WHO is releasing our updated Strategic Preparedness, Readiness and Response Plan for COVID-19.

This is our third strategic plan for COVID-19, and it could and should be our last.

It lays out three possible scenarios for how the pandemic could evolve this year.

Based on what we know now, the most likely scenario is that the virus continues to evolve, but the severity of disease it causes reduces over time as immunity increases due to vaccination and infection.

Periodic spikes in cases and deaths may occur as immunity wanes, which may require periodic boosting for vulnerable populations.

In the best-case scenario, we may see less severe variants emerge, and boosters or new formulations of vaccines won’t be necessary.

In the worst-case scenario, a more virulent and highly transmissible variant emerges. Against this new threat, people’s protection against severe disease and death, either from prior vaccination or infection, will wane rapidly.