Effects of previous infection, vaccination, and hybrid immunity against symptomatic Alpha, Beta, and Delta SARS-CoV-2 infections: an observational study

https://www.thelancet.com/journals/ebiom/article/PIIS2352-3964(23)00299-2/fulltext?dgcid=hubspot_email_covidalerts&utm_campaign=covidalerts&utm_medium=email&_hsmi=271757280&_hsenc=p2ANqtz--FwVty6ygfadJEbwkrGF2_UDogR2OYmmkEHuy2GAX36-7KgJpT6rUq8HupPkqBhnyPKpYlftOHAOgPG8cBitfScFYw3g&utm_content=271743104&utm_source=hs_email