scholarly journals Vaccines alone are no silver bullets: a modeling study on the impact of efficient contact tracing on COVID-19 infection and transmission

Author(s):  
Dhesi Baha Raja ◽  
Nur Asheila Abdul Taib ◽  
Alvin Kuo Jing Teo ◽  
Vivek Jason Jayaraj ◽  
Choo-Yee Ting

AbstractBackgroundThe computer simulation presented in this study aimed to investigate the effect of contact tracing on COVID-19 transmission and infection in the context of rising vaccination rates.MethodsThis study proposed a deterministic SEIRV model with contact tracing and vaccination components. We initialized some parameters using the Malaysian COVID-19 data to inform the model. We defined contact tracing effectiveness as the proportion of contacts of a positive case that was successfully traced and vaccination rate as the proportion of daily doses administered per population in Malaysia. Sensitivity analyses on the untraced and infectious populations were conducted. The study presented in silico findings on multiple scenarios by varying the contact tracing effectiveness and daily vaccination rates.ResultsAt a vaccination rate of 1.4%, a contact tracing with the effectiveness of 70% could delay the peak of untraced asymptomatic cases by 17 days and reduce the highest number of daily cases by 70% compared with a 30% contact tracing effectiveness. A similar trend was observed for symptomatic cases when a similar experiment setting was used. We also performed sensitivity analyses by using different combinations of contact tracing effectiveness and vaccination rates. In all scenarios, the effect of contact tracing on COVID-19 incidence persisted for both asymptomatic and symptomatic cases.ConclusionDespite testing only on two public health and social measures (PHSMs), we observed the scenario with low contact tracing and increasing vaccination rates successfully mimicked the current transmission trend in Malaysia. Hence, while vaccines are progressively rolled out, efficient contact tracing must be rapidly implemented concurrently to reach, find, test, isolate, and support the affected populations to bring the pandemic under control.

Author(s):  
Bernd Brüggenjürgen ◽  
Hans-Peter Stricker ◽  
Lilian Krist ◽  
Miriam Ortiz ◽  
Thomas Reinhold ◽  
...  

Abstract Aim To use a Delphi-panel-based assessment of the effectiveness of different non-pharmaceutical interventions (NPI) in order to retrospectively approximate and to prospectively predict the SARS-CoV-2 pandemic progression via a SEIR model (susceptible, exposed, infectious, removed). Methods We applied an evidence-educated Delphi-panel approach to elicit the impact of NPIs on the SARS-CoV-2 transmission rate R0 in Germany. Effectiveness was defined as the product of efficacy and compliance. A discrete, deterministic SEIR model with time step of 1 day, a latency period of 1.8 days, duration of infectiousness of 5 days, and a share of the total population of 15% assumed to be protected by immunity was developed in order to estimate the impact of selected NPI measures on the course of the pandemic. The model was populated with the Delphi-panel results and varied in sensitivity analyses. Results Efficacy and compliance estimates for the three most effective NPIs were as follows: test and isolate 49% (efficacy)/78% (compliance), keeping distance 42%/74%, personal protection masks (cloth masks or other face masks) 33%/79%. Applying all NPI effectiveness estimates to the SEIR model resulted in a valid replication of reported occurrence of the German SARS-CoV-2 pandemic. A combination of four NPIs at consented compliance rates might curb the CoViD-19 pandemic. Conclusion Employing an evidence-educated Delphi-panel approach can support SARS-CoV-2 modelling. Future curbing scenarios require a combination of NPIs. A Delphi-panel-based NPI assessment and modelling might support public health policy decision making by informing sequence and number of needed public health measures.


Author(s):  
Yi-Tui Chen

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.


2021 ◽  
Author(s):  
Yen-Chang Chen ◽  
Yen-Yuan Chen

UNSTRUCTURED While health care and public health workers are working on measures to mitigate the COVID-19 pandemic, there is an unprecedentedly large number of people spending much more time indoors, and relying heavily on the Internet as their lifeline. What has been overlooked is the influence of the increasing online activities on public health issues. In this article, we pointed out how a large-scale online activity called cyber manhunt may threaten to offset the efficacy of contact tracing investigation, a public health intervention considered highly effective in limiting further transmission in the early stage of a highly contagious disease outbreak such as the COVID-19 pandemic. In the first section, we presented a case to show how personal information obtained from contact investigation and disclosed in part on the media provoked a vehement cyber manhunt. We then discussed the possible reasons why netizens collaborate to reveal anonymized personal information about contact investigation, and specify, from the perspective of public health and public health ethics, four problems of cyber manhunt, including the lack of legitimate public health goals, the concerns about privacy breach, the impact of misinformation, and social inequality. Based on our analysis, we concluded that more moral weight may be given to protecting one's confidentiality, especially in an era with the rapid advance of digital and information technologies.


2021 ◽  
Author(s):  
Leighton M Watson

Aim: The August 2021 COVID-19 outbreak in Auckland has caused the New Zealand government to transition from an elimination strategy to suppression, which relies heavily on high vaccination rates in the population. As restrictions are eased and as COVID-19 leaks through the Auckland boundary, there is a need to understand how different levels of vaccination will impact the initial stages of COVID-19 outbreaks that are seeded around the country. Method: A stochastic branching process model is used to simulate the initial spread of a COVID-19 outbreak for different vaccination rates. Results: High vaccination rates are effective at minimizing the number of infections and hospitalizations. Increasing vaccination rates from 20% (approximate value at the start of the August 2021 outbreak) to 80% (approximate proposed target) of the total population can reduce the median number of infections that occur within the first four weeks of an outbreak from 1011 to 14 (25th and 75th quantiles of 545-1602 and 2-32 for V=20% and V=80%, respectively). As the vaccination rate increases, the number of breakthrough infections (infections in fully vaccinated individuals) and hospitalizations of vaccinated individuals increases. Unvaccinated individuals, however, are 3.3x more likely to be infected with COVID-19 and 25x more likely to be hospitalized. Conclusion: This work demonstrates the importance of vaccination in protecting individuals from COVID-19, preventing high caseloads, and minimizing the number of hospitalizations and hence limiting the pressure on the healthcare system.


2021 ◽  
Author(s):  
Santiago Romero-Brufau ◽  
Ayush Chopra ◽  
Alex J Ryu ◽  
Esma Gel ◽  
Ramesh Raskar ◽  
...  

AbstractObjectivesTo estimate population health outcomes under delayedsecond dose versus standard schedule SARS-CoV-2 mRNA vaccination.DesignAgent-based modeling on a simulated population of 100,000 based on a real-world US county. The simulation runs were replicated 10 times. To test the robustness of these findings, simulations were performed under different estimates for single-dose efficacy and vaccine administration rates, and under the possibility that a vaccine prevents only symptoms but not asymptomatic spread.Settingpopulation level simulation.Participants100,000 agents are included in the simulation, with a representative distribution of demographics and occupations. Networks of contacts are established to simulate potentially infectious interactions though occupation, household, and random interactionsInterventionswe simulate standard Covid-19 vaccination, versus delayed-second-dose vaccination prioritizing first dose. Sensitivity analyses include first-dose vaccine efficacy of 70%, 80% and 90% after day 12 post-vaccination; vaccination rate of 0.1%, 0.3%, and 1% of population per day; assuming the vaccine prevents only symptoms but not asymptomatic spread; and an alternative vaccination strategy that implements delayed-second-dose only for those under 65 years of age.Main outcome measurescumulative Covid-19 mortality over 180 days, cumulative infections and hospitalizations.ResultsOver all simulation replications, the median cumulative mortality per 100,000 for standard versus delayed second dose was 226 vs 179; 233 vs 207; and 235 vs 236; for 90%, 80% and 70% first-dose efficacy, respectively. The delayed-second-dose strategy was optimal for vaccine efficacies at or above 80%, and vaccination rates at or below 0.3% population per day, both under sterilizing and non-sterilizing vaccine assumptions, resulting in absolute cumulative mortality reductions between 26 and 47 per 100,000. The delayed-second-dose for those under 65 performed consistently well under all vaccination rates tested.ConclusionsA delayed-second-dose vaccination strategy, at least for those under 65, could result in reduced cumulative mortality under certain conditions.


2004 ◽  
Vol 25 (11) ◽  
pp. 918-922 ◽  
Author(s):  
Catherine Sartor ◽  
Herve Tissot-Dupont ◽  
Christine Zandotti ◽  
Francoise Martin ◽  
Pierre Roques ◽  
...  

AbstractObjective:Rates of annual influenza vaccination of healthcare workers (HCWs) remained low in our university hospital. This study was conducted to evaluate the impact of a mobile cart influenza vaccination program on HCW vaccination.Methods:From 2000 to 2002, the employee health service continued its annual influenza vaccination program and the mobile cart program was implemented throughout the institution. This program offered influenza vaccination to all employees directly on the units. Each employee completed a questionnaire. Vaccination rates were analyzed using the Mantel–Haenszel test.Results:The program proposed vaccination to 50% to 56% of the employees. Among the nonvaccinated employees, 52% to 53% agreed to be vaccinated. The compliance with vaccination varied from 61% to 77% among physicians and medical students and from 38% to 55% among nurses and other employees. Vaccination of the chief or associate professor of the unit was associated with a higher vaccination rate of the medical staff (P < .01). Altogether, the vaccination program led to an increase in influenza vaccination among employees from 6% in 1998 and 7% in 1999 before the mobile cart program to 32% in 2000, 35% in 2001, and 32% in 2002 (P < .001).Conclusions:The mobile cart program was associated with a significantly increased vaccination acceptance. Our study was able to identify HCW groups for which the mobile cart was effective and highlight the role of the unit head in its success.


2021 ◽  
Vol 66 (Special Issue) ◽  
pp. 156-157
Author(s):  
Petru Sandu ◽  
◽  
Maria Aluaș ◽  
Răzvan M. Cherecheș ◽  
◽  
...  

"Besides its undoubtable significant contribution to morbidity and mortality worldwide, the COVID-19 pandemic has had numerous political, social, economic, and public health implications. Vaccination, an already long debated public health ethics theme, has reoccurred in force, as the efforts of the scientific community to curb the pandemic resulted in a viable vaccine less than one year since COVID-19 was declared a pandemic. High-level, international negotiations dictated states’ COVID-19 vaccine availability in the first few months, therefore each national Government had to develop and deploy vaccination campaigns prioritizing certain population categories. This paper aims to present Romanian COVID-19 vaccination campaign, from its inception to the present days, by focusing on the ethical considerations (e.g. prioritization, coercion, non-discrimination) and their practical implications ( e.g. vaccination hesitancy, rates, fake news). Like most countries in the European Community, Romania has initially adopted a Rawlsian approach to vaccination, prioritizing the older adults and the individuals with chronic conditions. However, unlike other European countries, coercion was not considered in any form (e.g. extended mobility facilities for the vaccinated), more recently incentives such as food vouchers being discussed. The impact of these decisions on the vaccination rates and hesitancy are discussed in the context of other European countries examples of vaccination campaigns. "


Author(s):  
Michael B. A. Oldstone

This chapter highlights the story of autism, the widespread acceptance of its incorrect cause, and the impact on use of vaccines, all stemming directly from deliberate, false reporting. The basic conflict is twofold. First, involvement of a scientific method that must be reproducible, be reliable, and possess substantial proof is in conflict with common/personal beliefs. Second, doctors, scientists, and public health workers, despite their mandate to listen to parents and patients concerning their opinions, must base medical conclusions on evidence that validates the outcome of each patient’s health issue. It is in this milieu that autism and the anti-vaccine groups still do battle. In 1998, Lancet, a usually respectable and reputable English journal, published Dr. Andrew Wakefield’s opinion that the measles, mumps, rubella (German measles) vaccine injected into the arms of children caused inflammation, leading to harmful chemicals entering the bloodstream through the gut (intestine). These factors, he said, traveled to the brain, where the harmful chemicals/toxins caused autism. In the face of this “fake news” about the source of autism and measles, the vaccination rate for measles dropped in the United Kingdom and Ireland.


2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Lili Tao ◽  
Ming Lu ◽  
Xiaoning Wang ◽  
Xiaoyan Han ◽  
Shuming Li ◽  
...  

Abstract Background This study was conducted to evaluate the impact of a comprehensive community intervention on cognition and inoculation behaviors of diabetic patients immunized with influenza vaccine. Methods A total of 1538 diabetic patients aged 35 years and above for outpatient visits and follow-up treatments were selected from six community health service centers (three for the experimental group, and the other three for the control group) in Chaoyang District, Beijing. Comprehensive interventions applied to the experimental group include patient intervention and community climate interventions. We compared the total awareness of influenza vaccine knowledge and influenza vaccination rates between the two groups before and after the intervention. Results Before the intervention, the total awareness rate of influenza vaccine in the experimental group and the control group was similar (50.6 and 50.2%, respectively. P = 0.171). After the intervention, the awareness rate of influenza vaccine in the experimental group and the control group increased. The amplitude of the increase was similar (70.3 and 70.1%, respectively. P = 0.822,). Before the intervention, there was no significant difference in the influenza vaccination rate between the experimental group and the control group (29.0 and 26.8%, respectively. P = 0.334). After the intervention, the vaccination rate of the experimental group was higher than that of the control group. The difference was statistically significant (The vaccination rate 45.8 and 27.4% for the experimental group and the control group, respectively. P < 0.001). Conclusion Comprehensive community interventions had a positive effect on vaccination in diabetic patients. Trial registration ChiCTR1900025194, registered in Aug,16th, 2019. Retrospectively registered.


2021 ◽  
pp. 136787792199745
Author(s):  
Mark Andrejevic ◽  
Hugh Davies ◽  
Ruth DeSouza ◽  
Larissa Hjorth ◽  
Ingrid Richardson

In this article we explore preliminary findings from the study COVIDSafe and Beyond: Perceptions and Practices conducted in Australia in 2020. The study involved a survey followed by interviews, and aimed to capture the dynamic ways in which members of the Australian public perceive the impact of Covid practices – especially public health measures like the introduction of physical and social distancing, compulsory mask wearing, and contact tracing. In the rescripting of public space, different notions of formal and informal surveillance, along with different textures of mediated and social care, appeared. In this article, we explore perceptions around divergent forms of surveillance across social, technological, governmental modes, and the relationship of surveillance to care in our media and cultural practices. What does it mean to care for self and others during a pandemic? How does care get enacted in, and through, media interfaces and public interaction?


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