Network models to evaluate vaccine strategies towards herd immunity in COVID-19

Highlights

• Stochastic network modelling to evaluate vaccine strategies in COVID-19.

• High-performance computing to evaluate COVID-19 pandemic scenarios.

• At least 70% of a given population should be vaccinated to obtain herd immunity.

• Ring of Vaccination is a promising scheme to prevent the new waves of COVID-19.

Abstract

Vaccination remains a critical element in the eventual solution to the COVID-19 public health crisis. Many vaccines are already being mass produced and supplied in many countries. However, the COVID-19 vaccination programme will be the biggest in history. Reaching herd immunity will require an unprecedented mass immunisation campaign that will take several months and millions of dollars.

Using different network models, COVID-19 pandemic dynamics of different countries can be recapitulated such as in Italy. Stochastic computational simulations highlight that peak epidemic sizes in a population strongly depend on the network structure. Assuming a vaccine efficacy of at least $80\%$ in a mass vaccination program, at least $70\%$ of a given population should be vaccinated to obtain herd immunity, independently of the network structure. If the vaccine efficacy reports lower levels of efficacy in practice, then the coverage of vaccination would be needed to be even higher. Simulations suggest that the “Ring of Vaccination” strategy, vaccinating susceptible contact and contact of contacts, would prevent new waves of COVID −19 meanwhile a high percent of the population is vaccinated.