The Impact of Lockdown on Allergies in Infants

When COVID-19 began invading our communities, we knew it would change things. How much things would change, we didn’t know. Now we are beginning to see the effects that the presence of COVID-19 has had on our lives. A recently published study looked into the impact that COVID-19 lockdowns had on allergies in infants and the results were pretty surprising. The Impact of Lockdown on Allergies in Infants

The Point of the Study

As microbiome research develops we’ve learned that overuse of sterilizing agents can negatively impact the gut microbiome. The gut microbiome requires exposure to microbes to boost the richness and diversity of microorganisms within the gut. When we aren’t exposed to enough microbes it can negatively affect the composition of the microbiome.

The negative effects of low microdiversity often look like inflammation in the intestines or throughout the body leading to a higher risk of allergies and atopic dermatitis — especially in infants and young children.

Social distancing and increased use of sterilization products like hand sanitizer and surface cleaners could have impacted babies born during this time. Taking these precautions to prevent the spread of COVID-19 put up an interesting barrier for what is thought to be necessary exposure for the developing infant microbiome.

So the point of this study was to see how these precautions affected infants born during lockdowns with a special focus on their gut microbiomes and allergies.

Study Set Up

It is quite sterile in the womb. Much of the environmental exposure of infants happens in the first 6-12 months. They become exposed through their food, being around other people, and coming into contact with different microbes (healthy or pathogenic). This boosts their immunity and provides the infant microbiomes with new strains to work with.

The study looked at infants born in Ireland from March through May 2020. This was when the pandemic first began and restrictions were the most strict.

During this time, 3773 babies were born. After excluding children who fit into the following categories:

Pre-birth PCR-proven SARS-CoV-2 infection in a parent or co-dwelling person
Intravenous antibiotics in the neonatal period
Multiple births
Major congenital anomaly

Infants included fell into the following categories:

55% male : 45% female
96% Caucasian
46% were the firstborn in their family
65% were born vaginally

360 children ended up being included in the study. Data was collected at 6, 12, and 24 months for the following categories:

COVID-19 antibody screening (baseline and 6 months)
Detailed epidemiological information (collected every 6 months)
Dietary questionnaire and food frequency data (done at 12 months)
Home environment (including household size, siblings, rural or urban, type of house, type of childcare (in or outside the home), pets, and if any smokers live in the home)
Infant health status (including antibiotic use, infections, contact with people who had or were exposed to COVID-19, vaccinations, etc.)
Allergic signs or symptoms (food-related or atopic dermatitis)
Atopic dermatitis testing (done at 12 and 24 months)
Skin prick testing for allergies (done at 12 and 24 months
Stool samples (taken at 6 and 12 months)

All of this data was collected and compared to see what bacterial strains were likely derived from what exposures. It helped researchers to see how the microbiome grew for each infant with their exposures.

This also helped to show what contributed to the development of or prevented allergies or atopic dermatitis in infants.

The Results: The Impact of Lockdown on Allergies in Infants

Some of the initial data from the study was interesting. We saw that children weren’t exposed to many pathogens by their first birthdays.

Only 4.7% had COVID-19 antibodies by 12 months old
Only 17% required antibiotic use in their first year. This was drastically different from the 80% of pre-pandemic babies that had to use antibiotics in their first year.
25% of the babies had not met another child their age by their first birthday

Studies have shown that mode of delivery (C-section or vaginal) and diet highly determine the constitution of the gut microbiome in babies. This study showed some interesting results. By 6 months of age, only 3% of the gut microbiome was determined by the mode of delivery. This is a relatively small percentage considering the impact other studies have stressed.

Age determined 26% of the composition which was more impactful than how the baby was born. By 12 months of age, the differences between delivery modes were undetectable between infants.

As for antibiotic use, while there were changes to the gut microbiomes (as we would expect) they didn’t remain statistically significant by 12 months of age. Continual use of antibiotics may have a different effect that builds upon the initial changes to make them remain. However, minimal use of antibiotics (when necessary) can be corrected over time.

The most interesting results were that diet was the main determinant of the child’s gut microbiome makeup. Breastfeeding determined a large portion of the infant microbiome, especially at 6 and 12 months. Between 6 and 12 months of age, dietary changes and exposure to other people became more important.

There was a noted delay in the presence of spore-forming bacteria in the pandemic babies compared to pre-pandemic. These are important bacterial types that can regulate the gut microbiome. By 12 months of age they had normalized but being around other people and in new places was what provided the infant gut microbiome with this important type of bacteria.

As for the allergies, the breakdown is as follows:

By 12 months, 87 infants had atopic dermatitis
By 24 months, 68 infants had atopic dermatitis. Atopic dermatitis risk was more highly associated with infants whose parents also had it and living in a home with smokers.
Skin prick test resulted in 26 positive results at 12 months and 35 at 24 months.
IgE-mediated food allergies were at 15 for 12 months and 5 for 24 months.
Non-IgE food reactions were 27 at 12 months and 7 at 24 months.

None of these quantities were abnormal for the expected predictions from years past.

The Verdict

While COVID-19 lockdowns did have effects on the infant microbiome, they weren’t as drastic as expected. They also did not have the negative impact researchers thought it would. This is great news!

Any negative impacts from COVID-19 lockdowns were able to be remedied by a healthy diet containing breastmilk, fruits, nuts, seeds, and healthy oils. Thus putting a large significance on the developing infant microbiome on diet.

Exposure to environmental factors helps to contribute to a healthy microbiome, but those strains are able to be contracted as the infant ages and through diet and healthy lifestyle choices. Keeping infants away from smoke and smokers has more impact on reducing allergies in infants than environmental exposure.

So if you’re a new mom or your baby was born during the COVID-19 lockdowns, don’t worry. Your baby will get what they need for a healthy life. Just continue feeding them healthy, whole foods and keeping them in healthy spaces.

Read this article for suggestions on how to keep your child’s gut healthy!

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