Cancer patients are more vulnerable to COVID-19 infection and, above all, are at a higher risk of complications, especially those with disseminated disease and those undergoing chemotherapy. The COVID-19 pandemic has had, and continues to have, a serious impact on the world’s population, including people with cancer, their families and caregivers.
Vaccines are used to help a person’s immune system recognize and protect the body against certain infections. Vaccines against the virus that produces COVID-19 have been shown to significantly reduce the risk of COVID-19 infection, as well as the risk of serious illness, being hospitalized or dying if infected.
Currently in Spain we have four vaccines: Pfizer-BioNTech and Moderna, which are administered in two doses, three or four weeks apart; the Johnson & Johnson vaccine (Janssen), which is administered as a single injection; and the AstraZeneca vaccine, which is administered in two doses with an interval of up to twelve weeks.
Types of vaccine for COVID-19
Pfizer-BioNTech and Moderna vaccines contain messenger RNA (mRNA), which is a type of genetic material. Once the vaccine is administered, the mRNA enters the cells of our body and teaches them to make a protein, or a portion of a protein, which triggers an immune response within our body by producing antibodies, and this is what protects us from serious infections if the real virus enters our body.
The Johnson & Johnson (Janssen) and AstraZeneca vaccines contain an adenovirus or viral vector, a type of virus different from the one that causes COVID-19 and which is harmless. It has been modified in the laboratory to contain a DNA fragment of the COVID-19 virus, so that, when injected, it enters our cells and produces a harmless portion of the COVID-19 virus that is only present on their surface; our immune system recognizes that it does not belong to our body and this triggers an immune response by producing antibodies and activating other defence cells. This causes the immune system to recognize and attack the COVID-19 virus if the body is exposed to it in the future.
Although initial vaccine studies did not include cancer patients, most guidelines recommend vaccination of cancer patients, since none of the vaccines contain live viruses and the benefit of vaccination is considered to be much greater than the risk of vaccination.
Most common side effects in cancer patients
The most common side effects described after receiving vaccines include: pain and redness or swelling at the injection site, tiredness, headache, fever, chills, and pain in the muscles and joints. These side effects usually go away within a few days.
These symptoms are the same as those that may appear in patients with breast cancer, but it must be borne in mind that, if patients are undergoing cancer treatment, especially chemotherapy, the adverse effects can add up and, therefore, be of greater intensity. To counteract the side effects of the vaccine it is recommended to take 1g of paracetamol every 8 hours, alternating with 600mg of ibuprofen every 4 hours if they are very intense.
A very common adverse effect, especially in the case of patients with a history of breast neoplasia, is the appearance of swollen nodes in the armpit. It is an inflammation caused by the administration of the vaccine, related to the activation of the immune system. It has no relevance and will disappear in a few weeks; if this is not the case, then a medical assessment should be sought.
Patients with a history of breast cancer should be vaccinated, as far as possible, on the opposite side to the neoplasm and, if a complementary examination is performed (such as a mammogram or ultrasound), the radiologist should be made aware of the recent vaccination.
Currently there is no data that affirms that cancer patients have different adverse effects from the COVID-19 vaccine compared to the rest of the population. Some recent surveys have reported alterations in the menstrual cycle in relation to vaccination, but the scientific community still does not have enough scientific evidence to confirm this.