Is increased mortality by multiple exposures to COVID-19 an overseen factor when aiming for herd immunity?

Helle, Kristina Barbara; Sadiku, Arlinda; Zelleke, Girma Mesfin; Ibrahim, Toheeb B.; Bouba, Aliou; Obama, Henri Christian Junior Tsoungui; Appiah, Vincent; Ngwa, Gideon A.; Teboh-Ewungkem, Miranda I.; Schneider, Kristan A.

doi:10.1371/journal.pone.0253758

Cited by 9 publications

(7 citation statements)

References 42 publications

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“…However, attendance of MGEs, observing a person with a cough at MGEs, and contact with a COVID-19 patient were associated with complications, inferior recovery, and less frequent return to usual health. All of the above highlights the importance of intensity of COVID-19 exposure, duration, viral load, and the place where the exposure occurred [78][79][80][81]. In experimental models, the differences between the persistence of virus infection and the quantity of inoculum have been found [82].…”

Section: Discussionmentioning

confidence: 99%

Complications Post-COVID-19 and Risk Factors among Patients after Six Months of a SARS-CoV-2 Infection: A Population-Based Prospective Cohort Study

Domènech-Montoliu¹,

Puig-Barberà

Pac-Sa³

et al. 2022

Epidemiologia

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In October 2020, we conducted a population-based prospective cohort study to determine post-COVID-19 complications, recovery, return to usual health, and associated risk factors in 536 cases of COVID-19 outbreak in Borriana (Spain) by administering an epidemiological questionnaire via phone interviews. A total of 484 patients participated (90.3%), age mean 37.2 ± 17.1 years, and 301 females (62.2%). Mild illness was the most common COVID-19 manifestation. After six months, 160 patients (33.1%) suffered at least one complication post-COVID-19, and 47 (29.4%) of them sought medical assistance. The most frequent persistent symptoms were hair loss, fatigue, loss of smell or taste, and headache. Risk factors associated with a complication were female sex (adjusted relative risk, [aRR] = 1.93 95% confidence interval [CI] 1.41–2.65), age 35 years and above (aRR = 1.50 95% CI 1.14–1.99), B blood group (aRR = 1.51 95% CI 1.04–2.16), current smoker (RR = 1.61 95% CI 1.02–2.54), and at least a COVID-19 exposure (aRR = 2.13 95% CI 1.11–4.09). Male sex, age younger than 35 years, and low COVID-19 exposures were associated with better recovery and return to usual health. A third of patients presented persistent symptoms compatible with the long-COVID-19 syndrome. In conclusion, an active medical follow-up of post-COVID-19 patients must be implemented.

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Section: Discussionmentioning

confidence: 99%

Complications Post-COVID-19 and Risk Factors among Patients after Six Months of a SARS-CoV-2 Infection: A Population-Based Prospective Cohort Study

Domènech-Montoliu¹,

Puig-Barberà

Pac-Sa³

et al. 2022

Epidemiologia

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“…e.g. [72][73][74][75]). To overcome this problem, we introduced sub-stages of the model compartments (Erlang-stages), which result in Erlang-distributed durations, allowing to adjust their variance.…”

Section: Discussionmentioning

confidence: 99%

Predicting the combined effects of case isolation, safe funeral practices, and contact tracing during Ebola virus disease outbreaks

Bouba

Helle

Schneider

2022

Preprint

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Background: The recent outbreaks of Ebola virus disease (EVD) in Uganda and the Marburg virus disease in Ghana reflect a persisting threat of Filoviridae to the global health community. Characteristic of Filoviridae are not just their high case fatality rates, but also that corpses are highly contagious and prone to cause infections in the absence of appropriate precautions. Vaccines against the most virulent Ebolavirus species, the Zaire ebolavirus (ZEBOV) are approved. However, there exists no approved vaccine or treatment against the Sudan ebolavirus (SUDV) which causes the current outbreak of EVD. Hence, the control of the outbreak relies on case isolation, safe funeral practices, and contact tracing. So far, the effectiveness of these control measures was studied only separately by epidemiological models, while the impact of their interaction is unclear. Methods and findings: To sustain decision making in public health-emergency management, we introduce a predictive model to study the interaction of case isolation, safe funeral practices, and contact tracing. The model is a complex extension of an SEIR-type model, and serves as an epidemic preparedness tool. The model considers different phases of the EVD infections, the possibility of infections being treated in isolation (if appropriately diagnosed), in hospital (if not properly diagnosed), or at home (if the infected do not present to hospital for whatever reason). It is assumed that the corpses of those who died in isolation are buried with proper safety measures, while those who die outside isolation might be buried unsafely, such that transmission can occur during the funeral. Furthermore, the contacts of individuals in isolation will be traced. Based on parameter estimates from the scientific literature, the model suggests that proper diagnosis and hence isolation of cases has the highest impact in reducing the size of the outbreak. However, the combination of case isolation and safe funeral practices alone are insufficient to fully contain the epidemic under plausible parameters. This changes if these measures are combined with contact tracing. In addition, shortening the time to successfully trace back contacts contribute substantially to contain the outbreak. Conclusions: In the absence of an approved vaccine and treatment, EVD management by proper and fast diagnostics in combination with epidemic awareness are fundamental. Awareness will particularly facilitate contact tracing and safe funeral practices. Moreover, proper and fast diagnostics are a major determinant of case isolation. The model introduced here is not just applicable to EVD, but also to other hemorrhagic diseases such as the MVD or the Lassa fever.

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“…As a consequence the waiting times to progress between compartments are Erlang-distributed (cf. [32][33][34][35]).…”

Section: Course Of the Diseasementioning

confidence: 99%

Predicting the impact of COVID-19 vaccination campaigns – a flexible age-dependent, spatially-stratified predictive model, accounting for multiple viral variants and vaccines

Schneider

Obama

Yousif

et al. 2022

Preprint

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Background: After COVID-19 vaccines received approval, vaccination campaigns were launched worldwide. Initially, these were characterized by a shortage of vaccine supply, and specific risk groups were prioritized. Once supply was guaranteed and vaccination coverage saturated, the focus shifted from risk groups to anti-vaxxers, the underaged population, and regions of low coverage. At the same time, hopes to reach herd immunity by vaccination campaigns were put into perspective by the emergence and spread of more contagious and aggressive viral variants. Particularly, concerns were raised that not all vaccines protect against the new-emerging variants. Methods and findings: A model designed to predict the effect of vaccination campaigns on the spread of viral variants is introduced. The model is a comprehensive extension of the model underlying the pandemic preparedness tool CovidSim 2.0 (http://covidsim.eu/). The model is age and spatially stratified, incorporates a finite (but arbitrary) number of different viral variants, and incorporates different vaccine products. The vaccines are allowed to differ in their vaccination schedule, vaccination rates, the onset of vaccination campaigns, and their effectiveness. These factors are also age and/or location dependent. Moreover, the effectiveness and the immunizing effect of vaccines are assumed to depend on the interaction of a given vaccine and viral variant. Importantly, vaccines are not assumed to immunize perfectly. Individuals can be immunized completely, only partially, or fail to be immunized against one or many viral variants. Not all individuals in the population are vaccinable. The model is formulated as a high-dimensional system of differential equations, which is implemented efficiently in the programming language Julia. As an example, the model was parameterized to reflect the epidemic situation in Germany until November 2021 and predicted the future dynamics of the epidemic under different interventions. In particular, without tightening contact reductions, a strong epidemic wave is predicted. At the current state, mandatory vaccination would be too late to have a strong effect on reducing the number of infections. However, it would reduce mortality. An emergency brake, i.e., an incidence-based stepwise lockdown would be efficient to reduce the number of infections and mortality. Furthermore, to specifically account for mobility between regions, the model was applied to two German provinces of particular interest: Saxony, which currently has the lowest vaccine rollout in Germany and high incidence, and Schleswig-Holstein, which has high vaccine rollout and low incidence. Conclusions: A highly sophisticated and flexible but easy-to-parameterize model for the ongoing COVID-19 pandemic is introduced. The model is capable of providing useful predictions for the COVID-19 pandemic, and hence provides a relevant tool for epidemic decision-making. The model can be adjusted to any country, to derive the demand for hospital and ICU capacities as well as economic collateral damages.

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Is increased mortality by multiple exposures to COVID-19 an overseen factor when aiming for herd immunity?

Cited by 9 publications

References 42 publications

Complications Post-COVID-19 and Risk Factors among Patients after Six Months of a SARS-CoV-2 Infection: A Population-Based Prospective Cohort Study

Complications Post-COVID-19 and Risk Factors among Patients after Six Months of a SARS-CoV-2 Infection: A Population-Based Prospective Cohort Study

Predicting the combined effects of case isolation, safe funeral practices, and contact tracing during Ebola virus disease outbreaks

Predicting the impact of COVID-19 vaccination campaigns – a flexible age-dependent, spatially-stratified predictive model, accounting for multiple viral variants and vaccines

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