Understanding why the flu vaccine is important

I have had the privilege of serving as Chief Medical Officer at Bothwell Regional Health Center for the past 10 years. My medical training includes Internal Medicine as well as Pulmonary and Critical Care Medicine. For more than 30 years, I have also been closely involved in hospital pharmacy operations, infection prevention, patient safety and health care quality improvement at multiple institutions. I am grateful for the opportunity to share information about the importance of influenza vaccination and hope to provide insight that may not be widely understood.

Influenza vaccination in adults offers several important benefits. Vaccinated individuals are less likely to become infected. If infection does occur, vaccinated patients typically experience milder illness, with lower rates of hospitalization, ICU admission, shorter recovery times and reduced risk of death. Widespread vaccination also helps reduce transmission within the community.

The effectiveness of the influenza vaccine can vary from year to year depending on how closely the vaccine strains match circulating viruses. Even in years with a partial mismatch, vaccination continues to provide substantial protection against severe illness and death. This is particularly true for higher-dose influenza vaccines recommended for adults over age 65, which maintain strong protection even when strain matching is imperfect. Despite several mutations in the predominant strain during this flu season, early vaccine outcome data from England indicate improved health outcomes, including reduced infection rates and less severe illness.

Beyond preventing influenza infection and its complications, more than two decades of research demonstrate additional health benefits of influenza vaccination in older adults. These vaccine-related health benefits beyond protection from the target disease are referred to as “off-target” effects.  Influenza vaccine off-target effects include lower risks of hospitalization for heart failure and pneumonia, as well as reduced incidence of heart attack and stroke. Acute influenza infection places significant stress on the body and can impair respiratory function. In vulnerable individuals, this stress alone may be sufficient to trigger cardiovascular events or worsen chronic disease. The inflammatory response associated with severe influenza infection can also persist well beyond the resolution of acute symptoms, further increasing health risks.

Off-target effects of vaccination are not unique to the influenza vaccine. For example, strong evidence suggests that shingles vaccination (Shingrix) is associated with a reduced risk of dementia. A reduced risk of dementia development is also seen with the influenza vaccine. The exact mechanisms underlying these benefits are not fully understood.

One hypothesis for beneficial off-target effects of vaccination is that individuals who choose vaccination may be more health-conscious overall and engage in other behaviors that reduce their risk of other illnesses. While this may partially explain observed benefits, there is substantial evidence for a more direct benefit of vaccination, involving the role of inflammation in the development of vascular diseases such as stroke and heart attack. Individuals who are unvaccinated are more likely to become infected and to experience more severe illness, resulting in a greater inflammatory burden that may contribute directly to cardiovascular and neurologic complications.

In children, the benefits of influenza vaccination are primarily related to the prevention of influenza infection and its complications. Vaccinated children are less likely to become infected, experience milder illness if infected, and have a lower risk of serious complications such as pneumonia, dehydration, encephalopathy, sinus infections and in rare cases, death. Children with chronic conditions—including asthma, neurologic disorders, obesity and cardiovascular disease—are at significantly higher risk for severe influenza outcomes. Nearly three out of four children hospitalized with influenza have an underlying chronic health condition. As in adults, the stress and inflammation caused by influenza infection often worsen these existing illnesses.

Influenza vaccination remains an essential public health measure for adults and children. The benefits of vaccination far outweigh the risks of adverse effects and are especially critical for individuals with chronic health conditions who are most vulnerable to severe illness, hospitalization and death. For these individuals, influenza infection may be all it takes to trigger a major health crisis. Vaccination is a powerful and effective tool that can help reduce risk and improve outcomes, ultimately tilting the odds in favor of those most at risk.

Flu activity in Missouri and Pettis County remains very high. Flu shots are available at all Bothwell clinics, including our two walk-in clinics. Children as young as six months old can be vaccinated. Also, remember to wash your hands often with soap and water or use hand sanitizer if soap isn’t available. Cover coughs and sneezes, and stay home if you’re sick.

 As Chief Medical Officer at Bothwell Regional Health Center, Dr. Philip Fracica oversees medical operations and supports safe and high-quality patient care. Before joining Bothwell, his employment included Critical Care Medicine practice at Duke University Medical Center in Durham, North Carolina where he was an Assistant Professor of Medicine. In 2025, Dr. Fracica proudly earned a new title – grandfather.