Remaining adhered to all protective measures and getting inoculated with variant specific vaccines against Covid-19 are still high priorities for protecting the immunocompromised. For cancer patients, in particular, Covid-19 poses a high risk due to their often compromised immune systems, weakened by therapy or disease. A recent study led by Medical University Vienna showed that, due to Omicron, there is a significantly increasing number of breakthrough infections in people with cancer, especially while they are undergoing cancer therapy. The researchers of the study, which has just been published in the journal Cancer Cell, found that a total of 950 of the 3,959 cancer patients (24%), who have been under treatment at the University Hospital Vienna and Franz Tappeiner Hospital in Merano, Italy, between February 2020 and February 2022, had become infected with the SARS-CoV-2 virus. At least 85 percent of these 3959 patients were inoculated with one of the Covid vaccines approved in Europe.