THE PROBLEM

The last great global influenza pandemic of 1918-19 is estimated to have killed more than 60 million people. In today’s world population, the death toll would have been nearly 200 million. The best predictive models we have today suggest that there is at least a 50/50 chance that another major pandemic will occur in the next 20 years, with influenza pandemic risk estimated to be 75% higher than that of coronavirus. This could result in at least 16 million deaths, unless we prepare by developing and deploying more impactful vaccines and other non-pharmaceutical measures like lockdowns and masks. Unlike in 1918, influenza vaccines now exist. However, past pandemics have taught us that delays in vaccine availability still translate directly into mass casualties. Therefore, the question is which kinds of improvements to influenza vaccines are most needed and which vaccine-related investments will lead to the greatest health benefits?

THE PHAROS SOLUTION

Our team, with financial support from CEPI and others, explored these questions by modeling the expected impact of different pandemic influenza vaccine scenarios. Our work compares the health impact of alternative vaccine platforms and programmatic enablers during an influenza pandemic, allowing decision-makers to weigh investments in “better vaccines” (e.g., higher effectiveness and longer durability) along with investments in “faster systems” (e.g., manufacturing scale-up and regulatory acceleration).

To address these questions, we:

• Built a deterministic SEIR (susceptible-exposed-infected-recovered) transmission model to quantify how different vaccine development pathways improve pandemic outcomes.
• And evaluated four vaccine platforms to span the main technologies that are either licensed for pandemic influenza or under development for future influenza pandemic response, along with two primary programmatic enablers that modify manufacturing and deployment speed.

Our results show that the speed to first protection and the rate of vaccine rollout are the primary drivers of pandemic outcomes, particularly in faster-moving epidemics with higher rates of infection. In practical terms, investments in platforms that can be deployed rapidly (notably mRNA and recombinant vaccines), along with financing to enable surge manufacturing, avert substantially more deaths than strategies that rely on later-arriving products, even when those products are highly effective.

LOOKING AHEAD

Our model is a tool that can answer pressing questions for pandemic preparedness, while also setting clear quantitative goals for vaccine manufacturers, governments, and international organizations. The model is designed to further evaluate the benefit of vaccine strategies including:

• Mass vaccination scenarios arising from R&D investments in improved vaccines
  
• Universal vaccines and targeted vaccination scenarios for vulnerable populations
  
• Combining public health and social measure (PHSM) strategies with vaccines
  
• Accounting for the indirect benefits of vaccination which can provide greater economic returns on investment and have implications for public policy.

By translating future pandemic scenarios into tangible human and economic outcomes, our work highlights the enormous cost of inaction and emphasizes the benefits of alternative pathways that could save millions of lives and trillions of dollars in economic output. Click on the attached policy brief and modeling overview to learn more about our findings.

Status: Completed December 2025

Team Members Involved: Angela Chang, Christian Berrig, Alyssa Agarwal, Mariam Mubarak-Gabrian, Robert Hecht, Dean Jamison.