Why Shouldn't You Kiss Babies? Hidden Illnesses In Adults Can Make Even Healthy Babies Critically Ill

They say it takes a village to raise a child, and that village is very excited when a newborn comes into the world. Friends and relatives will flock to see the baby bearing gifts, hugs, and kisses – some of the popular ways we humans like to show our affection. Only problem is, can we unknowingly gift the child something else? Something that could make them very sick?

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That is a risk in the context of respiratory illnesses like respiratory syncytial virus (RSV). The symptoms in adults can be so mild that a person might not even realize they’re sick, but for babies, it can be a very different story.

Babies and respiratory syncytial virus (RSV)

We used to think that it was only premature babies and those with underlying disease and illness that could experience severe RSV, but now a new study is turning that idea on its head. It found that even healthy, full-term babies could become critically unwell, requiring stays in intensive care and prolonged hospitalizations.

The comprehensive study analyzed data from over 2.3 million children born in Sweden between 2001 and 2022 to look for patterns in those who required extensive intervention for RSV symptoms. A total of 1.7 percent of the children included in that dataset received a diagnosis of RSV, and 12 percent of those (representing 4,621 children) experienced severe illness.

Among the sickest babies requiring intensive care, the median age was just under two months, and most of them didn’t have any other significant health issues. The data also showed some factors associated with an increased risk of severe illness or death due to RSV, including a threefold risk for those born in the winter, or with young siblings under three years old. Meanwhile, children with a low birth weight had a fourfold risk.

“We know that several underlying diseases increase the risk of severe RSV infection, and it is these children who have so far been targeted for protection with the preventive treatment that has been available,” said study author Samuel Rhedin, resident physician at Sachs’ Children and Youth Hospital and associate professor at the Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, in a statement.

“However, the study highlights that a large proportion of children who require intensive care due to their RSV infection were previously healthy. Now that better preventive medicines are available, it is therefore positive that the definition of risk groups is being broadened to offer protection during the RSV season to previously healthy infants as well.”

The good news? There has been a fall in hospitalizations for RSV in babies since a vaccine became widely available.

Becoming an independent human after 9 months of chilling in mom’s belly is a rough ride. You come into the world with some of her immunity, but the reality is you’re still embarking on a tour of weird and worrisome illnesses that your body hasn’t met yet. As such, some doctors advise against kissing newborns due to the risk of accidentally passing on respiratory illnesses like RSV, or contagious viruses like herpes that can spread from cold sores around a person’s mouth and can cause very serious illness in young children.

For these reasons, it’s best to avoid visiting young children if you’re unwell, and as for kissing? Primrose Freestone, Associate Professor in Clinical Microbiology at the University of Leicester, wrote for The Conversation that it’s best to avoid kissing near a baby’s nose or mouth, better to aim for the back of the head or – best of all – just tickle those adorable little baby socks.

The study is published in The Lancet Regional Health - Europe.

The content of this article is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of qualified health providers with questions you may have regarding medical conditions.