By The Chronicle Staff

As families prepare children for another school year, vaccinations once again become part of the annual checklist for many Logan County parents.

While vaccines have protected generations of Americans from diseases that once filled hospitals and claimed thousands of lives, misinformation surrounding immunizations continues to circulate, particularly through social media and online forums.

Health professionals say many of the most common concerns are based on longstanding misconceptions rather than scientific evidence.

Those myths have persisted for decades, even as vaccines have helped eliminate or dramatically reduce diseases such as polio, measles, diphtheria and chickenpox throughout the United States.

For local families, understanding the facts can help them make informed decisions while protecting not only their own children but also neighbors, classmates and others in the community.

One of the most common misconceptions is the belief that a child’s immune system can become overwhelmed by receiving several vaccines during a single doctor’s visit.

The concern grew as childhood immunization schedules expanded and combination vaccines reduced the number of injections children receive.

According to decades of research, however, receiving multiple recommended vaccines at the same appointment has not been shown to increase the likelihood of serious adverse effects compared with receiving the vaccines separately.

Some parents choose to delay or spread out vaccinations, believing it provides an added measure of safety. Medical experts say there is no scientific evidence supporting that approach. Instead, delaying vaccinations leaves children vulnerable to illnesses during the period they remain unprotected.

That protection becomes especially important as children return to classrooms, daycare centers and extracurricular activities where infectious diseases can spread more easily.

Another misconception is that vaccines are no longer necessary because many diseases have become so rare in the United States.

Polio is one example.

Although the disease has been eliminated in the United States, it has not been eradicated worldwide. International travel means viruses can still cross borders.

If polio were reintroduced into communities with low vaccination rates, people without immunity could once again become infected.

Measles tells a similar story.

The disease was once declared eliminated in the United States, meaning it was no longer spreading continuously within the country. Yet outbreaks continue to occur after infected travelers return from countries where measles remains common and the recent outbreaks in the United States occurred among adults and children who had not been vaccinated against measles.

When vaccination rates remain high, those imported cases often stop quickly because most people are protected.

However, when vaccination coverage declines, outbreaks become more likely because the virus finds more susceptible individuals.

Health officials across Ohio have periodically monitored measles exposures linked to travel and outbreaks in other states, underscoring how quickly contagious diseases can return even after years of being uncommon.

Another point of confusion arises whenever news reports mention vaccinated individuals becoming sick during an outbreak.

Some interpret those reports as evidence that vaccines do not work. The numbers tell a different story.

Imagine an outbreak involving 500 people. If 490 have been vaccinated and only 10 have not, and the vaccine is 98 percent effective, approximately 10 vaccinated people and all 10 unvaccinated people could become ill.

At first glance, those numbers appear equal. However, only about 2 percent of the vaccinated population became sick, while every unvaccinated person contracted the disease.

Because the overwhelming majority of people are vaccinated, it is expected that a small number of breakthrough infections will occur. What matters is the dramatically lower risk faced by vaccinated individuals.

Another common claim credits cleaner water, improved sanitation and better nutrition — not vaccines — for the dramatic decline in infectious diseases.

Public health experts agree those improvements have contributed to healthier communities. Better housing, nutrition, sanitation and medical care have all reduced illness over time.

Disease records, however, show that the steepest declines often occurred only after vaccines became widely available.

Before the measles vaccine was introduced in the 1960s, hundreds of thousands of Americans contracted measles every year. Within just a few years of widespread vaccination, reported cases had fallen by more than 97 percent.

Chickenpox followed a similar pattern.

Before the chickenpox vaccine became available in 1995, roughly 4 million Americans contracted the disease each year. Less than a decade later, cases had fallen by approximately 85 percent.

Those rapid declines occurred after vaccines became available, providing strong evidence that immunization — not improved hygiene alone — was responsible for much of the reduction.

Some people also argue that it is better to acquire immunity naturally by recovering from an illness.

While natural infection can produce long-lasting immunity, physicians note that it comes with significant risks.

A measles infection can cause pneumonia, brain inflammation and even death. Brain inflammation, known as encephalitis, occurs in approximately one out of every 1,000 measles infections, and about two out of every 1,000 reported measles cases are fatal.

Serious reactions to the measles, mumps and rubella, or MMR, vaccine are exceedingly rare, occurring at a rate of roughly one in one million vaccinated individuals.

Some vaccines also provide protection that is as effective as—or even stronger than—the immunity gained through infection. Vaccines against Haemophilus influenzae type b, commonly called Hib, and tetanus are among those examples.

Vaccination also benefits people who cannot receive certain vaccines because of age or medical conditions. Infants, individuals undergoing cancer treatment and those with weakened immune systems often depend on high community vaccination rates to reduce their exposure to preventable diseases.

Medical professionals encourage residents with questions about vaccines to discuss concerns with their family physician, pediatrician, or local health department rather than relying on social media posts or unverified internet sources.

Although misconceptions continue to circulate, decades of scientific research have consistently shown that the benefits of recommended vaccines far outweigh the risks. For many diseases that younger generations have never witnessed firsthand, vaccines remain the reason those illnesses are now rare instead of routine.

The success of vaccination programs has made many once-feared diseases easy to forget. Health experts say that very success serves as a reminder that preventing disease remains far safer than treating it after it returns. ■