We thought they were relegated to the past, but they are resurfacing with sometimes worrying incidence: measles, whooping cough, syphilis, tuberculosis, etc. Diseases of the past are returning thanks to a lack of vaccination or insufficient prevention.
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 cause 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 throughout the world for having infected artists like Baudelaire and Schubert, has long been relegated to the background of public policies, particularly in the face of the HIV epidemic. It saw its incidence jump by 110% between 2020 and 2022.
Scientists see this as a consequence of the cessation of barrier measures against the Covid pandemic, or a decline in collective immunity. But it is often insufficient vaccination coverage that is the cause.
Disease latency and mutation
« 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 yourself, Portraits of diseases of the 21st centurye century (Grasset, 2023). “ This is the epidemic genius: 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 », also notes Philippe Sansonetti, professor emeritus at the Institut Pasteur and the Collège de France. “ Syphilis, we have seen 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 says.
As with other germs, scientists see this as a consequence of the end of barrier measures against the Covid pandemic, or a drop in herd immunity. But it is often insufficient vaccination coverage that is the cause. The MMR vaccine in particular (measles-mumps-rubella) had been the victim of strong mistrust among parents due to fake news attributing cases of autism to it. Cases had soared in the 2000s that this vaccination went from “recommended” to “mandatory” for all infants in 2018 in an attempt to stem the phenomenon.
More ” there are measles in adults and adolescents among those not or poorly vaccinated (only one injection instead of the two required) », underlines Mikael Askil Guedj. For tuberculosis, which mainly affects people in very precarious situations, “ there is a vaccine, BCG, which is no longer found anywhere in pharmacies “. And who, moreover, “ does not protect very well », he adds. Concerning whooping cough, it would be necessary to “ revaccinate in adulthood, especially pregnant women “to protect future babies, because” The current vaccine does not provide lifelong protection 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.
What are the recommendations for getting rid of it?
« Some countries have a more robust vaccination policy than France », Notes Philippe Sansonetti, who expects a lot from the future digital vaccination health record. “ Today, there are gaps and confusion about the real vaccination coverage » 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 for adolescents and adults. For syphilis, “ Diagnosis is difficult, but as soon as there is doubt, serological tests must be carried out. “, adds the scientist, who also pleads for ” major information and awareness campaigns ».
