Super-Spreaders Out, Super-Spreading In: The Effects of Infectiousness Heterogeneity and Lockdowns on Herd Immunity

Mapping Intimacies ◽

10.1101/2021.01.23.21250242 ◽

2021 ◽

Author(s):

Jhonatan Tavori ◽

Hanoch Levy

Keyword(s):

Infectious Diseases ◽

Preliminary Data ◽

Herd Immunity ◽

Personal Trait ◽

Two Factors ◽

Event Based ◽

S Model ◽

Reproduction Factor ◽

Operational Aspects

AbstractRecently, [8] has proposed that heterogeneity of infectiousness (and susceptibility) across individuals in infectious diseases, plays a major role in affecting the Herd Immunity Thresh-old (HIT). Such heterogeneity has been observed in COVID-19 and is recognized as overdis-persion (or “super-spreading”). The model of [8] suggests that super-spreaders contribute significantly to the effective reproduction factor, R, and that they are likely to get infected and immune early in the process. Consequently, under R0 ≈ 3 (attributed to COVID-19), the Herd Immunity Threshold (HIT) is as low as 5%, in contrast to 67% according to the traditional models [1, 2, 4, 10].This work follows up on [8] and proposes that heterogeneity of infectiousness (susceptibility) has two “faces” whose mix affects dramatically the HIT: (1) Personal-Trait-, and (2) Event-Based-Infectiousness (Susceptibility). The former is a personal trait of specific individuals (super-spreaders) and is nullified once those individuals are immune (as in [8]). The latter is event-based (e.g cultural super-spreading events) and remains effective throughout the process, even after the super-spreaders immune. We extend [8]’s model to account for these two factors, analyze it and conclude that the HIT is very sensitive to the mix between (1) and (2), and under R0 ≈ 3 it can vary between 5% and 67%. Preliminary data from COVID-19 suggests that herd immunity is not reached at 5%.We address operational aspects and analyze the effects of lockdown strategies on the spread of a disease. We find that herd immunity (and HIT) is very sensitive to the lock-down type. While some lockdowns affect positively the disease blocking and increase herd immunity, others have adverse effects and reduce the herd immunity.

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Adverse effects of the herd immunity or when childhood vaccination becomes deleterious for the epidemiology of infectious diseases in adults

Gériatrie et Psychologie Neuropsychiatrie du Viellissement ◽

10.1684/pnv.2011.0260 ◽

2011 ◽

Vol 9 (1) ◽

pp. 11-19

Author(s):

PIERRE-OLIVIER LANG

Keyword(s):

Adverse Effects ◽

Infectious Diseases ◽

Herd Immunity ◽

Childhood Vaccination

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Political Disagreement, Arrogance, and the Pursuit of Truth

Political Epistemology ◽

10.1093/oso/9780192893338.003.0014 ◽

2021 ◽

pp. 244-258

Author(s):

Michael P. Lynch

Keyword(s):

Infectious Diseases ◽

People Of Color ◽

Contributing Factors ◽

Political Disagreement ◽

Two Factors

This chapter explores two contributing factors to cognitive polarization. The first is what is known as epistemic disagreement—or disagreement over what is known, who knows it, or how we know. Crucially, even the perception that such disagreement is widespread—whether or not it actually is—can be dangerous. The second factor is intellectual arrogance. This is arrogance about what we know or think we know; it is the kind of arrogance that tells whites they have nothing to learn about racism from people of color and that reassures those who believe they know more about infectious diseases than those who spend their lives studying them. The chapter also attempts to argue that these two factors can be mutually reinforcing. This makes them doubly dangerous, because by increasing cognitive polarization, they in turn undermine the democratic value of the pursuit of truth.

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Current trends in paediatric infections in the Russian Federation

Kuban Scientific Medical Bulletin ◽

10.25207/1608-6228-2020-27-4-119-133 ◽

2020 ◽

Vol 27 (4) ◽

pp. 119-133

Author(s):

Yu. V. Lobzin ◽

S. V. Rychkova ◽

A. N. Uskov ◽

N. V. Skripchenko ◽

V. V. Fedorov

Keyword(s):

Infectious Diseases ◽

Russian Federation ◽

Herd Immunity ◽

Human Microbiome ◽

Economic Damage ◽

Comparative Dynamics ◽

Treatment And Prevention ◽

Intestinal Infections ◽

Acute Respiratory Diseases ◽

The Russian Federation

The onset of 2020 clearly demonstrated that infection agents pose a major threat to mankind. Current infectiology is shaped by resurrection of “old” seemingly forgotten infections, emergence of “new” infection agents, unusual combinations of known agents, evolving resistance of microorganisms to antibacterial drugs, transformation of human microbiome leading to distortions in herd immunity and, ultimately, emergence of healthcare-related infectious diseases, not letting alone threats of bioterror. Infection agents evolve together with mankind. Novel facets emerge in infectiology, alongside with trends in diagnosis, treatment and prevention of infectious diseases that become more diverse as the list of pathogens grows. Human and infection agent links extend beyond antagonistic relations towards symbiosis. Microorganisms adapt quickly in the new technogenic environment giving rise to novel pathogens and making it unlikely for the mankind to get free from infections any time soon.The total economic damage from infectious diseases increases by year, despite continuous improvement in therapy. Infectious mortality in children aged 0 to 14 years is the top fourth among other causes of death. The work assesses comparative dynamics of “common” childhood infections in the Russian Federation during 2018–2020. We analyse ofﬁcial statistics on paediatric infectious morbidity, comparative dynamics of main infectious diseases (acute respiratory diseases, intestinal infections of bacterial and viral nature, neuroinfections, anthropozoonotic infections, viral hepatitises), assess trends in morbidity of vaccine-preventable infections in children and adults in the Russian Federation, with greater detail towards selected regions, from January 2018 to April 2020.

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Pandemic governance: using event- based surveillance to manage emerging infectious diseases

The Surveillance-Industrial Complex ◽

10.4324/9780203094426-12 ◽

2013 ◽

pp. 58-74

Keyword(s):

Infectious Diseases ◽

Emerging Infectious Diseases ◽

Event Based

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Modelling infectious diseases with herd immunity in a randomly mixed population

10.21203/rs.3.rs-289776/v7 ◽

2021 ◽

Author(s):

Kian Boon Law ◽

Kalaiarasu M. Peariasamy ◽

Hishamshah Mohd. Ibrahim ◽

Noor Hisham Abdullah

Keyword(s):

Infectious Disease ◽

Infectious Diseases ◽

Transmission Rate ◽

Herd Immunity ◽

Sir Model ◽

Mixed Population ◽

Transmission Dynamics ◽

Transmission Model ◽

Infection Model ◽

Vaccination Rates

Abstract Background The conventional susceptible-infectious-recovered (SIR) model tends to overestimate the transmission dynamics of infectious diseases and ends up with total infections and total immunized population exceeding the threshold required for control and eradication of infectious diseases. The study aims to overcome the limitation by allowing the transmission rate of infectious disease to decline along with the reducing risk of contact infection. Methods Two new SIR models were developed to mimic the declining transmission rate of infectious diseases at different stages of transmission. Model A mimicked the declining transmission rate along with the reducing risk of transmission following infection, while Model B mimicked the declining transmission rate following recovery. Then, the conventional SIR model, Model A and Model B were used to simulate an infectious disease with a basic reproduction number (r0) of 3.0 and a herd immunity threshold (HIT) of 0.667 with and without vaccination. The infectious disease was expected to be controlled or eradicated when the total immunized population either through infection or vaccination reached the level predicted by the HIT. Outcomes of simulations were assessed at the time when the total immunized population reached the level predicted by the HIT, and at the end of simulations. Findings All three models performed likewise at the beginning of the transmission when sizes of infectious and recovered were relatively small as compared with the population size. The infectious disease modelled using the conventional SIR model appeared completely out of control even when the HIT was achieved in all scenarios with and without vaccination. The infectious disease modelled using Model A appeared to be controlled at the level predicted by the HIT in all scenarios with and without vaccination. Model B projected the infectious disease to be controlled at the level predicted by the HIT only at high vaccination rates. At lower vaccination rates or without vaccination, the level at which the infectious disease was controlled cannot be accurately predicted by the HIT. Conclusion Transmission dynamics of infectious diseases with herd immunity can accurately be modelled by allowing the transmission rate of infectious disease to decline along with the combined risk of contact infection. Model B provides a more credible framework for modelling infectious diseases with herd immunity in a randomly mixed population.

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The risk for a new COVID-19 wave – and how it depends on R0, the current immunity level and current restrictions

10.1101/2020.10.09.20209981 ◽

2020 ◽

Author(s):

Tom Britton ◽

Pieter Trapman ◽

Frank Ball

Keyword(s):

Preventive Measures ◽

Reproduction Number ◽

Social Activity ◽

Herd Immunity ◽

Time Varying ◽

The World ◽

Two Factors ◽

Second Wave ◽

Different Parts ◽

Future Outbreak

AbstractThe COVID-19 pandemic has hit different parts of the world differently: some regions are still in the rise of the first wave, other regions are now facing a decline after a first wave, and yet other regions have started to see a second wave. The current immunity level î in a region is closely related to the cumulative fraction infected, which primarily depends on two factors: a) the initial potential for COVID-19 in the region (often quantified by the basic reproduction number R0), and b) the timing, amount and effectiveness of preventive measures put in place. By means of a mathematical model including heterogeneities owing to age, social activity and susceptibility, and allowing for time-varying preventive measures, the risk for a new epidemic wave and its doubling time, and how they depend on R0, î and the overall effect of the current preventive measures, are investigated. Focus lies on quantifying the minimal overall effect of preventive measures pMin needed to prevent a future outbreak. The first result shows that the current immunity level î plays a more influential roll than when immunity is obtained from vaccination. Secondly, by comparing regions with different R0 and î it is shown that regions with lower R0 and low î may now need higher preventive measures (pMin) compared with other regions having higher R0 but also higher î, even when such immunity levels are far from herd immunity.

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STATUS GIZI ANAK USIA 24 - 59 BULAN (Studi Analitik Di Puskesmas Wangi-Wangi Selatan Kabupaten Wakatobi)

Jurnal Publikasi Kesehatan Masyarakat Indonesia ◽

10.20527/jpkmi.v6i2.7453 ◽

2019 ◽

Vol 6 (2) ◽

Author(s):

Yuyun Firdawati ◽

Arlin Adam ◽

Andi Alim

Keyword(s):

Infectious Diseases ◽

Nutritional Status ◽

Health Center ◽

Quantitative Research ◽

Family Income ◽

Maternal Knowledge ◽

The South ◽

Two Factors ◽

Nutritional Status Of Children ◽

Relationship Of

Masalah gizi di Indonesia, sebagai mana halnya dengan negara-negara berkembang lainnya pada anak sangat dipengaruhi oleh dua faktor yaitu asupan makanan dan penyakit infeksi. Faktor konsumsi makanan merupakan penyebab langsung dari kejadian gizi buruk pada balita.Tujuan penelitian ini adalah untuk mengetahui hubungan asupan gizi, pengetahuan ibu tentang gizi, penyakit infeksi, dan pendapatan keluarga dengan status gizi anak usia 24 – 59 bulan di Puskesmas Wangi-Wangi Selatan Kabupaten Wakatobi. Penelitian ini dilakukan di Puskesmas Wangi-Wangi Selatan Kabupaten Wakatobi dengan metode penelitian kuantitatif dengan pendekatan analitik pada 72 responden yang memenuhi kriteria yang dilaksanakan melalui wawancara dengan menggunakan kuesioner sebagai acuan pertanyaan. Hasil penelitian menujukan bahwa ada hubungan antara asupan gizi, penyakit infeksi, pengetahuan ibu dan pendapatan keluarga dengan status gizi anak usia 24 – 59 bulan di Puskesmas Wangi-Wangi Selatan Kabupaten Wakatobi dengan nilai p = 0,000. Disarankan kepada petugas Puskesmas agar perlu dilakukan upaya perbaikan gizi pada anak balita, melalui penyuluhan mengenai pentingnya asupan zat gizi kepada anak balita, dan memberitahukan kepada ibu pentingnya rutin ke puskesmas.Kata-kata kunci: Status gizi, asupan gizi, pengetahuan ibu, penyakit infeksi, pendapatan keluargaABSTRACTNutritional problems in Indonesia, as well as other developing countries in children are strongly influenced by two factors, namely food supply and infectious diseases. Food consumption factor is a direct cause of the incidence of malnutrition in infants. The purpose of this research is to know the relationship of nutritional supplay, knowledge of mothers about nutrition, infectious diseases, and family income with the nutritional status of children aged 24 – 59 months at the South Wangi-Wangi health center District of Wakatobi. This research was conducted in South Wangi-Wangi health center in Wakatobi District with quantitative research method with analytical approach in 72 respondents who meet the criteria implemented through interviews using questionnaires as Reference questions. The results showed that there was a relationship between nutritional intake, infectious diseases, mother knowledge and family income with nutritional status of children aged 24 – 59 months at the South Wangi-Wangi Health center of Wakatobi regency with a value P = 0.000. It is recommended to the health center officers to be done efforts to improve nutrition in children, because there are still many children who have a lack of energy intake and protein, by increasing the awareness of toddler mothers through About the importance of nutrient supply to children, and inform the mother of the importance of routine to the health center.Keywords: nutritional Status, nutritional supplay, maternal knowledge, infectious diseases, family income

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‘If your child’s vaccinated, why do you care about mine?’ Rhetoric, responsibility, power and vaccine rejection

Journal of Sociology ◽

10.1177/1440783319893468 ◽

2019 ◽

pp. 144078331989346 ◽

Cited By ~ 1

Author(s):

Katie Attwell ◽

David T. Smith ◽

Paul R. Ward

Keyword(s):

Social Responsibility ◽

Infectious Diseases ◽

Herd Immunity ◽

The Social ◽

Community Protection

The social responsibility logic underpinning vaccination is omnipresent in the rhetoric surrounding its acceptance and rejection. People who reject vaccination are constantly faced with arguments from the vaccinating mainstream to which they must respond. Understanding the conceptual world of vaccine rejection requires us to understand how vaccine sceptics construct answers to complaints that their choices endanger other people. This article analyses interviews with 29 vaccine-sceptical parents who are presented with claims that their choices are not just morally wrong, but dangerous to others. We argue that vaccine rejecters possess power because their decisions can result in the transmission of infectious diseases through their communities. However, they refuse to acknowledge this power because, through a variety of rationalisations, they do not accept the logic of community protection (herd immunity) and social responsibility. Strategies to prompt parents’ consideration of others can include breaking out of the ontologically individualistic framing of the disagreement.

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