However, we have yet to see published data from the United Kingdom and other countries that have more experience administering the AstraZeneca vaccine to confirm this. So it’s likely we’ll also see it with other COVID vaccines. However, as activating the immune system is how all vaccines work, we’ve seen similar swelling after vaccines other than COVID. This is the vaccine earmarked for the over-50s in Australia from May. This led to swollen lymph nodes showing up on breast imaging, including mammography and ultrasound.Īccording to the Royal Australian and New Zealand College of Radiologists, this type of swelling has not been reported with the AstraZeneca vaccine.

Reports of COVID vaccine-related swollen lymph nodes emerged from the United States, where almost 90 million people have been vaccinated with the Pfizer or Moderna vaccines. So it’s important to note this potential impact of COVID vaccination on mammography, ahead of Australia ramping up its vaccine rollout, especially in the over-50s. This can lead to further imaging, invasive procedures such as biopsies, and patient anxiety. This can have important consequences.Īn enlarged lymph node may cause a woman to have further testing to confirm or rule out breast cancer. This is because it looks like breast cancer that has spread (metastasised) from the breast to the lymph node. However, a swollen lymph node can affect imaging such as breast cancer screening by mammography or ultrasound. They also disappear within one or two weeks of vaccination.Įxplainer: how does the immune system work? It’s important to stress these lumps are not breast cancer, and are not harmful. While estimates vary, only about one in ten people vaccinated can feel a lump there, and it’s not always painful. It’s your body preparing a protective immune response.Īfter their COVID shot, some people develop more severe swelling in the armpit than others. When people have vaccines in their upper arm, it’s normal for the lymph nodes in the armpit on that side of the body to be activated and swell.

Painful lump in armpit