Covid-19 pandemic babies ‘more likely to have healthier guts, to suffer fewer food allergies’

Irish researchers found lower rates of infection and longer periods of breastfeeding during lockdowns had a positive effect on babies’ gut development

‘Pandemic babies’ – babies born during the Covid-19 pandemic lockdowns – are more likely to have healthier guts and suffer from fewer food allergies because of the “unique environment of lockdown”, new research has found.

A new study published in the European Allergy medical journal revealed lower rates of infection, which usually lead to use of antibiotics, and longer periods of breastfeeding during lockdowns positively impacted babies’ gut microbiome development during the pandemic.

Researchers found newborns who arrived during the Covid-19 lockdowns developed more beneficial microbes, which play a role in protecting against allergic diseases, after birth from their mothers.

Our gut microbiome, an ecosystem of microbes that live in our digestive tract, plays an essential role in human health.


Only 17 per cent of the babies included in the study, who were born during the first three months of the pandemic in 2020, required an antibiotic during the first year of their life. This compares to 80 per cent of babies in the UK requiring an antibiotic in the first 12 months of life, based on a pre-pandemic study.

Breastfeeding was “significantly positively” associated with the babies’ healthier guts, while plant-based foods such as beans, nuts and seeds were also found to have positive effects on the babies’ gut development.

The research also found babies born during lockdown had lower-than-expected rates of allergic conditions, such as food allergies, with “significant differences” in the microbiome development of babies born during lockdown periods when compared to pre-pandemic babies.

A median number of three people had kissed the babies featured in the study, which featured some 350 infants, during their first six months of life, including parents, while 25 per cent had not met a child their own age by their first birthday, according to the new research.

“We speculate that the immature immune system of young infants cannot safely respond to the massive microbial diversity they face in modern densely populated cities,” notes the report.

However, it concludes that gut development is only “partially dependent” on exposure to humans, animals or environments, and that the transmission of maternal microbes at birth, breastfeeding and avoidance of infections to reduce the need for antibiotics “may be critical”.

The authors propose that “modern lifestyle factors, including Cesarean-section birth and lack of breastfeeding that fail to support vertical microbiota transmission”, and frequent antibiotic use, may be “jointly responsible with other unidentified factors for the increase in allergic diseases”.

The study was carried out by analysing fecal samples from 351 babies born during the first three months of the pandemic, compared to samples from pre-pandemic babies. Online questionnaires for parents were used to collect information on diet, home environment and health, while further stool samples were collected at six, 12 and 24 months, and allergy testing was performed at 12 and 24 months.

It acknowledges the study “has limitations” given that those involved came from families with “high levels of parental income and education” and was “undertaken under the extraordinary social circumstances of pandemic control measures”.

The research was conducted by experts from RCSI University of Medicine and Health Sciences, Children’s Health Ireland and APC Microbiome Ireland based in University College Cork.

Prof Jonathan Hourihane, head of the Department of Paediatrics at RCSI and a consultant paediatrician at Children’s Health Ireland Temple Street, who co-authored the study, said researchers planned to re-examine the children involved at five years of age to examine any “longer-term impacts of these interesting changes in early gut microbiome”.

“This study offers a new perspective on the impact of social isolation in early life on the gut microbiome,” he said. “Notably, the lower allergy rates among newborns during the lockdown could highlight the impact of lifestyle and environmental factors, such as frequent antibiotic use, on the rise of allergic diseases.”

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Sorcha Pollak

Sorcha Pollak

Sorcha Pollak is an Irish Times reporter and cohost of the In the News podcast