A new study has shown that babies born during Ireland’s earliest lockdown in 2020 had a very low rate of antibiotic use.

Hospital admissions among this group were also reduced, while rates of immunisation were above the national average.

The CORAL study was undertaken by researchers at the RCSI University of Medicine and Health Sciences and Children’s Health Ireland (CHI). It involved the collection of blood and stool samples from 360 babies in order to investigate the impact of lockdown on Covid-19 exposure and routine healthcare access in Ireland.

It found that the babies had very low rates of Covid infection by six months of age, suggesting that lockdown had been an effective public health strategy for this vulnerable group.

Altogether, just four participating children contracted Covid-19 during the first six months - two who had tested positive in the community and two who unexpectedly tested positive when attending their appointment in CHI at Connolly Hospital.

“We set up the study to see if lockdown might support the so-called hygiene hypothesis - suggesting that the way we live so cleanly nowadays increases allergy rates. We wanted to investigate how this might be further exaggerated by lockdown and reduced human contact.

“Initial results of the study show very low rates of antibiotic use and reduced hospital admissions for our participants. We also saw higher than average rates of immunisation in babies when it was thought uptake would actually decline due to fears about going to healthcare facilities,” explained the study’s principal investigator, Prof Jonathan Hourihane of CHI Temple Street and the RCSI.

He noted that the CORAL study is ongoing.

“We will continue to study the stool microbiome and allergy rate results, but the indication of low Covid infection rates, low antibiotic use and low hospital attendance suggest we are on the right track with fewer infections circulating,” he said.

He explained that the children involved will have allergy testing at one and two years of age and this will allow the researchers to examine the relationships between their microbiome and allergy outcomes.

He added that it is “reassuring that this population of infants born during lockdown have received routine healthcare as normal”.

The study is a joint initiative with APC Centre in University College Cork, with babies recruited from the Rotunda and Coombe hospitals in Dublin. The initial findings are published in the journal, Paediatric Allergy and Immunology, and can be viewed here.