In its latest epidemiological update, Public Health France takes stock of cases of whooping cough in 2024. It appears that the number of reports notified to the ARS La Réunion has seen a substantial increase with 64 reports. For comparison in 2023, only 4 reports had been recorded. Children and infants are most affected by this significant increase. We publish the press release below. (Photo: www.imazpress.com)
In 2024, the various whooping cough surveillance indicators monitored by Public Health France La Réunion show the following trends:
– Reports to the ARS
An increase in cases of whooping cough reported to the ARS La Réunion, of which 27% of reports concerned infants (children under 1 year old)
– At the hospital
An increase in visits to emergency departments for the main reason of whooping cough compared to previous years and mainly affecting children under 1 year old (48%).
– Biological data in town and hospital
Read also – Vaccination in Reunion: the population is vaccinating more but not yet enough
An increase in positive PCRs and the positivity rate in the 2nd half of 2024 and, more particularly among young children
Methodology
Regional surveillance has been set up to describe and characterize the temporal trends and the health impact of the disease on the Reunion Island territory.
To do this, Public Health France La Réunion analyzed regional data from several sources.
Data from reports notified by ARS La Réunion
This is a system for monitoring reports of whooping cough cases established by the Health Alert and Management Monitoring Unit (CVAGS) of ARS La Réunion.
Reporting data allows us to track trends in the general population.
Emergency department visit data – OSCOUR® Network
Individual data on visits to the emergency room and hospitalizations for the main reason of whooping cough are recorded daily by the emergency services of Reunion Island.
These data contain demographic information (age, sex), administrative (date of entry and exit from the emergency room, etc.) and medical (medical diagnoses
main and associated coded according to the international classification of diseases 10th revision).
This surveillance makes it possible to characterize the profile of pertussis cases.
Biological data – 3Labos Network
The 3labos device allows the automated reporting to Public Health France of specialized medical biology analysis data from Cerba and Eurofins-Biomnis laboratories for samples taken by laboratories in town or in hospitals, for surveillance purposes or in the alert and emergency framework.
Read also – 19 cases of whooping cough recorded since the start of the year
3Labos data for Reunion Island made it possible to have the results of PCR tests for whooping cough to monitor the dynamics
circulation of the bacterium Bordella pertussis.
Hospital biological data
These biological data in a hospital environment allow us to have the results of positive PCRs for the Bordella pertussis bacteria to describe and monitor the temporal trends of the disease, in particular its health impact.
Results
Reports
In 2024, the number of reports of whooping cough cases notified to the ARS La Réunion saw a substantial increase with 64 reports. For comparison in 2023, only 4 reports were recorded by the CVAGS.
From a temporal point of view, 55% of reports (n = 35) were recorded in the last quarter of 2024 with a peak in December with the reporting of 14 cases.
The median age of reported cases is 15 years old [min : 4 semaines – max : 91 ans]. Considering the distribution by age group: 53% of reports concerned people aged 15 and over, 27% infants (children under 1 year old) and 20% for the 1-14 year old age group.
Hospital monitoring indicators
Data from emergency visits
The year 2024 was marked by an increase in visits to the emergency room for reasons of whooping cough with a total of 25, 8 of which were hospitalized.
Read also – Cases of whooping cough are increasing in Reunion
This increase in visits to emergency rooms is the most significant in 10 years, reflecting active circulation
of whooping cough on Reunion Island.
From a temporal point of view, emergency visits only concerned the 2nd half of 2024, including 68% (n=17) in the last quarter of 2024.
Concerning the distribution by age group of visits to the emergency room, children under 1 year old constitute the population at risk in 2024 with 48% (n=12/25) of visits to the emergency room.
Over the period from 2013 to 2024, children under 1 year old represented nearly 5 out of 10 emergency room visits.
Biological data
At the hospital
In 2024, hospital biological data indicated an increase in the number of positive PCR tests for pertussis with a total of 37 compared to previous years, confirming the resurgence and circulation of the disease in Reunion even if the number of cases remains weak.
Since January 1, 2024, biological data has reported a total of 37 positive PCR searches for Bordella Pertussis with a positivity rate which remains very low (1.2%) but has been increasing since the start of 2024.
In the last quarter of 2024, 22 positive PCRs for pertussis were identified, representing a positivity rate of 2.4%.
In town medicine
In 2024, data from the 3Labos network showed an increase in the number of pertussis PCR tests in the second half of 2024, illustrating active circulation of the disease. From July to December 2024, 95 positive PCRs were recorded with an annual positivity rate of 9.2%.
The month of August 2024 was characterized by the maximum positivity rate at 11.6% with 24 positive PCRs.
The distribution of PCRs by age group in 2024 showed that young children aged 6 to 10 were the most affected (28.6%) followed by adolescents and young adults aged 11 to 24 (22.7 %).
Prevention measures
Whooping cough vaccination for pregnant women.
Public Health recalls the importance of vaccination recommendations for pregnant women.
In the context of the whooping cough epidemic which has raged this year 2024 and to protect the youngest infants for whom the disease is particularly serious, vaccination against whooping cough of young mothers remains essential and the best possible protection.
Indeed, infants can only benefit from sufficient protection after a complete vaccination schedule at 2, 4 and 11 months. There vaccination is therefore recommended for mothers during pregnancy and each pregnancy.
This vaccination of pregnant women, which is recommended from the second trimester of pregnancy and at the latest one month before childbirth, recommended since 2022 in France, is the most effective measure for protect the infant from birth thanks to transplacental transfer
maternal antibodies.
The High Authority of Health recommended on July 22, 2024 that any person in close contact with a newborn and/or infant under 6 months of age in a family setting receive a booster, if their last whooping cough vaccination was more than 5 years ago. Click here.
Recently, Epi-Phare published the results of a national study carried out using SNDS data on pertussis vaccination coverage (CV) of pregnant women in France (whose pregnancy began between August 2023 and March 2024), the characteristics of these pregnant women and the factors influencing vaccination.
These results show that pertussis vaccination coverage in this population was 63.2% with more than 90% of women having been vaccinated between the 18th and 34th week of pregnancy.
They also show that the vaccination rate has experienced a sharp increase in France each year since 2021. According to this study, the vaccination rates were respectively around 41%, 12%, and 2% for the years 2023, 2022, and 2021 .
Conclusions
As in France, Reunion Island experienced a higher level of circulation of the bacteria compared to previous years.
Both hospital and biological surveillance indicators indicated a clear increase in the number of cases in the population in particular, from the second half of 2024.
Children and particularly infants (children under 1 year old) constituted a significant proportion of whooping cough cases.
Therefore, the protection of newborns and infants must be a priority. It is based on the passive immunization strategy induced by vaccination of the future mother during her pregnancy (transplacental passage of antibodies) favoring the period from the 5th to the 8th and for each pregnancy.
In addition, the protection of young children requires a compulsory primary vaccination strategy, namely:
– 1st dose at 2 months
– 2nd dose at 4 months
– 1st booster at 11 months
Finally, the recommendations issued this summer by the High Authority of Health (HAS) on July 22, 2024 and the High Council of Public Health (HCSP) on August 12, 2024, on people in close contact with a newborn and/or infant less than 6 months and prevention in people at high risk and at risk of severe form of the disease is maintained.
SCHEDULE THE VACCINATION
INFANTS AND CHILDREN (UP TO 13 YEARS OLD):
– Compulsory primary vaccination at the age of 2 months, 4 months and first booster at 11 months (3 doses).
-Following boosters at 6 years old and between 11 and 13 years old.
ADULTS:
– Reminder for mothers with every pregnancy, regardless of the mother’s age
– Booster at age 25: 1 dose of combined vaccine containing whooping cough vaccine (except in the case of whooping cough vaccination less than 5 years old). If this booster was not done at age 25, it can be done anytime between ages 26 and 39.
– At the age of 45 and 65 in a professional context.
– Possible reminders as part of the cocooning strategy, to be done on a case-by-case basis.
Whooping cough is not a notifiable disease but must be reported to the ARS Indian Ocean health monitoring and emergencies platform in 2 specific situations:
– Occurrence of grouped cases (from 2 cases).
– Reporting of nosocomial infections (prevent EOH and E-Sin reporting)
The minimum number of cases to intervene is 1 case. Given the current context of whooping cough circulation in Reunion Island and insufficient vaccination coverage, particularly for boosters, any case, even isolated, must be reported by health professionals to:
ARS La Réunion Tel: 02 62 93 94 15 Fax: 02 62 93 94 56
Email: [email protected]
ARS, Public Health France, Whooping Cough, epidemiological surveillance
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