The SARS-CoV-2 pandemic is shaking the lives of us all, but especially those who are more vulnerable and at higher risk of contracting the infection, or developing a more serious clinical condition. Oncology patients are within this group.

This has led the main national and international oncological societies to take a position on the vaccination of oncology patients, issuing a series of general recommendations, among which are:

1. Vaccination is a priority for patients who have active oncological disease and/or are undergoing active, potentially immunosuppressive antitumour therapy.
2. While there are limitations in the supply of vaccines, it will be necessary to prioritize the strategies of vaccination of cancer patients with active disease and/or antitumour treatment, although the recommendation remains to vaccinate ALL patients diagnosed with cancer, including those who are in complete remission and in follow-up care, as soon as possible.
3. There is no contraindication to vaccination during cancer treatment although, where possible, it is recommended to do so before starting treatment. If cancer treatment has already begun, there is no specific data on the time of the cycle at which it is preferable to administer the vaccine.

While some of the public’s reservations about being vaccinated against SARS-CoV-2 is understandable, either because of the new mechanism of action of some vaccines and their rapid clinical development, or because of the lack of data about efficacy and/or long-term safety, there is no doubt that the benefits of vaccination clearly outweigh the risks.

These concerns increase in cancer patients, as vaccines have not been specifically tested on them. But this has happened in the past, without being the subject of so much controversy, with other vaccines such as the flu vaccine; this is also recommended to be administered systematically to cancer patients, without having been specifically tested on them.

A priori, the side effects of a vaccine in a cancer patient should not be different to those observed in the rest of the general population, but oncology societies insist, nonetheless, on the importance of collecting data after the vaccination of cancer patients to monitor possible adverse effects, as well as efficacy and immune response.