She was young — just a few years younger than me. My eyes were locked on the monitor, willing it to show a heartbeat. It never did. We did CPR. We used every medication, every intervention we could. But it wasn’t enough.

She had arrived at the hospital with a severe bloodstream infection — one that should have been treatable. By the time she got to us, her illness had progressed to multisystem organ failure. Not even the most advanced antibiotics and life support could save her. I still think about her. I still wonder if there was something we could have done differently, even though I know the answer is no.

I am about to finish my internal medicine residency here in western Massachusetts, and in a few short months, I could be practicing as an independent physician. Instead, I have chosen to continue my training in infectious diseases. I have spent years preparing to fight, treat, and prevent infections like the one that took this young woman’s life. And yet, despite all our medical advances, infectious diseases, many of which we know how to prevent and treat, still kill people.

I will begin my fellowship at a precarious time for public health. Diseases we once had under control are making a resurgence. Decades of well-established science — science that has protected millions of lives — is now being questioned.

Large-scale measles outbreaks, once almost unheard of in modern America, are occurring again, especially in under-vaccinated communities. I fear having to tell a grieving parent, a devastated spouse, or an adult child that their loved one — whether a child, an elderly parent, or someone with a chronic illness — won’t make it because of a disease we had nearly eradicated.

The heartbreaking reality is that measles, and many other vaccine-preventable illnesses, should not be killing or making people ill in 2025. And yet vaccination rates are falling. Nationally, the decline may seem small, but in certain communities, rates have dropped dangerously low.

The Massachusetts Department of Health and Social Services found that kindergartner vaccine rates in Hampden, Berkshire, and Franklin counties in the 2023-24 school year fell below the 92% threshold needed to protect those who cannot be vaccinated from measles. When too few people are vaccinated, herd immunity weakens, allowing these diseases to return to our communities.

I understand why people have questions about vaccines. Medical science is complex. I’ve spent over a decade studying it and have more years to go. It is also not always clearly communicated to the public in a way that is easy to understand. Misinformation spreads faster than facts, and sometimes by sources that may not prioritize public and personal health. It’s understandable to have questions, but fear should not replace evidence.

The truth is clear: Vaccines are safe, effective, and necessary. The human body is remarkable and resilient, but it is also vulnerable. Many who are skeptical of vaccines argue that natural immunity is superior or that vaccine side effects are worse than the diseases themselves.

But even if someone recovers from measles, the virus can linger in their body and spontaneously cause deadly brain swelling years later that is almost always fatal. This means “natural immunity” isn’t always enough — it comes with risks we can’t undo. There is plenty of evidence to support the safety of vaccines, but we do not have a treatment for irreparable brain damage. Our youngest and most vulnerable are at the highest risk of this devastating condition.

I worry about what the future holds if we continue down this path. I don’t want to stand at a patient’s bedside, knowing their suffering could have been prevented. I don’t want to have to tell a family that there is nothing more we can do. And I don’t want to lie awake at night wondering if I did enough to stop this dangerous trend.

As health care professionals, we dedicate our lives to protecting and healing others. But we cannot do it alone. Protect yourself and your community, talk to your doctor, stay informed, and ensure your family is up to date on vaccinations. If you have concerns, ask a medical professional, not social media.

Science has already given us the tools to prevent these diseases. We just have to use them before it’s too late.

Dr. Julia Fischer lives in Springfield.