Now, there is a complex global situation where populations in different countries have unique hybrid immunity landscapes, born from a wide range of vaccination history and exposure history combinations.
In 2023, we needed to consider what hybrid immunity meant for booster vaccinations. And what different types of hybrid immunity meant for future vaccination strategies.
The new projection suggests that more than 23 percent of the global population of these older adults — largely concentrated in Africa and Asia — will encounter this intense heat, compared with 14 percent today.