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News of the week August 28 – September 3, 2023:
The diversity of the gut microbiome in infants, reduced during the COVID-19 pandemic. What is the impact on development?
A recent study conducted by a team of researchers in developmental psychology from New York University shows the impact of the COVID-19 pandemic on the gut microbiome of infants. The results, published in the journal Scientific Reportsindicate that infants who spent a significant portion of their first year of life during the pandemic had reduced gut bacterial diversity compared to infants born before the pandemic.
The infants also showed a lower amount of Pasteurellaceae and Haemophilus bacteria, which are commonly found in the human body. Alteration of the gut microbiome during this period can have a lasting impact on children’s growth and development.
Changes in gut microbiota could be linked to social changes brought about by the COVID-19 pandemic. Factors such as increased time spent at home, reduced interaction with other children due to limited access to kindergarten, increased environmental hygiene measures, changes in diet and breastfeeding practices, as well as increased stress among caregivers could contribute to the changes the intestinal microbiome.
The study compared faecal samples from two groups of 12-month-old infants in New York. One group consisted of infants whose samples were collected before the pandemic (34 infants), while the other group had samples collected between March and December 2020 (20 infants).
New mechanisms explain how the immune response to influenza virus is triggered in the lungs
Research at Trinity College Dublin shows new mechanisms by which the influenza virus is detected by human lung cells, which may have therapeutic implications.
Influenza viruses target respiratory epithelial cells to replicate, where they cause cellular damage. These cell types are essential in triggering the antiviral immune response.
In the new study viral RNA and influenza viruses have been found to stimulate two different molecular pathways in which specific proteins trigger chain reactions that lead to the formation of pores in the epithelial cell membrane, a mechanism in which two key proteins are involved: gasdermin D and gasdermin E. These the pores allow the release of cytokines that stimulate the immune response and also cause cell death, which prevents the spread of the virus.
At a later stage, gasdermin pore formation was suppressed, and the result was an increase in the replication rate of influenza viruses.
Influenza viruses cause epidemics annually that endanger 3 to 5 million people with serious illness and cause 290,000 to 650,000 deaths worldwide.
Anticipating the evolution of an epidemic possible with the help of artificial intelligence, from a small amount of data
FALLS4 is a model that uses machine learning to predict the evolution of an epidemic using only limited data about infections. SPADE4 was tested on both simulated epidemics and real data from the fifth wave of the Covid-19 pandemic in Canada and was able to predict the evolution of infection outbreaks. The study was conducted at University of Waterloo.
When an epidemic occurs, whether new infections like Covid-19 or existing ones like Ebola, the ability to predict the course of the disease is critical to public health decision-making.
Traditionally, epidemiologists have had to build and use complex models to understand the evolution of epidemics, models that have many drawbacks, according to the study authors. These require complex demographic information that is often not available early in an epidemic. Even when this detailed information is available, models may not accurately reflect population complexity or disease dynamics. SPADE4 addresses these limitations and enables adaptation of strategies to combat emerging infections.
How did Omicron evolve and why do new variants spread more easily?
In a study published in the journal Nature, the peculiarities of the Omicron variants are explained and why they spread much faster. BQ.11 and XBB.1.5, have an increased ability to bind to receptors on host cells and can avoid antibodies generated by previous infections and those obtained after vaccination.
Since its emergence in Wuhan, China in 2019, the SARS-CoV-2 virus has undergone a continuous process of evolution. Some of the generated variants had low spread while others, such as those derived from Omicron, emerged as strains with increased infectivity.
The Omicron variants, initially the BA.1 and later followed by variants such as the BA.2, BA.4, BA.5, BQ.1.1 and its XBB derivatives, including the XBB.1 and XBB.1.5, attracted attention not only due to increased capacity spread, but also due to its ability to reinfect people who had previously been infected by other strains and to avoid the immunity conferred by previous vaccines.
Although the neutralizing capacity of the antibodies generated by the first SARS-CoV-2 variants was reduced, the maintenance of the activity of a particular type of antibody, S309, which targets a component of the spike protein, was observed to remain relatively constant as the variants evolved. .
The authors also presented an explanation why people vaccinated or who went through infection with the first variants are not totally protected from the new variants. This phenomenon is called immune imprinting – when the body is faced with a new infection with a similar virus, instead of producing a targeted response, all the initial types of antibodies are produced.
Therefore, vaccines against the new variants should not contain components from the previous ones because it would favor the phenomenon of immune imprinting and lead to a weaker protection.
Updated Comirnaty vaccine recommended for authorization in the EU
European Medicines Agency (EMA) recommended authorization of the Comirnaty vaccine adapted for the XBB.1.5 variant on August 30. According to the EMA and the European Center for Disease Prevention and Control (ECDC), adults and children from 5 years of age who require vaccination should receive a single dose, regardless of their history of vaccination against COVID-19.
Children aged 6 months to 4 years may receive one or three doses, depending on vaccination or infection history.
In deciding to recommend authorisation, the CHMP considered all available data on Comirnaty and the other adapted vaccines, including data on safety, efficacy and immunogenicity (how well they stimulate immune responses). In addition, the Committee evaluated new laboratory data showing a strong response of the adapted vaccine against the XBB.1.5 strain and related strains of the virus that cause COVID-19.
Next, the EMA will send the CHMP recommendation to the European Commission for a decision valid throughout the European Union.
2023-09-04 18:06:58
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