How COVID-19 vaccines are impacting the timing of everything from mammograms to chemotherapy
|Toronto Star 19 Mar 2021 at 14:55|
With the province moving to a 16-week interval between the first and second dose of COVID-19 vaccines , breast-imaging professionals and radiologists across Canada are recommending screening mammograms be performed four to six weeks after either jab.
A recommendation drawn up in early February, suggested patients and providers consider screening prior to the first dose of a COVID-19 vaccine or four to six weeks after the second dose. But with the new delay between the first and second dose, Dr. Jean Seely said she is concerned the initial recommendation may pose a risk to women who really need a mammogram, especially with breast cancer screenings already delayed due to the pandemic.
“We are seeing a lot of the impact of the delays of people not getting screened,” said Seely, president of the Canadian Society of Breast Imaging (CSBI) and head of the breast imaging section of the department of medical imaging at The Ottawa Hospital. “To be vaccinated is also very important and doing both is really critical from a public health standpoint.”
Mammograms are just one of a number of treatments or procedures, from chemotherapy to spleen removals, whose timing may be impacted by COVID vaccinations.
The Moderna and Pfizer vaccines can cause swelling in the lymph nodes in the underarm and collarbone area; 11.6 per cent of recipients of the Moderna vaccine aged 18 to 64 experienced this following the first dose, with 16 per cent reporting new lumps after the second shot. While swelling of the lymph nodes on the same side a patient received a COVID-19 jab is “a sign the vaccine is working,” it could lead to a false reading on a mammogram, Seely said.
Like with breast cancer, lung cancer and melanoma can spread to neighbouring lymph nodes, which is why recommendations coming out of other countries like the United States suggest lung cancer screenings be delayed by up to six weeks as well, Seely noted.
In addition to cancer screenings, undergoing chemotherapy, other types of vaccines and even having a spleen removed or getting a case of the common cold can all affect the best timing to receive a COVID-19 jab.
People undergoing chemotherapy for cancer should wait until the end of their planned cycle to schedule a COVID-19 vaccination, ideally between two to four weeks after their last dose of treatment, said Dr. Gerald Evans, an infectious disease specialist at Queen’s University.
“We know chemotherapy can impact the immune system in terms of reducing the cells that need to respond to the vaccine,” Evans said.
Sometimes a COVID-19 vaccine can be administered to a patient who has two to three chemo-free weeks before their next cycle begins, but a conversation between the patient and their oncologist needs to take place first.
There are some other unique circumstances that can impact vaccine timing, Evans explained. For example, people who need to have their spleen removed should be vaccinated a couple weeks prior or four weeks after the surgery, because the spleen carries a lot of “effector cells,” which produce a response to a stimulus like a vaccine.
People who are dealing with an acute infection or inflammatory condition — like a common cold — can wait a week or so before receiving the vaccine to allow for the best immune response. Those who have actually had COVID-19 should be recovered before sitting down for a vaccine, Evans said.
Currently, no data exists on the simultaneous administration of COVID-19 vaccines with other vaccines. In the absence of evidence, The National Advisory Committee for Immunization (NACI) recommends waiting for a period of at least 28 days after each COVID-19 vaccine dose before receiving another vaccine. The recommendation is a precaution to minimize potential adverse events, like interference in the immune response of each vaccine and unwanted or unexpected health effects, said Dr. Susy Hota, medical director of infection prevention and control at the University Health Network in Toronto.
“Would it reduce the effectiveness? Would it actually enhance it? Or do nothing? We just don’t know,” she said. “If you have a side effect that’s more serious, you’d want to know which vaccine caused it. There could be components in those vaccines you need to avoid.”
One exception to the rule is post-exposure prophylaxis or PEP, a short course of HIV medicine taken very soon after a possible exposure to prevent HIV infection.
Some physicians may suggest tapering down their patient’s use of immunosuppression medications, like Prednisone, to give them the best possible chance of a good immune response to the vaccine, Hota explained. Patients on anticoagulants (medicines that prevent blood clots) who can safely hold off on taking them can reduce the risk of bruising and bleeding after a vaccine, but immunizations are typically given to people on standard doses of anticoagulants without any harm at all.
“It’s hard to put out a blanket statement. These are all critical judgments that should be made by a patient’s physician,” she said.
“Don’t freak out about it. We need to investigate it,” she said. “But we can expect more cautious recommendations, like waiting, to loosen over time as we get more comfortable with the vaccine.”