Parental anxiety over vaccine reactions highest with first born children: study

TORONTO – A new study shows that first-born children are more likely to be taken to hospital when they have reactions to vaccinations than their younger brothers and sisters.

The study also found that the difference in hospital visits post-vaccinations was greatest in the first two sets of shots babies get, at two months and four months.

In fact, first-born children were 70 per cent more likely to be taken to hospital in the days after getting their four-month shots than their younger siblings.

The study, by Ontario researchers, can’t say for sure what is behind the higher rates of hospital visits after first-born children are vaccinated.

The authors suggest the anxiety of first-time parents could well be playing a role here.

They say it’s also possible that the first child in a family may have different responses to vaccines than younger siblings as a type of manifestation of the so-called hygiene hypothesis.

A number of studies have suggested children who have older siblings are less likely to develop asthma and allergies. It’s thought that may be because their immune systems are exposed to wider range of challenges because of their birth order.

The study, which is published in the journal PLoS One, was written by scientists from the Ottawa Hospital Research Institute, the Institute for Clinical Evaluative Sciences and the Public Health Ontario, the province’s public health agency.

The authors suggest doctors should take time to inform parents of what kind of symptoms they might see and when those symptoms are likely to appear when babies are given vaccinations.