Vaccine optimization for COVID 19: Who to vaccinate first?
The optimal use of COVID 19 vaccine depends mainly on how efficacious the vaccine is and how many doses are available. Vaccines, when available, will likely become our best tool to control the COVID 19 pandemic. Even in the most optimistic scenarios, vaccine shortages will likely occur. Using an age stratified mathematical model paired with optimization algorithms, we determined optimal vaccine allocation for four different metrics (deaths, symptomatic infections, and maximum non ICU and ICU hospitalizations) under many scenarios. We find that a vaccine with effectiveness =50% would be enough to substantially mitigate the ongoing pandemic, provided that a high percentage of the population is optimally vaccinated. When minimizing deaths, we find that for low vaccine effectiveness, irrespective of vaccination coverage, it is optimal to allocate vaccine to high risk (older) age groups first. In contrast, for higher vaccine effectiveness, there is a switch to allocate vaccine to high transmission (younger) age groups first for high vaccination coverage. While there are other societal and ethical considerations, this work can provide an evidence based rationale for vaccine prioritization.
Science Advances