Infection is one of the most common life-threatening complications of cancer and cancer treatment. Immunosuppression resulting from cancer and chemotherapy places patients at a higher risk of contracting infections, as well as increasing the severity of infection. In the general population, vaccination is a simple yet important process used to prevent many infections. However, studies have indicated that immunosuppression reduces the effectiveness of the vaccines. Studies have reported the rates of development of detectable antibodies (also known medically as seroconversion) in the blood of cancer patients after vaccination range from 25% to 71%, compared with 67% to 88% in controls1. For a healthy immune system, it typically takes up to 2 weeks after vaccination for the immune system (adaptive immunity) to respond to the exposed pathogen. Unfortunately, cancer patients may not be able to mount an adequate immune response within this time. Although vaccination appears to be less effective in cancer patients, it does have a role to confer protection to some patients and lessen the severity of infection in others. Repeat vaccination or boosters may be crucial in prolonging and/or extending immunity.
Stem cell transplants are used in some patients with certain types of cancer, such as leukaemias, lymphomas and myelomas, after completion of chemotherapy in an attempt to rid all cancer cells from the body. In patients undergoing transplant, the loss of pre-transplant immunity is inevitable. Following the suppression on the immune system, the body’s natural course of recovery begins at the blood cell line (at 2 to 4 weeks), followed by B lymphocytes and T lymphocytes recovery at approximately 1 to 3 months post-transplant2,3. Immunisation with killed or inactivated vaccines does not represent a danger to immunosuppressed patients. The timing of vaccinations with respect to the treatment is important in achieving extended immunity and better outcomes for cancer patients. Ideally, vaccination should precede the commencement of chemotherapy by at least two weeks. Vaccination during chemotherapy or radiation therapy should be avoided because antibody responses are suboptimal. However, this may not be feasible, given the need to start chemotherapy regimens in a timely manner. If vaccines are given during chemotherapy, they should not be considered valid doses unless protective antibodies are documented4.
Live-virus vaccines such as measles-mumps-rubella (MMR), Varicella Zoster and Bacille Calmette-Guerin (BCG), are contraindicated in immunosuppressed patients and should be deferred until immune function has returned to normal. Virus replication after administration of live, attenuated-virus vaccines can be enhanced in severely compromised persons resulting in serious or unusual adverse events4,5. Nevertheless, patients with leukemias, lymphomas or other malignancies whose disease is in remission and whose chemotherapy has been terminated for at least three months may receive live vaccines6.
Special consideration: Patients on immune checkpoint inhibitors
Data is lacking on the recommendations for vaccinations in cancer patients receiving checkpoint inhibitors such as pembrolizumab, nivolumab and ipilimumab. No controlled clinical trials have been conducted to investigate the combination of influenza vaccines with immune checkpoint inhibitors. However, extreme caution is recommended in patients receiving ipilimumab and nivolumab, as serious adverse events have been reported in patients who had received concomitant influenza vaccine prior to or during treatment with this combination therapy7. The decision on whether or not to immunise a patient lies in the hands of the clinicians who will consider the risk versus benefit on a case by case basis.
In summary, childhood vaccination has led to the elimination of many preventable diseases in the general population. Likewise, the same approach has shown to be beneficial in the haematology and oncology population. Immunisation can reduce the incidence and severity of infections, and optimal timing of vaccine administration can further increase the chance of successful protection. Avoidance of live vaccines is crucial in this group of patients.
- Ariza-Heredia EJ, Chemaly RF. Practical review of immunisations in adult patients with cancer. Human Vaccines and Immunotherapeutics. 2015;11(11): 2606-2614.
- Tsang V. Vaccination recommendations for the hematology and oncology and post-stem cell transplant populations. Journal of the Advanced Practitioner in Oncology. 2012;3(2): 71-83.
- Singhal S, Mehta J. Reimmunisation after blood or marrow stem cell transplantation. Bone Marrow Transplant. 1999;23: 637-646.
- Hibberd PL. Immunisations in patients with cancer. UpToDate. Available from: www.uptodate.com [Accessed: 19th January 2017].
- Davis LE, Bodian D, Price D, Butler IJ, Vickers JH. Chronic progressive poliomyelitis secondary to vaccination of an immunodeficient child. New England Journal of Medicine. 1977;297: 241-245.
- Centers for Disease Control and Prevention. Recommendations of the advisory committee on immunisation practices (ACIP): Use of vaccines and immune globulins in persons with altered immunocompetence. Morbidity and Mortality Weekly Report. 1993;42(RR-4). Available from: https://www.cdc.gov/mmwr/pdf/rr/rr4204.pdf [Accessed: 19th January 2017].
- Bristol-Myers Squibb medical information, 27 March 2017.