There is new insight on the COVID-19 vaccine and how it can impact your body.|| COVID-19 updates | Maryland's latest numbers | Get tested | Vaccine Info ||As with most vaccines, it triggers an immune response, so your body is better prepared to fight if you are exposed to the virus.That is causing some people to notice enlarged lymph nodes that linger, sometimes months after.The doctor who spoke with 11 News said she doesn't want this to lead to hesitancy or fear about the vaccine or mammograms — it is about having the knowledge about what to possibly expect.Since the COVID-19 vaccine rollout began, there has been knowledge of one possible side effect: enlarged lymph nodes and they might show up on a mammogram or ultrasound, but now doctors are noticing even more."What we noticed is that lymph nodes actually were enlarged for a longer period of time," said Dr. Lisa Mullen, a radiologist at Johns Hopkins Medicine. Mullen explained that enlarged lymph nodes after getting the vaccine is a normal and often expected immune response but now, in some cases, doctors doing mammograms and ultrasounds are seeing the larger lymph nodes persist for months longer than initially predicted."The original follow-up recommendation was follow up in four to 12 weeks, with the expectation that the lymph node would have all come down to normal size during that time period. What we actually found is that for some patients they persisted in being enlarged beyond the three-month mark," she said.And that is leading to more follow ups and in some cases biopsies.Mullen emphasizes that should not stop people from getting vaccinated or getting their regular mammogram screenings, but it's important to be aware, especially as more people are getting their boosters."We may be calling them back in to look at those and that may initiate that follow up pathway, but even though that seems alarming, it really is not related to breast cancer and we just want to be as cautious as we can be," Mullen said.Mullen said they're still learning about who is most affected by enlarged lymph nodes that persist after vaccination and for how long. She expects more studies in the months ahead."Hopefully, over the next several months we'll gain additional understanding of this process and have updated guidelines to share with the public," she said.For people who have experienced the issue, some health experts are recommending getting the booster in the opposite arm from where you received the initial vaccine series.Mullen said it also could be a good idea to wait a couple weeks between flu vaccine and booster.