scholarly journals How Large Fraction of A Population Must be Vaccinated before A Disease is Controlled?

2022 ◽  
Author(s):  
Robin Halamicek ◽  
Dirk W Schubert ◽  
Fritjof Nilsson
Keyword(s):  
Vaccine Coverage ◽  
Large Fraction ◽  
Vaccine Dose ◽  
Vaccination Rate ◽  
Basic Reproduction Ratio ◽  
Mathematical Equation ◽  
Reproduction Ratio ◽  
Vaccination Rates ◽  
Crucial Question ◽  
Modelling Study

Abstract The ongoing Covid-19 pandemic has already caused more than 5 million casualties despite hard restrictions and relatively high vaccine coverage in many countries. The crucial question is therefore, how large vaccination rate and how severe restrictions are required to terminate the spread of the decease, assuming that the vaccine efficiency and the basic reproduction ratio (R0) are known? To answer this question, a mathematical equation was applied to visualize the required vaccination level as function of vaccine efficiency, restriction efficiency and basic reproduction ratio (R0). In addition to the modelling study, Covid-19 data from Europe was collected during 19/11-26/11 (2021) to assess the relation between vaccination rate and incidence. The analysis indicates that a vaccination rate of ~92% (2 doses) is required to stop Delta (B.1.617.2) without severe restrictions, under conditions like those in Europe late November 2021. A third vaccine dose, improved vaccines, higher vaccination rates and/or stronger restrictions will be required to force Omicron (B.1.1.529) to expire without infecting a large fraction of the population.

scholarly journals How Large Fraction of A Population Must be Vaccinated before A Disease is Controlled?

2022 ◽  
Author(s):  
Robin Halamicek ◽  
Dirk W Schubert ◽  
Fritjof Nilsson
Keyword(s):  
Vaccine Coverage ◽  
Large Fraction ◽  
Vaccine Dose ◽  
Vaccination Rate ◽  
Basic Reproduction Ratio ◽  
Mathematical Equation ◽  
Reproduction Ratio ◽  
Vaccination Rates ◽  
Crucial Question ◽  
Europe Today

Abstract The ongoing Covid-19 pandemic has already caused more than 5 million casualties despite hard restrictions and relatively high vaccine coverage in many countries. The crucial question is therefore, how large vaccination rate and how severe restrictions are required to terminate the spread of the decease, assuming that the vaccine efficiency and the basic reproduction ratio (R0) are known? To answer this question, a simple mathematical equation was developed to visualize the required vaccination level as function of vaccine efficiency, restriction efficiency and basic reproduction ratio (R0). In addition to the modelling study, Covid-19 data from Europe was collected during 19/11-26/11 (2021) to assess the relation between vaccination rate and incidence. The analysis indicates that a vaccination rate of ~92% (2 doses) is currently required to stop Delta (B.1.617.2) without severe restrictions, using the vaccines that are most common in Europe today. A third vaccine dose, improved vaccines, higher vaccination rates and/or stronger restrictions will be required to force Omicron (B.1.1.529) to expire without infecting a large fraction of the population.

scholarly journals Higher COVID-19 vaccination rates are linked to decreased county-level COVID-19 incidence across USA

2021 ◽  
Author(s):  
Arjun Puranik ◽  
AJ Venkatakrishnan ◽  
Colin Pawlowski ◽  
Bharathwaj Raghunathan ◽  
Eshwan Ramudu ◽  
...  
Keyword(s):  
Incidence Rate ◽  
Vaccine Efficacy ◽  
Vaccine Dose ◽  
The United States ◽  
Vaccination Rate ◽  
Incidence Rates ◽  
P Value ◽  
County Level ◽  
Vaccination Rates ◽  
The Impact

Real world evidence studies of mass vaccination across health systems have reaffirmed the safety1 and efficacy2,3 of the FDA-authorized mRNA vaccines for COVID-19. However, the impact of vaccination on community transmission remains to be characterized. Here, we compare the cumulative county-level vaccination rates with the corresponding COVID-19 incidence rates among 87 million individuals from 580 counties in the United States, including 12 million individuals who have received at least one vaccine dose. We find that cumulative county-level vaccination rate through March 1, 2021 is significantly associated with a concomitant decline in COVID-19 incidence (Spearman correlation ρ = −0.22, p-value = 8.3e-8), with stronger negative correlations in the Midwestern counties (ρ = −0.37, p-value = 1.3e-7) and Southern counties (ρ = −0.33, p-value = 4.5e-5) studied. Additionally, all examined US regions demonstrate significant negative correlations between cumulative COVID-19 incidence rate prior to the vaccine rollout and the decline in the COVID-19 incidence rate between December 1, 2020 and March 1, 2021, with the US western region being particularly striking (ρ = −0.66, p-value = 5.3e-37). However, the cumulative vaccination rate and cumulative incidence rate are noted to be statistically independent variables, emphasizing the need to continue the ongoing vaccination roll out at scale. Given confounders such as different coronavirus restrictions and mask mandates, varying population densities, and distinct levels of diagnostic testing and vaccine availabilities across US counties, we are advancing a public health resource to amplify transparency in vaccine efficacy monitoring (https://public.nferx.com/covid-monitor-lab/vaccinationcheck). Application of this resource highlights outliers like Dimmit county (Texas), where infection rates have increased significantly despite higher vaccination rates, ostensibly owing to amplified travel as a “vaccination hub”; as well as Henry county (Ohio) which encountered shipping delays leading to postponement of the vaccine clinics. This study underscores the importance of tying the ongoing vaccine rollout to a real-time monitor of spatio-temporal vaccine efficacy to help turn the tide of the COVID-19 pandemic.

scholarly journals Impacts of a delayed and slow-paced vaccination on cases and deaths during the COVID-19 pandemic: a modelling study

2021 ◽  
Author(s):  
Gustavo Libotte ◽  
Lucas Anjos ◽  
Regina Célia Cerqueira de Almeida ◽  
Sandra Mara Malta ◽  
Roberto Medronho
Keyword(s):  
Rio De Janeiro ◽  
Technological Development ◽  
Gaussian Process Regression ◽  
Vaccination Rate ◽  
The State ◽  
National Council ◽  
Vaccination Rates ◽  
Whole Process ◽  
Credible Intervals ◽  
Modelling Study

Abstract Background: In Brazil, vaccination has always been cutting across party political and ideological lines, which have delayed its start and brought the whole process into disrepute. Such divergences put the immunisation of the population in the background and create additional hurdles beyond the pandemic, mistrust and scepticism over vaccines.Methods: We conduct a mathematical modelling study to analyse the impacts of late vaccination and with slowly increasing coverage, as well as how harmful it would be if part of the population refused to get vaccinated or missed the second dose. We analyse data from confirmed cases, deaths caused by COVID-19, and vaccination in the state of Rio de Janeiro in the period between March 10, 2020, and October 27, 2021. The classical SIR model is extended to consider the effect of vaccination (efficacy, interval between doses, and vaccination rate) and data sets are regularised using Gaussian Process Regression. The model parameter distributions are estimated using Bayesian inference, aiming to obtain credible intervals in the simulations.Findings: We estimate that if the start of vaccination had been 30 days earlier, combined with efforts to drive vaccination rates up, 31,657 (25,801–35,117) deaths could have been averted. Our results also indicate that the slow pace of vaccination and the low demand for the second dose could cause a resurgence of cases as early as 2022.Interpretation: The government's inaction and lack of a strategic plan to fight the pandemic meant that vaccination started late, leading to thousands of deaths that could have been prevented. Even when reaching the expected vaccination coverage for the first dose, it is still challenging to increase adherence to the second dose and maintain a high vaccination rate to avoid new outbreaks.Funding: Carlos Chagas Filho Foundation for Supporting Research in the State of Rio de Janeiro (FAPERJ) and Brazilian National Council for Scientific and Technological Development (CNPq).

scholarly journals An Extended Susceptible-Exposed-Infected-Recovered (SEIR) Model with Vaccination for Forecasting the COVID-19 Pandemic in Sri Lanka

2021 ◽  
Author(s):  
R.M. Nayani Umesha Rajapaksha ◽  
Millawage Supun Dilara Wijesinghe ◽  
Sujith P. Jayasooriya ◽  
B. M. Indika Gunawardana ◽  
W. M. Prasad Chathuranga Weerasinghe
Keyword(s):  
Sri Lanka ◽  
Compartmental Model ◽  
Vaccine Coverage ◽  
Health Planning ◽  
Local Population ◽  
Vaccination Rate ◽  
Vaccination Rates ◽  
Infected Population ◽  
Potential Vaccine

The role of modelling in predicting the spread of an epidemic is important for health planning and policies. This study aims to apply a compartmental model for predicting the variations of epidemiological parameters in Sri Lanka. We used a dynamic Susceptible-Exposed-Infected-Recovered-Vaccinated (SEIRV) model, and simulated for potential vaccine strategies under a range of epidemic conditions. The predictions were based on different vaccination coverages (5% to 90%), vaccination-rates (1%, 2%, 5%) and vaccine-efficacies (40%, 60%, 80%) under different R0 (2,4,6). We observed how the above dynamics influenced the SEIRV model without COVID-19 vaccination at different R0 values, and estimated the duration, exposed and infected populations. When the R0 was increased, the days of reduction of susceptibility and the days to reach the peak of the infection were reduced gradually. At least 45% vaccine coverage is required for reducing the infected population as early as possible. The results revealed that when R0 is increased in the SEIRV model along with the increase of vaccination efficacy and vaccination rate, the population to be vaccinated is reducing. Thus, the vaccination offers greater benefits to the local population by reducing the time to reach the peak, exposed and infected population through flattening the curves.

scholarly journals Evaluation of a pilot project to increase influenza vaccine coverage in patient with chronic diseases

2020 ◽  
Vol 30 (Supplement_5) ◽  
Author(s):  
L Pinsonneault ◽  
K Demers ◽  
P Dagenais ◽  
G Baron
Keyword(s):  
Influenza Vaccine ◽  
Chronic Diseases ◽  
Vaccine Coverage ◽  
Pilot Project ◽  
Immunosuppressive Drugs ◽  
Vaccination Rate ◽  
Lessons Learned ◽  
Patient Questionnaire ◽  
Vaccination Rates ◽  
Patient Questionnaires

Abstract Background Chronic diseases are a major risk factor for influenza morbidity and mortality. However, influenza vaccine coverage in people with chronic diseases remains low, around 43%, in Quebec, Canada. Various strategies are being tested to improve the vaccination rates for this population. A pilot project was implemented in a rheumatology outpatient clinic during the 2018-19 season to improve vaccination access in this often-immunosuppressed group of patients. All patients having an appointment at the clinic during the vaccination period were systematically invited to see the nurse and offered vaccination if they met the program criteria, namely if they were taking immunosuppressive drugs. Methods Implementation and results of the project were evaluated using mixed methods. Data on vaccination were collected from the nurses' forms and from a patient self-administered questionnaire. Data on implementation was collected through the patient questionnaire and semi-directed interviews with the clinic physicians, the clinic nurse and managers. Results A total of 1135 patients were evaluated by the nurses during the project and 427 completed the patient questionnaire. Total vaccination rate amongst patients seen by the nurses was 63%. Based on patient questionnaires results, vaccination was increased by 46%, as compared to the previous year (52% in 2017-18 vs 76% in 2018-19). The project was well received. Key elements of its success were integration in regular clinic activities, support for the initiative by patients and professionals and some logistic aspects such as preloaded syringes. Barriers were mostly related to excess workload and vaccine management. Conclusions Overall, the project improved vaccination coverage and was considered a success. Lessons learned were used to adjust and spread this initiative to more outpatient clinics using personnel dedicated for vaccination rather than using the clinic nurse. A phase II project was done and evaluated in 2019-2020. Key messages Increasing timely access to vaccination helps to increase influenza vaccine coverage. Managers should plan for the increased workload on clinical and clerical personnel when implementing systematic vaccination offer.

scholarly journals Socioeconomic gradient in COVID-19 vaccination: evidence from Israel

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Mor Saban ◽  
Vicki Myers ◽  
Shani Ben-Shetrit ◽  
Rachel Wilf-Miron
Keyword(s):  
Low Socioeconomic Status ◽  
Vaccine Dose ◽  
Vaccination Rate ◽  
Vaccine Uptake ◽  
Arab Population ◽  
Low Socioeconomic ◽  
Vaccination Rates ◽  
Disadvantaged Communities ◽  
Socioeconomic Gradient ◽  
Neighborhood Ses

Abstract Background Low socioeconomic status (SES) groups have been disproportionately affected by the COVID-19 pandemic. We aimed to examine COVID-19 vaccination rate by neighborhood SES and ethnicity in Israel, a country which has achieved high vaccination rates. Methods Data on vaccinations were obtained from the Israeli Ministry of Health’s open COVID-19 database, for December 20, 2020 to August 31, 2021. Correlation between vaccination rate and neighborhood SES was analyzed. Difference in vaccination rate between the first and second vaccine dose was analyzed by neighborhood SES and ethnicity. Findings A clear socioeconomic gradient was demonstrated, with higher vaccination rates in the higher SES categories (first dose: r = 0.66; second dose: r = 0.74; third dose: r = 0.92). Vaccination uptake was lower in the lower SES groups and in the Arab population, with the largest difference in uptake between Jewish and Arab localities for people younger than 60, and with the gap widening between first and third doses. Conclusions Low SES groups and the Arab ethnic minority demonstrated disparities in vaccine uptake, which were greater for the second and third, compared with the first vaccine dose. Strategies to address vaccination inequity will need to identify barriers, provide targeted information, and include trust-building in disadvantaged communities.

scholarly journals Flu and Pneumococcal Vaccine Coverage in Scleroderma Patients Still Need to Be Prompted: A Systematic Review

Vaccines ◽  
2021 ◽  
Vol 9 (11) ◽  
pp. 1330
Author(s):  
Francesca Rosamilia ◽  
Giovanni Noberasco ◽  
Dario Olobardi ◽  
Andrea Orsi ◽  
Giancarlo Icardi ◽  
...  
Keyword(s):  
Systematic Review ◽  
Vaccine Coverage ◽  
Pneumococcal Vaccination ◽  
Vaccination Rate ◽  
Vaccination Rates ◽  
Increased Risk ◽  
Flu Vaccine ◽  
Vaccination Campaigns ◽  
Low Coverage ◽  
Current Guidelines

Systemic sclerosis (scleroderma, SSc) is an autoimmune connective tissue disease characterized by excessive production of collagen and multiorgan involvement. Scleroderma patients are at increased risk of influenza complications and pneumonia; thus, vaccinations are recommended. This systematic review evaluated the influenza and pneumococcus vaccination coverage for SSc patients. We included all studies from Pubmed reporting on influenza and pneumococcal vaccination rate in Scleroderma patients up to May 2021. The 14 studies thus selected identified a suboptimal vaccination rate in autoimmune and SSc patients, ranging from 28 to 59% for the flu vaccine, and from 11 to 58% for the pneumo vaccine in absence of specific vaccination campaigns, variously considering also other variables such as age, gender, vaccination settings, and possible vaccination campaigns. We also considered the reasons for low coverage and the approaches that might increase the vaccination rates. A lack of knowledge about the importance of vaccination in these patients and their doctors underlined the need to increase the awareness for vaccination in this patients’ category. Current guidelines recommend vaccination in elderly people and people affected by particular conditions that widely overlap with SSc, yet autoimmune diseases are not always clearly mentioned. Improving this suboptimal vaccination rate with clear guidelines is crucial for SSc patients and for clinicians to immunize these categories based principally on the pathology, prior to the age. Recommendations by the immunologist and the direct link to the vaccine providers can highly improve the vaccine coverage.

scholarly journals Influenza Vaccination Status and Its Affecting Factors among Stroke Survivors: Findings from the Korea National Health and Nutrition Examination Survey

Vaccines ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 763
Author(s):  
Eung-Joon Lee ◽  
Oh-Deog Kwon ◽  
Seung-Jae Kim
Keyword(s):  
Influenza Vaccination ◽  
National Health ◽  
Vaccine Coverage ◽  
Vaccination Rate ◽  
Vaccination Program ◽  
Stroke Survivors ◽  
Nutrition Examination Survey ◽  
Affecting Factors ◽  
Vaccination Rates ◽  
Health And Nutrition

Few studies have examined the influenza vaccination rates among stroke survivors despite the importance of vaccines in preventing influenza- and stroke-related complications. Thus, we investigated the vaccination rates and the associated factors among stroke survivors using the representative Korea National Health and Nutrition Examination Survey 2014–2018. We measured and compared the vaccination rates of 591 stroke survivors and 17,997 non-stroke survivors. Multivariate logistic regression analyses of all stroke survivors and age subgroups (<65 and ≥65 years) were performed to identify the factors influencing vaccination. The overall vaccination rate was significantly higher in the stroke survivors (64.8%) than in the non-stroke survivors (41.1%), but it was low compared to global standards. Among stroke survivors aged < 65 years, the rate was low (37.5%), but it improved in those aged ≥ 65 years (85.6%). Age ≥ 65 years, the eligible age for the national free vaccination program was the most prominent predictor of vaccination for all stroke survivors, while smoking was a negative predictor. No significant factors were found in the subgroup analyses according to age (<65 and ≥65 years). Therefore, implementing strategic public health policies, such as expanding the free vaccination program to stroke survivors aged < 65 years, may improve vaccine coverage.

Correlates of Improved Influenza Vaccination of Healthcare Personnel: A Survey of Hospitals in Louisiana

2013 ◽  
Vol 34 (7) ◽  
pp. 723-729 ◽  
Author(s):  
Kayla L. Fricke ◽  
Mariella M. Gastañaduy ◽  
Renee Klos ◽  
Rodolfo E. Bégué
Keyword(s):  
Intensive Care Unit ◽  
Intensive Care ◽  
Influenza Vaccination ◽  
Vaccination Campaign ◽  
Vaccination Rate ◽  
Healthcare Personnel ◽  
Patient Contact ◽  
Hospital Type ◽  
Vaccination Rates ◽  
Item Questionnaire

Objective.To describe practices for influenza vaccination of healthcare personnel (HCP) with emphasis on correlates of increased vaccination rates.Design.Survey.Participants.Volunteer sample of hospitals in Louisiana.Methods.All hospitals in Louisiana were invited to participate. A 17-item questionnaire inquired about the hospital type, patients served, characteristics of the vaccination campaign, and the resulting vaccination rate.Results.Of 254 hospitals, 153 (60%) participated and were included in the 124 responses that were received. Most programs (64%) required that HCP either receive the vaccine or sign a declination form, and the rest were exclusively voluntary (36%); no program made vaccination a condition of employment. The median vaccination rate was 67%, and the vaccination rate was higher among hospitals that were accredited by the Joint Commission; provided acute care; served children, pregnant women, oncology patients, or intensive care unit patients; required a signed declination form; or imposed consequences for unvaccinated HCP (the most common of which was to require that a mask be worn on patient contact). Hospitals that provided free vaccine, made vaccine widely available, advertised the program extensively, required a declination form, and imposed consequences had the highest vaccination rates (median, 86%; range, 81%–91%).Conclusions.The rate of influenza vaccination of HCP remains low among the hospitals surveyed. Recommended practices may not be enough to reach 90% vaccination rates unless a signed declination requirement and consequences are implemented. Wearing a mask is a strong consequence. Demanding influenza vaccination as a condition of employment was not reported as a practice by the participating hospitals.

scholarly journals The Effect of Vaccination Rates on the Infection of COVID-19 under the Vaccination Rate below the Herd Immunity Threshold

2021 ◽  
Vol 18 (14) ◽  
pp. 7491
Author(s):  
Yi-Tui Chen
Keyword(s):  
Infection Rate ◽  
Herd Immunity ◽  
The United States ◽  
Vaccination Rate ◽  
Infection Rates ◽  
Vaccination Rates ◽  
The United Kingdom ◽  
The World ◽  
Almost All ◽  
The Impact

Although vaccination is carried out worldwide, the vaccination rate varies greatly. As of 24 May 2021, in some countries, the proportion of the population fully vaccinated against COVID-19 has exceeded 50%, but in many countries, this proportion is still very low, less than 1%. This article aims to explore the impact of vaccination on the spread of the COVID-19 pandemic. As the herd immunity of almost all countries in the world has not been reached, several countries were selected as sample cases by employing the following criteria: more than 60 vaccine doses per 100 people and a population of more than one million people. In the end, a total of eight countries/regions were selected, including Israel, the UAE, Chile, the United Kingdom, the United States, Hungary, and Qatar. The results find that vaccination has a major impact on reducing infection rates in all countries. However, the infection rate after vaccination showed two trends. One is an inverted U-shaped trend, and the other is an L-shaped trend. For those countries with an inverted U-shaped trend, the infection rate begins to decline when the vaccination rate reaches 1.46–50.91 doses per 100 people.

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