5,854 cases of whooping cough have been recorded since the start of 2024. This is almost 12 times more than the number of cases recorded for the whole of 2023, which was only 495 cases. In 2022, according to the Pasteur Institute, 67 positive cases had been counted, 34 in 2021.
And the numbers are staggering. According to the National Reference Center for Whooping Cough (Institut Pasteur) who warned of the explosion in the number of cases this Wednesday, June 5“more than 1,400 cases confirmed by qPCR (quantitative PCR) were detected in April 2024 and more than 3,000 in May 2024”.
The epidemiology of whooping cough is cyclical, lasting 3 to 5 years. If the current resurgence is therefore not surprising, “on the other hand, it is particularly intense”.
One avenue: lower population immunity after the Covid years and barrier gestures. In 2017, the year when the number of cases of whooping cough was the highest over the period 2015 – 2023, 3,354 cases were recorded, which is much less than the figures for 2024, which are already much higher.
Strains resistant to antibiotics
Children and infants are most at risk of developing a severe form of the disease. “ In young children, notable complications are pneumonia or neurological conditions (convulsive seizures, encephalitis). In infants, whooping cough can be very serious or even fatal because it is accompanied by respiratory or multiorgan failure », underlines the Pasteur Institute.
Regarding the current epidemic outbreak, “ several cases of severe whooping cough in infantssounds were observed, requiring intensive care treatment “.
In addition, while macrolides are the antibiotics of choice for the treatment of whooping cough, two resistant strains were identified in France in February and April 2024. Until now, only one strain had been identified, in 2011. The resistance of B. pertussis to these antibiotics is very high in Asian regions (particularly in China), but remains rare outside this area. specifies the CNR.
“Great vigilance is therefore required in terms of monitoring, diagnosis and management. patient care presenting symptoms suggestive of whooping cough as well as people contacts. It is also crucial to report grouped cases or clusters to the Regional Health Agencies in charge, and to implement management measures and preventive measures », concludes the CNR in its publication.
A very contagious disease
Respiratory infection caused mainly by the bacteria Bordetella pertussis, the disease is extremely contagious. In fact, an infected person transmits the disease to 15 individuals on average, through the air, during direct contact.
In France, while the vaccine has been compulsory for infants since 1er January 2018, contamination mainly occurs from adults or adolescents – in whom boosters have not been given – to infants who have not yet been vaccinated.
As a reminder, an injection at two months and one at four months of life is mandatory, followed by a booster at 11 months, another at 6 years, then between 11 and 13 years. For adults, a booster is planned at age 25 and offered until age 39, if it has not been completed.
In order to protect newborns before the first injection, the High Authority for Health recommends vaccination in pregnant women from the second trimester of pregnancy, favoring the period between 20 and 36 weeks of amenorrhea. Objective: to increase the passive transfer of maternal antibodies across the placenta and thus ensure optimal protection of the newborn thanks to the mother’s antibodies.
Violent coughing fits
In the event of infection, the incubation phase is followed by rhinorrhea (runny nose) which can last two weeks. Then comes the paroxysmal phase characterized by a persistent cough lasting more than 7 days. Coughing fits are associated with difficult inspiratory recovery and may be followed by vomiting.
“In infants, apnea can occur, sometimes accompanied by bradycardia (heart rate below normal), or even attacks of cyanosis (bluish discoloration of the skin) during fits. In adolescents and adults, a nocturnal recrudescence is observed in the majority of cases. notes the Pasteur Institute.
Once the diagnosis is confirmed by biological tests, treatment is based on taking antibiotics from the macrolide family. The treatment is also prescribed to all people close to the patient if they have not received a booster vaccination in the last five years.
The trend of increasing cases of whooping cough is identical in several European countries, with significant epidemics notably in Croatia, Denmark and the United Kingdom. According to Public Health France, there are 40 million cases and 300,000 deaths linked to whooping cough each year worldwide.
