New research from RCSI University of Medicine and Health Sciences and Children’s Health Ireland (CHI) shows babies born during the earliest lockdown in 2020 had a very low rate of antibiotic use and reduced hospital admissions. The study also found that immunisation among these infants was above the national average.

The research found that the babies had very low rates of COVID-19 infection by six months of age, suggesting lockdown was an effective public health strategy in protecting one of society's most vulnerable groups.

The CORAL study, with initial findings published in the journal Paediatric Allergy and Immunology, is collecting blood and stool samples from 360 babies to investigate the impact of COVID-19 lockdown on their coronavirus exposure and routine healthcare access in Ireland.

Principal investigator, Professor Jonathan Hourihane from CHI at Temple Street and RCSI's Department of Paediatrics, said: "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."

In total, only four participating children contracted COVID-19 during the first six months – two who had positive tests in the community and two other babies having unexpectedly positive COVID-19 results when attending their appointments in CHI at Connolly.

Professor Hourihane added: "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. The children will have allergy testing at one and two years of age and we can then examine the relationships between their microbiome and allergy outcomes. 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. It is co-funded by the Children’s Health Foundation and the Clemens von Pirquet Foundation, a European allergy charity.