Impact of waning immunity against SARS-CoV-2 severity exacerbated by vaccine hesitancy.

Publication date: Aug 01, 2024

The SARS-CoV-2 pandemic has generated a considerable number of infections and associated morbidity and mortality across the world. Recovery from these infections, combined with the onset of large-scale vaccination, have led to rapidly-changing population-level immunological landscapes. In turn, these complexities have highlighted a number of important unknowns related to the breadth and strength of immunity following recovery or vaccination. Using simple mathematical models, we investigate the medium-term impacts of waning immunity against severe disease on immuno-epidemiological dynamics. We find that uncertainties in the duration of severity-blocking immunity (imparted by either infection or vaccination) can lead to a large range of medium-term population-level outcomes (i. e. infection characteristics and immune landscapes). Furthermore, we show that epidemiological dynamics are sensitive to the strength and duration of underlying host immune responses; this implies that determining infection levels from hospitalizations requires accurate estimates of these immune parameters. More durable vaccines both reduce these uncertainties and alleviate the burden of SARS-CoV-2 in pessimistic outcomes. However, heterogeneity in vaccine uptake drastically changes immune landscapes toward larger fractions of individuals with waned severity-blocking immunity. In particular, if hesitancy is substantial, more robust vaccines have almost no effects on population-level immuno-epidemiology, even if vaccination rates are compensatorily high among vaccine-adopters. This pessimistic scenario for vaccination heterogeneity arises because those few individuals that are vaccine-adopters are so readily re-vaccinated that the duration of vaccinal immunity has no appreciable consequences on their immune status. Furthermore, we find that this effect is heightened if vaccine-hesitants have increased transmissibility (e. g. due to riskier behavior). Overall, our results illustrate the necessity to characterize both transmission-blocking and severity-blocking immune time scales. Our findings also underline the importance of developing robust next-generation vaccines with equitable mass vaccine deployment.

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Concepts Keywords
Mathematical Computational Biology
Models COVID-19
Pessimistic COVID-19 Vaccines
Rapidly COVID-19 Vaccines
Vaccines Humans
Pandemics
SARS-CoV-2
Vaccination
Vaccination Hesitancy

Semantics

Type Source Name
disease VO vaccine
disease MESH infections
disease MESH morbidity
disease VO vaccination
disease VO population
disease IDO infection
disease IDO host
disease VO vaccinated
disease VO time
disease VO Canada
disease MESH emergency
drug DRUGBANK Cysteamine
disease VO effective
disease IDO susceptibility
disease MESH breakthrough infection
drug DRUGBANK Ilex paraguariensis leaf
disease IDO pathogen
disease VO dose
disease MESH COVID 19
disease MESH secondary infections
disease MESH death
disease VO vaccination coverage
disease VO Optaflu
disease IDO intervention
drug DRUGBANK Aspartame
disease IDO primary infection
disease MESH reinfection
disease VO transmission blocking vaccine
drug DRUGBANK Coenzyme M
disease MESH Long COVID
disease MESH Infectious diseases
disease IDO history
disease IDO symptom
disease MESH chronic disease
disease IDO infectious disease
disease VO report

Original Article

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