Each one of us has around 600 lymph nodes (LNs) – small, bean-shaped organs that house various types of blood cells and filter lymph fluid – scattered throughout our bodies. Many of us have also experienced some of our LNs to temporarily swelling during infections with viruses or other pathogens. This LN expansion and subsequent contraction can also result from vaccines injected nearby, and in fact is thought to reflect the ongoing vaccine immune response. While researchers have studied the early expansion of LNs following vaccination, they have not investigated whether prolonged LN expansion could affect vaccine outcomes.
