The study highlights a shift in the disease pattern, with a rise in cases caused by meningococcal serogroups that were previously less common before the pandemic.” Since the pandemic, there has actually been a particular revival in meningococcal serogroups W and Y compared with the other serogroups,” continues Ala-Eddine Deghmane, co-lead author of the research study and Deputy Director of the National Reference Center for Meningococci at the Institut Pasteur. In other words, the meningococcal bacterial strains accountable for IMD today are different from those that were flowing before the pandemic, and they target various age groups. The influenza virus creates a beneficial context for the development of meningococcal germs. “If the quadrivalent meningococcal vaccine for serogroups A, Y, c, and w were to be recommended for teenagers, it would supply direct security for them and also indirect protection for other classifications of the population,” explains Ala-Eddine Deghmane.
A research study by the Institut Pasteur revealed a noteworthy increase in intrusive meningococcal disease in France post-COVID-19, with a shift in impacted age and bacterial pressures. This renewal underscores the importance of adapting vaccine techniques in response to developing public health difficulties.
A group of researchers from the Institut Pasteur made use of the National Reference Center for Meningococcis database to evaluate the development of intrusive meningococcal disease in France from 2015 to 2022. Their findings, which were recently published in the Journal of Infection and Public Health, show a significant renewal of the disease following the relaxation of COVID-19 restrictions.
The study highlights a shift in the disease pattern, with an increase in cases triggered by meningococcal serogroups that were previously less common before the pandemic. Especially, there has been a boost in infections amongst individuals aged 16 to 24. The insights gained from this research study are expected to inform changes in vaccination strategies to combat this potentially fatal disease.
Impact of COVID-19 Measures on IMD
Throughout the COVID-19 epidemic, health and hygiene measures like wearing masks and social distancing had a favorable effect on respiratory infections. This held true for intrusive meningococcal illness (IMD), with the variety of infections falling by more than 75% in 2020 and 2021. What would occur at the end of the pandemic, when the protective steps were reduced?
” During the COVID-19 pandemic, two theories emerged,” describes Muhamed-Kheir Taha, co-lead author of the study, Head of the Invasive Bacterial Infections Unit and Director of the National Reference Center for Meningococci at the Institut Pasteur. “The very first was that this favorable result would last which meningococci would stop circulating over the long term. The second was that there would be a fast revival in bacterial activity amongst an ignorant population which had not enter into contact with the bacteria for a long time.”
Neisseria meningitidis germs (in red) binding to the surface of an epithelial cell (nucleus in blue) contaminated with influenza infection (viral neuraminidase in green). Influenza infection helps with diplococci binding to the cell surface area. Fluorescence microscopy. Credit: Institut Pasteur/ Muhamed-Kheir Taha Invasive Bacterial Infections Unit
A team of researchers from the Institut Pasteur for that reason chose to carry out a detailed research study of the development of the disease between 2015 and 2022, and they validated the second hypothesis.
Analysis of IMD Cases Post-Pandemic
Utilizing samples from the National Reference Center for Meningococci, which has recorded all cases of IMD in France since 1980, the researchers had the ability to look back over the pandemic duration. The first observation was clear.
” There was an unmatched renewal in invasive meningococcal illness in fall 2022, and now, in autumn 2023, the number of cases is greater than in the pre-COVID-19 period,” details Samy Taha, first author of the study and a scientist in the Institut Pasteurs Invasive Bacterial Infections Unit.
Compared with an overall of 298 cases recorded in between January and September 2019, 421 cases have already been recorded between January and September 2023– a rise of 36%, although the winter peak has not yet arrived. The figure for the exact same duration in 2021 was 53 cases.
There are 2 main explanations for this: basic resistance was weaker due to the fact that stress were circulating less, but there was also a decline in vaccination, with meningitis C vaccination falling by 20% throughout the very first lockdown, for instance. So the population has actually become ignorant when faced with bacteria that are constantly developing– the bacterial genome is highly variable.
Modifications in Meningococcal Strains and Age Groups Affected
” Since the pandemic, there has actually been a specific resurgence in meningococcal serogroups W and Y compared with the other serogroups,” continues Ala-Eddine Deghmane, co-lead author of the study and Deputy Director of the National Reference Center for Meningococci at the Institut Pasteur. In other words, the meningococcal bacterial stress accountable for IMD today are various from those that were circulating before the pandemic, and they target various age groups.
Potential Increase in Cases and Vaccine Strategy
This renewal in meningitis could gather momentum in the coming months with the result of seasonal influenza. The influenza infection produces a favorable context for the development of meningococcal germs. All mass gatherings can be a risk element for infection in basic, and specifically for IMD.
In France, just meningitis C vaccination is necessary; vaccination for meningitis B is simply recommended in infants. There are not yet any recommendations in the general population for serogroups Y and W. The researchers are therefore in contact with the French National Authority for Health to assist adjust the future vaccine method. “If the quadrivalent meningococcal vaccine for serogroups A, C, w, and y were to be recommended for teenagers, it would supply direct defense for them and also indirect security for other classifications of the population,” explains Ala-Eddine Deghmane. Teenagers are the main healthy providers of meningococci. “We must bear in mind that without treatment, the death rate for bacterial meningitis is virtually 100%. Even with correct treatment, there is still a 10% death rate. Vaccine avoidance is important,” concludes Muhamed-Kheir Taha.
Recommendation: “The fast rebound of invasive meningococcal illness in France at the end of 2022” by Samy Taha, Eva Hong, Mélanie Denizon, Michael Falguières, Aude Terrade, Ala-Eddine Deghmane and Muhamed-Kheir Taha, 12 October 2023, Journal of Infection and Public Health.DOI: 10.1016/ j.jiph.2023.10.001.