A conceptual model for optimizing vaccine coverage to reduce vector-borne infections in the presence of antibody-dependent enhancement

Abstract

BackgroundMany vector-borne diseases co-circulate, as the viruses from the same family are also transmitted by the same vector species. For example, Zika and dengue viruses belong to the same Flavivirus family and are primarily transmitted by a common mosquito species Aedes aegypti. Zika outbreaks have also commonly occurred in dengue-endemic areas, and co-circulation and co-infection of both viruses have been reported. As recent immunological cross-reactivity studies have confirmed that convalescent plasma following dengue infection can enhance Zika infection, and as global efforts of developing dengue and Zika vaccines are intensified, it is important to examine whether and how vaccination against one disease in a large population may affect infection dynamics of another disease due to antibody-dependent enhancement.MethodsThrough a conceptual co-infection dynamics model parametrized by reported dengue and Zika epidemic and immunological cross-reactivity characteristics, we evaluate impact of a hypothetical dengue vaccination program on Zika infection dynamics in a single season when only one particular dengue serotype is involved.ResultsWe show that an appropriately designed and optimized dengue vaccination program can not only help control the dengue spread but also, counter-intuitively, reduce Zika infections. We identify optimal dengue vaccination coverages for controlling dengue and simultaneously reducing Zika infections, as well as the critical coverages exceeding which dengue vaccination will increase Zika infections.ConclusionThis study based on a conceptual model shows the promise of an integrative vector-borne disease control strategy involving optimal vaccination programs, in regions where different viruses or different serotypes of the same virus co-circulate, and convalescent plasma following infection from one virus (serotype) can enhance infection against another virus (serotype). The conceptual model provides a first step towards well-designed regional and global vector-borne disease immunization programs.

The age distribution of mortality from novel coronavirus disease (COVID-19) suggests no large difference of susceptibility by age

“…From the modelling perspective on mortality by Covid-19, age-dependency of severity should be carefully taken into consideration. In particular, in the mathematical models of ADE, previous models employed three types of assumptions 41 , the assumption of: increasing susceptibility to infection 42,43 , increasing transmissibility once infection occurred 42,44,45 , and increasing severity and/or mortality associated with infection 46 . Based on our results and from the biological/epidemiological observations of past SARS and MERS cases, the "increasing severity" assumption should be taken into account when analyzing SARS Cov-2 epidemics.…”

Modelling the impact of antibody-dependent enhancement on disease severity of Zika virus and dengue virus sequential and co-infection

“…By extending the model in [21], Billings et al were able to conduct some computational analyses to suggest optimal vaccination strategies [23]. Also, a modelling study reported that a dengue vaccine used in a population may increase ZIKV outbreaks under certain conditions owing to ADE [24]; however, the work [25] also showed that an appropriately designed and optimized dengue vaccination programme can not only help control the dengue spread but also reduce ZIKV infections. On the other hand, several withinhost mathematical models were proposed and used to quantitatively analyse [26][27][28] or theoretically investigate [29][30][31] the impact of ADE on the viral dynamics of primary and secondary infection of different dengue serotypes.…”

Does susceptibility to novel coronavirus (COVID-19) infection differ by age?: Insights from mathematical modelling

“…From the modelling perspective on mortality by Covid-19, age-dependency of severity should be carefully taken into consideration. In particular, in the mathematical models of ADE, the previous models employed three types of assumptions (Woodall and Adams, 2014), the assumption of: increasing susceptibility to infection (Recker et al, 2009; Tang et al, 2018), increasing transmissibility once infection occurred (Ferguson et al, 1999; Ferguson and Andreasen, 2002; Recker et al, 2009), and increasing severity and/or mortality associated with infection (Kawaguchi et al, 2003). Based on our results and from the biological/epidemiological observations of past SARS and MERS cases, the “increasing severity” assumption should be taken into account when analyzing SARS Cov-2 epidemics.…”