Parents are reluctant to vaccinate their children for many reasons, but one of the more persistent arguments has been a fear of 'overwhelming' the immune system.

There's no shortage of research on the topic showing that there's no reason for concern, so it should come as no surprise that this latest research backs it up. The only question is, will it make much of a difference?

Many new parents can sympathise with the trepidation – your baby seems fragile, and every added vaccination in a growing schedule leaves you questioning the risks.

It's even harder to see the big picture when we don't have the constant shocking reminders of history's epidemics in front of us.

In countries like the US, this reluctance leads to somewhere between 10 and 15 percent of infants under the age of 2 having their vaccinations delayed or refused.

A new study conducted by a team of researchers in the US took a somewhat practical approach to the question of whether vaccines can compromise an infant's immune system. They looked into the rates of infectious diseases we don't vaccinate against.

By examining the medical records of 944 infants aged between 2 and 4, the scientists determined whether exposure to a relatively large number of antigens made a young child more likely to contract some other kind of infectious agent.

The answer is a clear 'no'. They found absolutely no significant difference between infants who had cumulative exposure to antigens - that is, a lot of vaccines - and those who didn't.

From a theoretical point of view, such a system shock of antigens would make little sense – newborns are inundated with a rich variety of microbes as they leave the womb.

The handful of antigens making up the vaccination schedule is a relative drop in the bucket compared with the vast zoo of microbes the immune system has to sort out in those first few years of life.

In simple terms, rather than acting as an army fighting off infection, our infant immune system is adept at diplomatically dealing with a near countless number of potential allies and villains.

But failure to imagine makes for poor evidence, so researchers have hunted for a number of potential ways that vaccines might cause more damage than they prevent.

In 2002, a report by the Immunization Safety Review Committee from the US Institute of Medicine summarised hypothetical mechanisms that would – if true – explain such an overwhelming biological response.

A study conducted several years later by a team of Danish researchers put these suggestions to the test using a database of more than 800,000 children, finding vaccines did not raise their risk of hospitalisation from non-targeted diseases.

Scientifically, there's no such thing as 'case closed'. But the burden of proof required from those who still maintain the current schedule of vaccinations somehow reduces the efficiency of our immune system is now higher than ever.

Not that we can imagine studies like this one making a significant impact, unfortunately.

Accepting the results of data such as this relies on trusting its source, which doesn't come naturally to many people with diverse beliefs and ideologies.

Finding the right approach, such as appealing to shared values in liberty or in purity, might be more the way to go.

There is hope, with a study conducted last year indicating the numbers of folks who hesitate or refuse to vaccinate is no longer increasing.

There's no doubt vaccination will remain a politically contentious issue for many years to come, and more studies are always welcome.

But by now we can confidently say the only thing overwhelming about vaccines is the evidence that they're a whole lot safer than the alternative.

This research was published in JAMA.