Understanding how COVID-19 severity relates to virus variants and vaccines

This is an international research study that collects medical information and blood samples from adults hospitalized with COVID-19. Researchers are trying to understand how different variants of the virus (like delta and omicron) and different vaccines affect how sick people become and how well treatments work.

Since the start of the pandemic, new COVID-19 variants have emerged around the world, but doctors don't fully understand how these variants affect vaccinated and unvaccinated people differently, or how they respond to treatment. This study aims to fill that gap so hospitals can better manage and treat COVID-19 patients.