COBRA-KAI study: COVID-19 vaccination in patients with reduced B-cell and T-cell immunity: response after vaccination of a kaleidoscopic group hematological patients, what's the impact?

In patients with an underlying hematological disease, vaccination is often refrained from, because it is still questionable whether vaccination provides sufficient protection. This study investigates whether this is correct. The researchers expect to be able to identify patient groups that, contrary to expectations, respond well to vaccination. It is also being examined whether patients who are insufficiently protected after vaccination can be given additional protection by vaccinating household members (ring vaccination) and whether patients themselves can be given a 'booster' vaccination. Goal Mapping specific patient groups that are (in)sufficiently protected after the standard COVID-19 vaccination schedule, and whether one or more additional (booster) COVID-19 vaccination(s) for patients who are insufficiently protected leads to adequate protection against COVID-19. Background COVID-19 additional risk in hematological diseases Patients with a hematological disease, such as leukemia or lymphatic cancer, often have a weakened immune system. This greatly increases the risk of a serious course of a COVID-19 infection. For example, the risk of death from sickle cell disease is even 6 times greater. Doubts about the effect of vaccination At the same time, it is questionable whether vaccination works well in these patients, because their immune system may be less able to build up immunity. This may be due to the disease itself or due to treatments that suppress the immune system. This is the reason why vaccination is often refrained from in these patients. Additional knowledge required for optimal protection To optimally protect this patient group, more research is needed into the effect of COVID-19 vaccinations. This study not only examines whether patients with a hematological disease are well protected after vaccination, but also whether one or more additional (booster) COVID-19 vaccination(s) leads to adequate protection in patients who do not build up sufficient immunity. after standard COVID vaccination schedule, and how long this protection lasts. After all, shorter protection may be a reason for additional vaccination. The researchers will also map parts of the immune system that predict which patients can build up a good immune system and which cannot. The results of this research will be used to improve vaccination guidelines and advice. Research design We follow 850 patients In this study, we will measure the response of the immune system to the vaccination in 850 patients with hematological diseases who are vaccinated against COVID-19. For this purpose, blood is taken from patients both before vaccination and at fixed time points afterwards. Various aspects of the immune response against SARS-CoV-2 will be measured in this blood, such as antibodies and the functioning of cells of the immune system (B and T cells). Data from patients will also be collected, such as the precise hematological diagnosis, previous anti-cancer treatments, current treatment and medication use. Booster vaccination Patients who have not built up sufficient immunity after a standard COVID vaccination schedule will receive a booster vaccination, after which it will be investigated whether sufficient immunity has been built up or whether an additional booster vaccination is needed. Patients who initially show a response to the standard vaccination schedule but do not show sufficient immunity after 6 months will also receive a booster vaccination. Expected results After the research, we expect to be able to identify patient groups that, contrary to expectations, respond well to the standard vaccination schedule. On the other hand, we can define patient groups in which it is possible to build up adequate immunity against COVID-19 through booster vaccinations. For patients who are insufficiently protected even after booster vaccination, additional protection can be generated after vaccination by vaccinating housemates (ring vaccination). This knowledge can also be applied to annual vaccination campaigns against flu and other pathogens.