Vaccination strategies for minimizing loss of life in Covid-19 in a Europe lacking vaccines

Abstract

BackgroundWe aimed at identifying vaccination strategies that minimize loss of life in the Covid-19 pandemic. Covid-19 mainly kills the elderly, but the pandemic is driven by social contacts that are more frequent in the young. Vaccines elicit stronger immune responses per dose in younger persons. As vaccine production is a bottleneck, many countries have adopted a strategy of first vaccinating the elderly and vulnerable, while postponing vaccination of the young.MethodsBased on published age-stratified immunogenicity data of the Moderna mRNA-1273 vaccine, we compared the established “one dose fits all” approach with tailored strategies: The known differential immunogenicity of vaccine doses in different age groups is exploited to vaccinate the elderly at full dose, while the young receive a reduced dose, amplifying the number of individuals receiving the vaccine early. A modeling approach at European Union scale with population structure, Covid-19 case and death rates similar to Europe in late January 2021 is used.ResultsWhen the elderly were vaccinated preferentially, the pandemic initially continued essentially unchecked, as it was dominantly driven by social contacts in other age groups. Tailored strategies, including regular dosing in the elderly but reduced dose vaccination in the young, multiplied early vaccination counts, and even with some loss in protection degree for the individual person, the protective effect towards stopping the pandemic and protecting lives was enhanced, even for the elderly.ConclusionProtecting the vulnerable, minimizing overall deaths and stopping the pandemic is best achieved by an adaptive vaccination strategy using an age-tailored vaccine dose.

Population-level implications of the Israeli booster campaign to curtail COVID-19 resurgence

“…However, it is far less effective, with respect to all outcomes, than boosting wider segments of the population. In the case of limited vaccine supply, these results support the consideration of vaccination strategies involving partial doses designed to extend vaccine coverage (15,16). We further show that, when the epidemic is exponentially growing, the success of the booster campaign is sensitive to the timing of the initiation.…”

Assessing Age-Specific Vaccination Strategies and Post-vaccination Reopening Policies for COVID-19 Control Using SEIR Modeling Approach

“…S1) data in order to optimize the age-specific vaccination strategy for different countries. Compared with the previous literature (Bubar et al 2020 ; Matrajt et al 2020 ; Jentsch et al 2021 ; Hunziker 2021 ), we used a continuous function, Beta distribution, to approximate the age-specific vaccination distribution, so that we could conveniently optimize the age distribution by minimizing the three endpoints with respect to the Beta distribution parameters ( and ).…”

“…Actually this indicates that the age distribution is optimized toward the maximum or minimum of the age. Another endpoint, “years of life lost (YLL),” was also used to evaluate the effectiveness of vaccination strategies (Bubar et al 2020 ; Hunziker 2021 ), which may result in shifting the vaccination priority to younger people. The proposed age-specific SEIR model contains many parameters, which are not identifiable based on the observed epidemic data only (daily cases and/or deaths).…”

The Politics of Vaccines—How to Determine a Fair Vaccine Allocation: Hierarchy, Negotiations, or Culture?

“…Thereafter, each age group, in descending order, became eligible for vaccination until all those over 18 years had been vaccinated. These allocation priorities were the same as those used by most other European countries (Hunziker, 2021); the only difference was that vaccination of health personnel became the next priority after protecting the most vulnerable groups (Sølhusvik, 2021). Protecting jobs and re-opening the economy were not high priorities.…”