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Cochrane COVID-19 Study Register
Study record
Helle 2020First Published: 2021 Jul 21Updated Date: 2021 Jul 21

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

  1. Study Type
  2. Modelling
  1. Study Aim
  2. Transmission
  3. Epidemiology
  4. Prevention
  1. Study Design
  2. Other
  1. Intervention Assignment
  2. Not Applicable
Reference record

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

Helle KB, Sadiku A, Zelleke GM, Ibrahim TB, Bouba A, Tsoungui Obama HC, Appiah V, Ngwa GA, Teboh-Ewungkem MI, Schneider KA
Journal article
Report Results
BACKGROUND: Governments across the globe responded with different strategies to the COVID-19 pandemic. While some countries adopted measures, which have been perceived controversial, others pursued a strategy aiming for herd immunity. The latter is even more controversial and has been called unethical by the WHO Director-General. Inevitably, without proper control measures, viral diversity increases and multiple infectious exposures become common, when the pandemic reaches its maximum. This harbors not only a potential threat overseen by simplified theoretical arguments in support of herd immunity, but also deserves attention when assessing response measures to increasing numbers of infection. METHODS AND FINDINGS: We extend the simulation model underlying the pandemic preparedness web interface CovidSim 1.1 (http://covidsim.eu/) to study the hypothetical effect of increased morbidity and mortality due to 'multi-infections', either acquired at by successive infective contacts during the course of one infection or by a single infective contact with a multi-infected individual. The simulations are adjusted to reflect roughly the situation in the USA. We assume a phase of general contact reduction ("lockdown") at the beginning of the epidemic and additional case-isolation measures. We study the hypothetical effects of varying enhancements in morbidity and mortality, different likelihoods of multi-infected individuals to spread multi-infections and different susceptibility to multi-infections in different disease phases. It is demonstrated that multi-infections lead to a slight reduction in the number of infections, as these are more likely to get isolated due to their higher morbidity. However, the latter substantially increases the number of deaths. Furthermore, simulations indicate that a potential second lockdown can substantially decrease the epidemic peak, the number of multi-infections and deaths. CONCLUSIONS: Enhanced morbidity and mortality due to multiple disease exposure is a potential threat in the COVID-19 pandemic that deserves more attention. Particularly it underlines another facet questioning disease management strategies aiming for herd immunity
Reference record

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

Helle KB, Sadiku A, Zelleke GM, Bouba A, Ibrahim TB, Tsoungui Obama HCJ, Appiah V, Ngwa GA, Teboh-Ewungkem MI, Schneider KA
Unpublished article (preprint)
Report Results
Background: Governments across the globe responded with different strategies to the COVID-19 pandemic. While some countries adapted draconic measures, which have been perceived controversial others pursued a strategy aiming for herd immunity. The latter is even more controversial and has been called unethical by the WHO Director-General. Inevitably, without proper control measure, viral diversity increases and multiple infectious exposures become common, when the pandemic reaches its maximum. This harbors not only a potential threat overseen by simplified theoretical arguments in support of herd immunity, but also deserves attention when assessingresponse measures to increasing numbers of infection. Methods and findings: We extend the simulation model underlying the pandemic preparedness web interface CovidSim 1.1 (http://covidsim.eu/) to study the hypothetical effect of increased morbidity and mortality due to 'multi infections', either acquired at by successive infective contacts during the course of one infection or by a single infective contact with a multi-infected individual. The simulations are adjusted to reflect roughly the situation in the East Coast of the USA. We assume a phase of general contact reduction ('lockdown') at the beginning of the epidemic and additional case-isolation measures. We study the hypothetical effects of varying enhancements in morbidity and mortality, different likelihoods of multi-infected individuals to spread multi infections and different susceptibility to multi infectious in different disease phases. It is demonstrated that multi infections lead to a slight reduction in the number of infections, as these are more likely to get isolated due to their higher morbidity. However, the latter substantially increases the number of deaths. Furthermore, simulations indicate that a potential second lockdown can substantially decrease the epidemic peak, the number of multi-infections and deaths. Conclusions: Enhanced morbidity and mortality due to multiple disease exposure is a potential threat in the COVID-19 pandemic that deserves more attention. Particularly it underlines another facet questioning disease management strategies aiming for herd immunityCompeting Interest StatementThe authors have declared no competing interest.Funding StatementK. A. S. could not have put together the research team without the supported by the German Academic Exchange (DAAD; https://www.daad.de/de/; Project-ID 57417782), the Saechsisches Staatsministerium fur Wissenschaft, Kultur und Tourismus and Saechsische Aufbaubank - Foerderbank (SMWK-SAB; https://www.smwk.sachsen.de/; https://www.sab.sachsen.de/; project "Innovationsvorhaben zur Profilschaerfung an Hochschulen fuer angewandte Wissenschaften", Project-ID 100257255), the Federal Ministry of Education and Research (BMBF) and the DLR (Project-ID 01DQ20002; https://www.bmbf.de/; https://www.dlr.de/). G. N. is supported by the German Academic Exchange (DAAD; https://www.daad.de/de/; Project-ID 57479556) to K.A.S. K.B.H. was supported by the ESF-SMWK-SAB (ESF-SMWK-SAB, https://www.esf.de/portal/DE/Startseite/inhalt.html, https://www.strukturfonds.sachsen.de/europaeischer-sozialfonds-esf.html, https://www.smwk.sachsen.de/, https://www.sab.sachsen.de/; "Nachwuchsforschergruppe - Agile Publika"; Project 100310497) A.S. is supported by a scholarship from the ESF-SMWK-SAB ESF-SMWK-SAB, https://www.esf.de/portal/DE/Startseite/inhalt.html, https://www.strukturfonds.sachsen.de/europaeischer-sozialfonds-esf.html, https://www.smwk.sachsen.de/, https://www.sab.sachsen.de/; Project 1562608885160). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Author DeclarationsI confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.YesThe details of the IRB/oversight body that provided approval or exemption for the research described are given below:NA - the type of research does not equire RIB approval.All necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived.YesI understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance).Yes I have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable.YesSimulated data is used. The source code will be made available upon publication