What is the immune protection generated by SARS-CoV-2 Delta and Omicron BA.1 and BA.2 against Omicron BA.4 and BA.5?

Researchers evaluated immune protection conferred by previous SARS-CoV-2 Delta variant and Omicron BA.1/BA.2 subvariant infections and updated vaccines against Omicron BA.4/5 infections and associated hospitalizations.