Forgotten diseases that come back
Whooping cough is making a comeback in France. Nearly 6,000 cases of this respiratory infection were recorded in the first five months of the year, five times more than in 2023.
The number of measles cases is exploding. In 2023, 117 cases (including 31 imported) were reported in France, compared to 15 in 2022. This highly contagious viral disease is often benign but can lead to serious respiratory and neurological complications, sometimes fatal in babies.
Tuberculosis, while remaining at a low level, has seen a rebound in cases in France in 2023 after three years of health crisis, with 4,728 reported cases. Transmitted through the air, it is a highly contagious bacterial infection that most often affects the lungs, but can spread to the brain.
Syphilis, a sexually transmitted infection infamous worldwide for having infected artists such as Baudelaire and Schubert, has long been relegated to the background of public policies, particularly in the face of the HIV epidemic. Its incidence has jumped by 110% between 2020 and 2022.
Had they really disappeared?
“Never really, but they have transformed, spaced out over time,” underlines Mikael Askil Guedj, doctor of medical sciences and eye surgeon, who looked at all the diseases of the century in a book “Doctors in spite of you, Portraits diseases of the 21st century” (Grasset, 2023). “This is the genius of epidemics: there are cycles of a few years, sometimes a few decades, where diseases are forgotten, mutate a little, then reappear without warning.”
These diseases “have always been latent,” notes Philippe Sansonetti, professor emeritus at the Pasteur Institute and the Collège de France.
“Syphilis, we saw it flare up with AIDS and then fall again at the same time as prevention measures; tuberculosis had declined sufficiently for vaccination to be stopped; As for measles and whooping cough, we live with irregular outbreaks,” he explains.
How can we explain their current resurgence?
As with other germs, scientists see this as a consequence of the cessation of barrier measures against the Covid-19 pandemic, or a decline in collective immunity. But it is often insufficient vaccination coverage that is to blame.
The MMR vaccine (measles-mumps-rubella) in particular had been the victim of strong mistrust among parents due to fake news attributing cases of autism to it. Cases had increased so much in the 2000s that this vaccination went from recommended to mandatory for all infants in 2018 in an attempt to stem the phenomenon. But “there are adult and adolescent measles cases among those who are not or poorly vaccinated (a single injection instead of the two mandatory ones)”, Mikael Askil Guedj points out.
For tuberculosis, which mainly affects people in very precarious situations, “there is a vaccine, BCG, which is no longer found anywhere in pharmacies”. And which, moreover, “does not protect very well”, he adds.
Concerning whooping cough, it would be necessary to “re-vaccinate in adulthood, in particular pregnant women” to protect future babies, because “the current vaccine does not protect for life against infection”, underlines Philippe Sansonetti.
As for syphilis, its return can be explained by the reduced use of condoms, since antiretrovirals have reduced the fear of AIDS. “Many people carry it without knowing it, and continue to spread syphilis because the first symptoms are quite discreet or poorly identified,” adds Dr. Guedj.
Recommendations for getting rid of it
“Some countries have a more robust vaccination policy than France,” notes Philippe Sansonetti, who has high expectations for the future digital vaccination health record. “Today, there are gaps and uncertainty about the actual vaccination coverage” of adults, he notes.
Without necessarily advocating compulsory vaccination for all, as is the case in pediatrics, the researcher questions the implementation of a better vaccination policy among adolescents and adults.
