Gut microbiome and allergies in newborns positively impacted by Covid lockdowns

5th March 2024

The lockdowns imposed during the Covid-19 pandemic positively impacted the gut microbiome and subsequent allergy development of babies born during this time, a new study has revealed.

Researchers working in Ireland found significant differences in the gut microbiome development of babies born during lockdown periods compared to pre-pandemic babies, including lower than expected rates of allergenic conditions.

The findings, published in the journal Allergy, highlighted how environmental exposures and dietary components significantly impacted microbiota community assembly.

And they were the first to demonstrate gut health benefits arising from the unique lockdown environment, including lower rates of infection and consequent antibiotic use and increased duration of breastfeeding.

The researchers from the Royal College of Surgeons in Ireland (RCSI), Children’s Health Ireland and APC Microbiome Ireland at University College Cork collected faecal samples from 351 babies born during the first three months of the pandemic. The samples were collected at six months (n = 351) then at 12 (n = 343) using 16S sequencing.

Skin prick testing (SPT) was performed at 12 (n = 343) and 24 (n = 320) months of age, accompanied by atopic dermatitis and food allergy assessments.

In infants with atopic dermatitis, a Scoring Atopic Dermatitis (ScorAD) was calculated at 12 and 24 months and a total and objective ScorAD recorded. SPT was completed for the three most common food allergens (peanut, egg and milk) and aeroallergens (house dust mite, grass pollen and cat dander) in all infants.

Online questionnaires were used to gather epidemiological information about the babies’ diet, home environment, health and healthcare utilisation and allergic diseases, including suspected adverse food reactions and atopic dermatitis. 

The pandemic-born babies were part of the CORAL (Impact of CoronaVirus Pandemic on Allergic and Autoimmune Dysregulation in Infants Born During Lockdown) project, and the results were compared with samples from pre-pandemic cohorts of babies.

Professor Liam O’Mahony, from the University of Cork and principal investigator at APC, said: ‘We took the opportunity to study gut microbiome development in infants raised during the early Covid-19 era when strict social distancing restrictions were in place, as the complexity of early life exposures was reduced and this facilitated a more accurate identification of the key early life exposures.

‘Prior to this study, it has been difficult to fully determine the relative contribution of these multiple environmental exposures and dietary factors on early life microbiome development.’

Significant differences existed in the gut microbiomes of the two cohorts. Pandemic-born babies showed a higher relative abundance of bifidobacteria at both six and 12 months, which was associated with a reduced likelihood of atopic dermatitis and positive SPT results.

Infants with elevated Bifidobacterium levels at six months of age typically exhibited fewer allergic symptoms or a lower risk of developing allergic diseases than those with lower levels of this bacteria.

The increase in bifidobacteria was linked to reduced external exposure, an increase in breastfeeding and a decrease in antibiotics during lockdown.

Social distancing was associated with delayed acquisition of horizontally transmitted spore-forming bacteria. Bacteria such as the environmentally transmitted Clostridia were found to have lower concentrations at both six and 12 months in the pandemic cohort compared with the pre-pandemic babies, correlating with the microbial exposure index.

Levels of atopic dermatitis observed in the study were not higher than expected levels. Specifically, at 12 months of age, atopic dermatitis was observed in 24.8% of participants (n=343), and at 24 months, it was observed in 19.5% (n=320).

Levels of food allergen and airborne sensitisation were also within the expected range for this age group, with SPT positivity at 7.4% at 12 months and 12.0% at 24 months.

The prevalence of allergen sensitisation, food allergy, and atopic dermatitis did not increase over pre-pandemic levels, suggesting the lockdown period did not lead to a higher incidence of allergic conditions.

Joint senior author of the study Professor Jonathan Hourihane and head of paediatrics at RCSI, added: ‘This study offers a new perspective on the impact of social isolation in early life on the gut microbiome.

‘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.’

The researchers hope to re-examine the children born during the pandemic when they are five years old to investigate whether there are longer-term health benefits arising from the early differences seen in the gut microbiome.

In August 2023, researchers found that delays in gut microbiome maturation in young children were uniformly associated with distinct allergic diagnoses at five years of age.

Acute asthma admissions sharply declined during lockdowns as air quality improved, study reveals

9th February 2024

Reduced pollution levels and better air quality during the Covid-19 pandemic lockdowns strongly correlated with lower rates of acute asthma care provision, according to new research led by the University of Birmingham.

The retrospective time-series study, published in the BMJ Open, investigated the link between acute asthma hospital admissions and specific air pollutant levels in four Oxford postcodes during the national lockdowns of March to June and November to December 2020.

For adult residents, acute asthma admissions fell from 78 per 100,000 residents in 2015-19, to 46 per 100,000 residents in 2020 – a reduction of 41%.

This reduction in acute asthma care coincided with levels of air pollution falling significantly. Different pollutants dropped by 18-33% when compared to average values for the previous five-year period.

For example, nitrogen dioxide (NO₂) reduced by 26.7% from a 2015-19 average of 14.6 μg m-3 to 10.7 μg m-3 in 2020.

Fine particulate matter (PM_2.5) saw a reduction of 33.5% from 10.1 μg m-3 in 2015-19 to 6.7 μg m-3 in 2020, and PM₁₀ reduced by 18.6% from 13.2 μg m-3 in 2015-19 to 10.8 μg m-3 in 2020.

‘Large-scale measures to improve air quality have potential to protect vulnerable people living with chronic asthma in urban areas,’ the authors concluded.

Commenting on the ‘unique situation’ of temporary air quality improvement, Dr Suzanne Bartington, clinical associate professor of environmental health at the University of Birmingham and lead author of the study, said: ‘The results of air pollution levels falling may have had an impact on the number of severe asthma cases that need acute hospital care, with 41% fewer hospital stays compared to the previous five-year average.

‘Furthermore, we also identified a 4% increase in risk of asthma hospital admissions for every 1 μg m-3 increase in mean monthly NO₂, and an approximately 3% increase in risk for every 1 μg m-3 increase in mean monthly PM2.5 levels.

‘This is an important study to help us better understand how demand for NHS inpatient care may change when air quality is improved.’

The research team was supported by the University of Oxford, Oxfordshire County and City Councils and the then Oxfordshire Clinical Commissioning Group.

Commenting on the results, Councillor Nathan Ley, Oxfordshire County Council’s cabinet member for public health, inequalities and community safety, said: ‘We must now use what we have learned, thanks to this research with our partners, to improve our environment, in line with the Clean Air Strategy which we launched last year.

‘Elevated levels of NO₂, PM_2.5 and PM₁₀ contribute towards heart disease, chronic lung disease, cancers, preterm births, and many other avoidable events. The vision of Oxfordshire County Council to tackle this issue remains clear. We must continue to use all the tools at our disposal to lead the country, clean up our air and save lives.’

Earlier this week, the European Respiratory Society (ERS) warned of rising respiratory diseases, such as asthma, as well as premature death without urgent action on air quality.

This followed the ERS consensus statement on climate change and respiratory health, published in September 2023, which highlighted the damaging effects of air pollution on health and global warming.

Allergic rhinitis symptoms worsened during COVID-19 lockdown

17th February 2022

Allergic rhinitis symptoms worsened for nearly 40% of patients during the pandemic possibly due to increased exposure to indoor allergens

Allergic rhinitis (AR) symptoms were worse for some patients during the COVID-19 lockdown and this was most likely due to increased exposure to indoor allergens according to a study by researchers from Fundacion Santa Fe de Bogotá, Columbia.

Allergic rhinitis is characterised by one or more symptoms, including sneezing, itching, nasal congestion and rhinorrhoea and affects 15 to 25% of the population. Allergy avoidance is an effective management strategy for those with seasonal allergic rhinitis and hayfever sufferers are usually symptom-free outside the pollen season. In contrast, allergy avoidance for individuals with house dust mite-sensitive AR is more difficult given that the mites are present in the home. In fact, an Italian study has shown that the first COVID-19 lockdown ordered by the Italian government, negatively influenced the clinical history of patients with dust mite allergy. In terms of management, allergen-specific immunotherapy (allergen-SIT) is the only known treatment able to alter the natural course of allergic rhinitis.

But to what extent did the COVID-19 national lockdown and the abrupt cessation of SIT impact on symptom control in patients with AR was the subject of the present study by the Columbian researchers. They performed an observational study between March and May 2020 to assess any changes in AR symptoms in patients with a clinical diagnosis of AR and who were treated with monthly depot SIT injections for at least 6 months. The team used a visual analogue scale (VAS) from 0 (no symptoms) to 10 (severe symptoms) to assess the main AR symptoms including nasal obstruction, pruritus, rhinorrhoea and ocular symptoms. In addition, trained researchers used a sociodemographic questionnaire to collect further information on participants, for instance, age, education level, income, floor material in the household, number of household members etc.

Allergic rhinitis and symptom control

A total of 318 individuals with a mean age of 18.9 years (55.1% female) were included in the analysis. The median number of immunotherapy doses before the lockdown was 11 with a median of 3 doses missed during isolation.

Overall, 38.4% reported that their symptoms worsened during the lockdown period and this was apparent for all AR symptoms. For example, for nasal obstruction, 69.6% stated that their symptoms worsened compared to 30.4% who reported that their symptoms improved or remained the same. A pre-post mean difference in the VAS of 0.5 was found for nasal obstruction (p = 0.01) and pruritus (p < 0.001), a 0.7 difference for rhinorrhoea (p < 0.001) and 0.8 for ocular symptoms (p < 0.001).

Factors associated with a reduction in the final VAS scores were the presence of dogs and cats in the house, atopic dermatitis, lower levels of education and a lower number of immunotherapy doses prior to the lockdown.

The authors concluded that the worsening of AR symptoms during the COVID-19 lockdown was likely to be attributable to a higher exposure to indoor allergens and the interruption of immunotherapy, highlighting the importance of environmental factors in the pathogenesis of the disease.

Citation
Pérez-Herrera LC et al. Impact of the COVID‐19 national lockdown in the allergic rhinitis symptoms in patients treated with immunotherapy at two allergy referral centers in Bogotá, Colombia Laryngoscope Investig. Otolaryngol 2022

Latest REACT-1 data show no decline in COVID-19 prevalence in England

25th January 2021

REACT-1 study is an ongoing COVID-19 prevalence study in England and round 8a suggests there was no evidence of a decline in the prevalence of COVID-19 during the third national lockdown.

The Real-time Assessment of Community Transmission (REACT-1) is a longitudinal study of the community prevalence of COVID-19, led by a team from Imperial College, London. The study regularly reports on the prevalence of COVID-19 collected from a random sample of more than 120,000 people in England, identified from national health service records linked to a patient’s GP. Invited participants, who vary in age from 5 years to over 65, are sent a nasopharyngeal swab kit for home testing and which is then collected and analysed for COVID-19. The study has been collecting data since June 2020 and provides an important snapshot of the prevalence of COVID-19 in the community.

Findings

The REACT-1 (8a) covers the period 6-15 January 2021. Researchers found a total of 1962 positive swabs from 142,909 individuals giving a weighted prevalence of 1.58% (95% CI 1.49-1.68%). Interestingly, they note that this represents the highest prevalence since the study began in May 2020, when the prevalence was 0.16%. Moreover, it is more than 50% higher than round 7 (the previous data collection period), between November to December 2020). However, using a growth model, the team could not find any evidence of either a growth or decay in prevalence and estimated the transmission rate, R to be 1.04. In analysing mobility data from the Facebook app, the team found a decreased activity at the end of December 2020 that began to rise again in January 2021. As a result, they speculated that this increased activity might have caused the rise in cases. Across the country, the prevalence more than doubled in the London area from last round 7 (1.21%-2.47%) and in the East of England (0.59%-1.74%). However, infection rates decreased in Yorkshire and The Humber and remained broadly similar to round 7 in the East Midlands. The age-related prevalence showed an increase among those aged 18 to 24 (0.99%-2.51%) and among those aged 65 years and over (0.41%-0.94%). In discussing their findings, the authors noted that there was no continued decline in prevalence during the third national lockdown but rather a slight initial decline followed by a plateau or possible increase. They also cautioned that if rates do not fall there will be an increase in hospitalisations, which will negatively impact on healthcare delivery.

Citation
REACT-1 round 8 interim report; SARS-CoV-2 prevalence during the initial stages of the third national lockdown in England.