COVID-19 Breakthrough Infections among Patients with Cancer Receiving Sinopharm BIBP Vaccine

Background: Patients with cancer are at an increased risk of mortality from COVID-19 infection. So, they are prioritized for vaccination. However, there is limited data about the immunogenicity, safety, and effectiveness of inactivated vaccines in preventing COVID-19 infection, hospitalization, and mortality in patients with cancer. Objectives: This study aimed to report the clinical characteristics of patients who had a positive PCR test after being fully vaccinated with the Sinopharm BIBP Vaccine. Methods: In this retrospective study, the data of patients with cancer were extracted from the electronic health records of a cancer center in Isfahan, Iran. All COVID-19 data from Isfahan province also was collected by Isfahan COVID-19 Registry (I-CORE). We described the clinical characteristics of patients with cancer who have a positive test more than14 days after the second dose. Results: Two hundred twenty-two patients with cancer had at least one positive PCR test after the start of the COVID-19 vaccination. Of these, 9 (4.1%) breakthrough infections have occurred. Six (67%) of them had hematological malignancies. Six (67%) were hospitalized and 3 (33%) patients died. Two of them had recent chemotherapy and have hematological malignancies. Conclusions: Vaccination is a good way to protect the population from COVID-19 complications and mortality, but it should be considered that fully-vaccinated patients with cancer are at risk of severe outcomes. Nevertheless, prioritizing cancer patients, especially those with hematological malignancies, or receiving chemotherapies for booster vaccines and studying the effectiveness of each COVID-19 vaccine for patients with cancer should be considered.