Comparing the impact of vaccination strategies on the spread of COVID-19, including a novel household-targeted vaccination strategy

Abstract

With limited availability of vaccines, an efficient use of the limited supply of vaccines in order to achieve herd immunity will be an important tool to combat the wide-spread prevalence of COVID-19. Here, we compare a selection of strategies for vaccine distribution, including a novel targeted vaccination approach (EHR) that provides a noticeable increase in vaccine impact on disease spread compared to age-prioritized and random selection vaccination schemes. Using high-fidelity individual-based computer simulations with Oslo, Norway as an example, we find that for a community reproductive number in a setting where the base pre-vaccination reproduction number R = 2.1 without population immunity, the EHR method reaches herd immunity at 48% of the population vaccinated with 90% efficiency, whereas the common age-prioritized approach needs 89%, and a population-wide random selection approach requires 61%. We find that age-based strategies have a substantially weaker impact on epidemic spread and struggle to achieve herd immunity under the majority of conditions. Furthermore, the vaccination of minors is essential to achieving herd immunity, even for ideal vaccines providing 100% protection.

Modeling geographic vaccination strategies for COVID-19 in Norway

“…Furthermore, the geographic prioritization across populations is associated with age subsequently because of the individual-level prioritization within populations. The trade-off between infections and deaths is mainly due to the age-specific contact and risk as shown in several studies on age prioritization [ 16 – 27 ]. Many of the studies agree that prioritizing the elderly is the optimal strategy to prevent deaths directly, and so as our assumptions in the models to prioritize in a descending age order, starting with those older than middle-aged with higher risk.…”

Using a real-world network to model the trade-off between stay-at-home restriction, vaccination, social distancing and working hours on COVID-19 dynamics

“…Many countries, such as Singapore and the United Arab Emirates, have more than 80% ( Reuters, 2021 ) vaccination ratios, but they had cases when the delta variant was dominated ( Worldometer, 2021a ; Worldometer, 2021b ). Voigt, Omholt & Almaas (2022) have investigated the impact of vaccination on reproduction number. They have found that for both delta and wild-type variants vaccinating 80% of population does not bring reproduction number below 1.…”

Data-driven Targeting of COVID-19 Vaccination Programs: An Analysis of the Evidence on Impact, Implementation, Ethics and Equity

“…26 By contrast, 18 of the 74 studies found that targeting vaccination of those most likely to spread COVID-19 -including younger age cohorts and/or essential workers -to reduce transmission was a more effective strategy than targeting those most vulnerable to severe illness. Of these, 17 prioritized high contact [27][28][29] or high transmission groups including the young, [30][31][32][33][34] the socially connected, 35,36 adults in large households and multi-generational homes, 37,38 migrant workers 39 or places with high population density 40 or case growth. [41][42][43] One found that targeting based on the presence of SARS-CoV-2 antibodies would be optimal.…”