Study Title: Breakthrough SARS-CoV-2 infections among patients with cancer following two and three doses of COVID-19 mRNA vaccines

Publication (online): The Lancet Regional Health - Americas, February 13, 2023

Dana-Farber Cancer Institute author: Toni Choueiri, MD; Chris Labaki, MD; Ziad Bakouny, MD, MSc



Breakthrough SARS-CoV-2 infections following vaccination against COVID-19 are of international concern and patients with cancer are highly vulnerable and susceptible to poor outcomes. It is recommended that patients with cancer receive a 3-dose COVID-19 vaccination series but it is noted that their immunological response to the vaccine series may be lessened, notably among those with hematologic malignancies. Utlizing data from the multi-institutional COVID-19 and Cancer Consortium (CCC19) scientists found vaccination with 2 or 3 doses of an mRNA vaccine prior to infection was associated with improved outcomes for patients with cancer diagnosed with COVID-19 in 2021 or 2022. Across all endpoints, including 30-day morality, ICU admission and hospitalization, the vaccine benefit was most pronounced for those patients receiving 3 doses. 


This study shows vaccination against COVID-19 is an essential strategy to improve outcomes in this high-risk population. The results support guidelines that patients with cancer should receive at least 3 COVID-19 vaccine doses. This analysis represents one of the largest cohorts with comprehensive clinical and biological data on vaccinated patients with cancer and breakthrough COVID-19 to date and is one of the first studies to evaluate breakthrough infections following the receipt of 3 doses of mRNA vaccines among patients with cancer.


The research was partly supported grants from the National Cancer Institute (P30 CA068485; T32-CA236621; P30-CA046592); CTSA 2UL1TR001425-05A1; ACS/FHI Real-World Data Impact Award, P50 MD017341-01, R21 CA242044-01A1, Susan G. Komen Leadership Grant Hunt. REDCap is developed and supported by Vanderbilt Institute for Clinical and Translational Research grant support (UL1 TR000445 from NCATS / NIH).

Register for reporter access to contact details

The Lancet Regional Health - Americas, Feb-2023; P30 CA068485; T32-CA236621; P30-CA046592; 2UL1TR001425-05A1; P50 MD017341-01; R21 CA242044-01A1; UL1 TR000445