated emergency department (ED) or urgent care (UC) events and hospitalizations from 26 August-25 December 2021 was estimated separately among IC and non-IC adults and among specific IC condition subgroups. Vaccination status was defined using number and timing of doses. VE for each status (versus unvaccinated) was adjusted for age, geography, time, prior positive test result, and local SARS-CoV-2 circulation. Results We analyzed 8,848 ED/UC events and 18,843 hospitalizations among IC patients and 200,071 ED/UC events and 70,882 hospitalizations among non-IC patients. Among IC patients, 3-dose mRNA VE against ED/UC (73% [95% CI: 64-80]) and hospitalization (81% [95% CI: 76-86]) was lower than that among non-IC patients (ED/UC: 94% [95% CI: 93-94];hospitalization: 96% [95% CI: 95-97]). Similar patterns were observed for viral-vector vaccines. Transplant recipients had lower VE than other IC subgroups. Conclusions During B.1.617.2 (Delta) variant predominance, IC adults received moderate protection against COVID-19–associated medical events from three mRNA doses, or one viral-vector dose plus a second dose of any product. However, protection was lower in IC versus non-IC patients, especially among transplant recipients, underscoring the need for additional protection among IC adults.

Age-dependent final size equation to anticipate mortality impact of COVID-19 in China.

Before reopening society in December 2022, China had not achieved sufficiently high vaccination coverage among people aged 80 years and older, who are vulnerable to severe infection and death owing to COVID-19. Suddenly ending the zero-COVID policy was anticipated to lead to substantial mortality. To investigate the mortality impact of COVID-19, we devised an age-dependent transmission model to derive a final size equation, permitting calculation of the expected cumulative incidence. Using an age-specific contact matrix and published estimates of vaccine effectiveness, final size was computed as a function of the basic reproduction number, R0. We also examined hypothetical scenarios in which third-dose vaccination coverage was increased in advance of the epidemic, and also in which mRNA vaccine was used instead of inactivated vaccines. Without additional vaccination, the final size model indicated that a total of 1.4 million deaths (half of which were among people aged 80 years and older) were anticipated with an assumed R0 of 3.4. A 10% increase in third-dose coverage would prevent 30,948, 24,106, and 16,367 deaths, with an assumed second-dose effectiveness of 0%, 10%, and 20%, respectively. With mRNA vaccine, the mortality impact would have been reduced to 1.1 million deaths. The experience of reopening in China indicates the critical importance of balancing pharmaceutical and non-pharmaceutical interventions. Ensuring sufficiently high vaccination coverage is vital in advance of policy changes.

Humoral Immunity Response of COVID-19 Vaccine and Adverse Effect Among Solid Cancer Patient: A Prospective Cross-Sectional Study

Background and aim: Patients with cancer are at an increased risk for morbidity and mortality from coronavirus disease 2019 (COVID-19). Although cancer patients should have the priority for vaccination against SARS-CoV-2, data on vaccine immunogenicity and safety against severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) are scarce. The aim of this prospective study was to investigate the safety and efficacy of Pfizer-BioNTech's COVID-19 vaccine (BNT162b2) in solid cancer patients receiving active chemotherapy. Methods: We evaluated the safety and immunogenicity of BNT162b2 vaccine in 51 solid cancer patients undergoing active therapy in Azadi Hematology -- Oncology center in Duhok city. The serum IgG antibody titer for S1 protein was measured by using VIDAS at pre-vaccination and 14-30 days after the second dose. The adverse events of vaccine were collected by a standardized questionnaire. Results: From 51 patients, most were metastatic (35, 68.63%), stage IV (28,54.90%). Females were more than males (36, 70.59%), (15, 29.41%) respectively. The most common types of cancer were breast (16, 31.37%), colon (8, 15.69%). Anti-S1 antibody level was significantly high. Fifty patients were seropositive (98.04%). Vaccine showed high safety profile;most of the adverse effects were mild to moderate. Most of the side effects recovered over 1-3 days. Injection site reactions were the most frequent local adverse effects after first and second doses, 17.6% and 52.9, respectively. On the other hand, most prevalent systemic adverse effects were fever (17.65%, 44.00%), headache (16.00%, 21.57%), and myalgia (35.29%, 5.88%) after first and second doses, respectively. Conclusion: the COVID-19 vaccine acceptance rate was high (89.36%). The seropositivity, following BNT162b2 vaccine, was extremely high (98.04) among cancer patient on active chemotherapy. The vaccine showed good tolerance and an excellent safety profile. Hence, it should be strongly recommended for such a risky vulnerable group to SARSCoV- 2. Breast cancer showed significantly higher seropositivity in comparison to colon cancer, which may be attributed to chemotherapy regimen, degree of immunosuppression, and gender factors. [ FROM AUTHOR] Copyright of Journal of Pharmaceutical Negative Results is the property of ResearchTrentz and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full . (Copyright applies to all s.)

Assessment Of Covid-19 Vaccination Literacy And Post Vaccination Effects Among Vaccinated Population: A Cross-Sectional Online Survey Study

BACKGROUND: A safe and effective vaccine against COVID-19 has become a public health priority. However only a few studies have been conducted to investigate the post vaccination symptoms and awareness among the public about the vaccination. This study aimed to assess the COVID-19 vaccination literacy and post vaccination effects among the vaccinated population in India. METHODOLOGY: A descriptive cross-sectional study was conducted with a convenience sample of the adult population in India. Data was collected through an online anonymous questionnaire. We used Google forms an online survey platform, to publish the questionnaire and manually generated the answer URL link to the eligible candidates. RESULTS: A total of 533 responses were collected. Among the participants, 463 (86.90%) were aged between 18 and 40 years old. Of which 289 (54.2%) were male and 244 (45.8%) were female participants. Among the respondents 374 (70.2%) completed both the doses of vaccine. 498 (93.4%) participants took the vaccination willingly and 35 (6.6%) participants were forced to get vaccinated. Body ache 327 (61.4%), Fever 307 (57.6%), headache 211 (39.6%) and alopecia 70 (14%) were the most commonly reported post vaccination symptoms. CONCLUSION: Overall, our study demonstrated that there was a high willingness to accept COVID-19 vaccine in India and the rate of infection with COVID-19 has been reduced after vaccination which proves that the vaccine is efficient. The rate of people getting hospitalized due COVID-19 has been drastically reduced. Cold, cough, mild hypersensitivity reactions were also been reported as post vaccination symptoms and no serious adverse effects were reported so far due to vaccination which proves that the vaccine is safe. [ FROM AUTHOR] Copyright of Journal of Pharmaceutical Negative Results is the property of ResearchTrentz and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full . (Copyright applies to all s.)

SARS-CoV-2 Vaccine Effectiveness against Omicron Variant in Infection-Naive Population, Australia, 2022.

SARS-CoV-2 transmission in Western Australia, Australia, was negligible until a wave of Omicron variant infections emerged in February 2022, when >90% of adults had been vaccinated. This unique pandemic enabled assessment of SARS-CoV-2 vaccine effectiveness (VE) without potential interference from background immunity from prior infection. We matched 188,950 persons who had a positive PCR test result during February-May 2022 to negative controls by age, week of test, and other possible confounders. Overall, 3-dose VE was 42.0% against infection and 81.7% against hospitalization or death. A primary series of 2 viral-vectored vaccines followed by an mRNA booster provided significantly longer protection against infection >60 days after vaccination than a 3-dose series of mRNA vaccine. In a population free from non-vaccine-derived background immunity, vaccines against the ancestral spike protein were ≈80% effective for preventing serious outcomes from infection with the SARS-CoV-2 Omicron variant.

Timing and Magnitude of the Second Wave of the COVID-19 Omicron Variant - 189 Countries and Territories, November 2021 to February 2023.

What is already known about this topic?: The first nationwide wave of coronavirus disease 2019 (COVID-19), driven by the Omicron variant, has largely subsided. However, subsequent epidemic waves are inevitable due to waning immunity and the ongoing evolution of the severe acute respiratory syndrome coronavirus 2. What is added by this report?: Insights gleaned from other nations offer guidance regarding the timing and scale of potential subsequent waves of COVID-19 in China. What are the implications for public health practice?: Understanding the timing and magnitude of subsequent waves of COVID-19 in China is crucial for forecasting and mitigating the spread of the infection.

Waning effectiveness against COVID-19-related hospitalization, severe complications, and mortality with two to three doses of CoronaVac and BNT162b2: a case-control study.

BACKGROUND: This study aims to evaluate waning effectiveness against severe and fatal COVID-19 with two to three doses of CoronaVac/BNT162b2, where data are limited. METHODS: A case-control study included individuals aged ≥18 years, unvaccinated or received two to three doses of CoronaVac/BNT162b2, using electronic healthcare databases in Hong Kong. Those with first COVID-19-related hospitalization, severe complications, or mortality between 1 January and 15 August 2022 were defined as cases and matched with up-to-10 controls by age, sex, index date, and Charlson Comorbidity Index. Vaccine effectiveness (VE) against COVID-19-related outcomes was estimated at different time intervals from second and third-dose vaccination (0-13 up-to 210-240 days) using conditional logistic regression adjusted for comorbidities and medications. RESULTS: By 211-240 days after second dose, VE against COVID-19-related hospitalization reduced to 46.6% (40.7-51.8%) for BNT162b2 and 36.2% (28.0-43.4%) for CoronaVac, and VE against COVID-19-related mortality were 73.8% (55.9-84.4%) and 76.6% (60.8-86.0%). After third dose, VE against COVID-19-related hospitalization decreased from 91.2% (89.5-92.6%) for BNT162b2 and 76.7% (73.7-79.4%) for CoronaVac at 0-13 days, to 67.1% (60.4-72.6%) and 51.3% (44.2-57.5%) at 91-120 days. VE against COVID-19-related mortality for BNT162b2 remained high from 0-13 days [98.2% (95.0-99.3%)] to 91-120 days [94.6% (77.7-98.7%)], and for CoronaVac reduced from 0-13 days [96.7% (93.2-98.4%)] to 91-120 days [86.4% (73.3-93.1%)]. CONCLUSIONS: Significant risk reduction against COVID-19-related hospitalization and mortality after CoronaVac or BNT162b2 vaccination was observed for >240 and >120 days after second and third doses compared to unvaccinated, despite significant waning over time. Timely administration of booster doses could provide higher levels of protection.

Number of COVID-19 hospitalisations averted by vaccination: Estimates for the Netherlands, January 6, 2021 through August 30, 2022.

BACKGROUND: Vaccines against COVID-19 have proven effective in preventing COVID-19 hospitalisation. In this study, we aimed to quantify part of the public health impact of COVID-19 vaccination by estimating the number of averted hospitalisations. We present results from the beginning of the vaccination campaign ('entire period', January 6, 2021) and a subperiod starting at August 2, 2021 ('subperiod') when all adults had the opportunity to complete their primary series, both until August 30, 2022. METHODS: Using calendar-time specific vaccine effectiveness (VE) estimates and vaccine coverage (VC) by round (primary series, first booster and second booster) and the observed number of COVID-19 associated hospitalisations, we estimated the number of averted hospitalisations per age group for the two study periods. From January 25, 2022, when registration of the indication of hospitalisation started, hospitalisations not causally related to COVID-19 were excluded. RESULTS: In the entire period, an estimated 98,170 (95 % confidence interval (CI) 96,123-99,928) hospitalisations were averted, of which 90,753 (95 % CI 88,790-92,531) were in the subperiod, representing 57.0 % and 67.9 % of all estimated hospital admissions. Estimated averted hospitalisations were lowest for 12-49-year-olds and highest for 70-79-year-olds. More admissions were averted in the Delta period (72.3 %) than in the Omicron period (63.4 %). CONCLUSION: COVID-19 vaccination prevented a large number of hospitalisations. Although the counterfactual of having had no vaccinations while maintaining the same public health measures is unrealistic, these findings underline the public health importance of the vaccination campaign to policy makers and the public.

COVID-19 outbreak in a religious village community in Republic of Korea and risk factors for transmission.

OBJECTIVES: This study aimed to assess the scale and transmission patterns of coronavirus disease 2019 (COVID-19) in a religious village community in South Korea, to determine the risk factors of transmission, and to evaluate vaccine effectiveness. METHODS: An epidemiological survey was conducted, and data were collected and analyzed from 602 villagers in the religious village community. Multivariate logistic regression analysis was used to identify the risk factors for COVID-19 transmission and to evaluate vaccine effectiveness. RESULTS: The outbreak attack rate was 72.1% (434/602). The attack rate was high among women in their 60s, the unemployed, residents living near religious facility (<500 m), and the unvaccinated. Age, the distance between religious facility and residences, and the absence of vaccination were identified as risk factors for transmission. Vaccine effectiveness was 49.0%, and the highest effectiveness was seen in the age group of 59 years or younger (65.8%). CONCLUSION: This village community was isolated, with little communication with the outside world. However, the frequency of close contact between residents was relatively high, contributing to the spread of COVID-19 in the village even with relatively short exposure. Vaccination rates in the village community were also lower than those in the general public. Public health authorities should consider the potential impact of cultural factors, including religion, that could lead to the exponential spread of COVID-19 in closed village communities.

The effectiveness of COVID-19 vaccination against all-cause mortality in patients with type 2 diabetes mellitus: The observation during the initial period of the cancellation of the "Dynamic Zero Policy" in mainland China.

AIMS: This study aims to assess the effectiveness of COVID-19 vaccination against all-cause death in patients with type 2 diabetes mellitus (T2DM). METHODS: Subjects were patients with T2DM who were administered by general practitioner (GP). Use electronic exchange platform to obtain the information on COVID-19 vaccination, all-cause deaths and risk factors. Logistic regression models were used to calculate the odd ratio (OR) and 95% CI for the association between COVID-19 vaccination and mortality. The vaccine effectiveness (VE) was calculated as (1- adjusted OR) × 100%. RESULTS: A total of 26,916 subjects had 53.81%, 17.65%, and 23.43% coverage for the booster, full, and partial COVID-19 vaccination, reported 328 deaths and a mortality of 1.2%. The adjusted OR (95%CI) was 0.85(0.60-1.21) for those received partial vaccination, 0.31(0.22-0.43) for those received full vaccination, and 0.12(0.08-0.18) for those received booster vaccination, compared to the unvaccinated individuals. The VE (95%CI) was 88.00%(82.30-91.80) of booster vaccination, 69.30%(56.60-78.30) of full vaccination, and 17.60%(-17.10-42.00) of partial vaccination. CONCLUSION: COVID-19 vaccination could effectively prevent the all-cause death in patients with T2DM during the omicron variant outbreak period, after the cancellation of the "Dynamic Zero Policy" in mainland China.