Patients with lymphoma may be immunosuppressed to a varying extent depending on the lymphoma diagnosis and treatment history. This has implications for overall vaccination strategy and treatment decisions.
Safety and efficacy of COVID-19 vaccines in immunocompromised patients
There are no data regarding the safety or efficacy of currently available COVID-19 vaccines in immunosuppressed patients. However, there is no a priori reason to believe that replication-deficient vaccines should be unsafe in this setting. Regarding clinical efficacy, it is reasonable to assume that patients with B-cell depletion/dysfunction are likely to have an impaired humoral response to vaccination, while those with T-cell depletion/dysfunction are likely to have an impaired cellular response and possibly also an impaired humoral response due to loss of T helper function.
Overall COVID-19 vaccination strategy
Based on current safety/benefit considerations and in the absence of data or guidance to the contrary, we recommend that all patients with lymphoma should receive a non-replicating COVID vaccine (unless explicitly contraindicated), accepting that this might not achieve full protection if there are pre-existing defects in humoral and/or cellular immunity. For these patients, vaccination of close contacts may be at least as important. It should be emphasised that neither of these measures removes the need for social distancing.
Implications for lymphoma treatment
The predicted effects of specific lymphoma treatments on cellular and humoral responses to COVID-19 vaccination should be considered and discussed with patients in a balanced way alongside other treatment considerations, e.g. the desire to maximise progression-free survival and minimise overall treatment-related toxicity. This is particularly relevant for drugs such as bendamustine and rituximab, which deplete T and B cells, respectively, but may also improve long-term disease control.
Timing of COVID-19 vaccines
COVID-19 vaccination should be timed with the aim of achieving optimal protection at the earliest opportunity without compromising lymphoma outcome. Where possible, vaccination should be completed at least 2 weeks before any immunosuppressive treatment is given. For patients who have already received immunosuppressive treatment, the advantages and disadvantages of interrupting therapy or delaying vaccination to allow immune recovery requires careful consideration and discussion bearing in mind that short interruptions in treatment may not be sufficient for any meaningful improvement of immune function. For patients in clinical trials the timing of vaccination should be discussed with the relevant co-ordinating centre.