Cases of whooping cough “are scattered” and may be “a lot more” than those reported. Still, “it is a reason for warning, not for alarm”

Experts say that this increase in diagnoses is lower than reality, but is expected given the cyclical nature of the disease. However, they reject alarmism and call for the importance of increasing testing

The scenario that was seen in Europe is now also a reality in Portugal: the number of whooping cough diagnoses skyrocketed, going from 22 diagnosed in the entire year 2023 to 200 detected in just four months of 2024. The spike in infections It will have already passed, but the experts CNN Portugal spoke to advocate an increase in testing and the evaluation of a booster vaccine.

Carlos Robalo Cordeiro, director of the pulmonology service at the Centro Hospitalar Universitário de Coimbra (CHUC), believes that these 200 cases are “dispersed”, ruling out the idea that an outbreak could be involved. Manuel Ferreira de Magalhães, pediatrician at Centro Materno-Infantil do Norte and Hospital Lusíadas Porto, also validates the idea that cases are spread across the country and clarifies that this increase in diagnoses “was expected”.

“The bacteria that causes whooping cough – Bordetella pertussis – historically comes in outbreaks every three to five years”, continues the doctor. Although he is unable to specify the number of cases that have already passed through his hands in these first months of the year, he recognizes that, “yes, there has been an increase”, whether in “inpatient, outpatient or urgent care”, but is immediately quick to say that “the worst is over” and that the situation will “now stagnate”.

The news of the 200 cases of whooping cough in the first four months of 2024 arrived this Wednesday through the Observer. Of these two hundred cases, 86% of diagnoses were made in children, of which 21% in children between 10 and 13 years old and 20% in babies under one year old. CNN Portugal tried to obtain data on the location of cases from the Directorate-General for Health, which said it only had available the information sent to newsrooms on the total number of cases.

Number of cases is “much higher”

For pediatrician Manuel Ferreira de Magalhães, who also provides consultations at Hospital Lusíadas, the numbers that the DGS presented “are underreported”, explaining that “the majority” of people infected with the bacteria and with symptoms of whooping cough “do not do the test”, as the disease can be mild in adolescents and young adults. “The number is much higher,” he continues.

Hugo Rodrigues, pediatrician at the Local Health Unit of Alto Minho, and who is also part of the Multicenter Clinical-Epidemiological Study of Whooping Cough in Pediatric Ages in Portugal, reinforces the expected side of this increase in cases, not only due to the nature of the bacteria, but as it is “a widespread European phenomenon”, in which the greater circulation of people – including from countries with lower vaccination rates – “always justifies” the greater circulation and spread of infectious agents.

The doctor from Viana do Castelo, who is also the author of the page Pediatrician for Everyone, believes that this phenomenon “is underdiagnosed” and that it would be interesting to increase testing and, above all, access to testing, since there are hospitals where “research for this microorganism is not carried out” or where results are only obtained days later. “And before that we already had to medicate”, he says.

Carlos Robalo Cordeiro reveals that in Coimbra he has not noticed an increase in cases of whooping cough, but says that just this Thursday he met with a doctor from a family health unit in the region who is accompanying a foreign family, living in Portugal, in which all elements were diagnosed with whooping cough. “There are only three, four cases here,” he says, without giving details, but noting that it is likely that there are infected households.

“There is a certain fluctuation in this disease, it is endemic and its prevalence fluctuates a lot. We can go years without prevalence and then there will be a peak, as is happening this year. It is normal that [estes aumentos de casos] happen at a certain frequency and not every year”, continues Carlos Robalo Cordeiro, also director of the Faculty of Medicine of the University of Coimbra (FMUC), adding that increasing testing could be important at this stage. “I don’t know if it wouldn’t be worth testing more, that way we could reach more diagnoses and promote greater prevention” of the spread of the disease, says the doctor.

Carlos Robalo Cordeiro also considers that this increase in cases “has clinical importance, especially for children who have not yet been vaccinated”, but rules out a panic scenario. “It is a reason for warning, not for alarm”, he says, saying that, for this very reason, the DGS issued recommendations to health entities for the “triple need” that this scenario brings: “testing suspicious situations as much as possible, obligatorily reporting and promote vaccination, particularly of pregnant women”.

Vaccination booster could be a brake

Vaccination is the greatest protective shield against this infectious disease and vaccination coverage in Portugal is quite satisfactory, experts say. According to the 2024 Annual Vaccination Summary Report, with data referring to 2023, vaccination coverage of the 5th dose of combined vaccine (which includes immunity against whooping cough) reached 95% and it is estimated that 85% of eligible pregnant women have been vaccinated. Even so, this high rate of vaccinated children and pregnant women was not enough to stop an increase in cases, which pediatrician Manuel Ferreira Magalhães says is expected taking into account the European scenario and the fact that this infectious disease, like so many others, give rise to cyclical outbreaks. The European Center for Disease Prevention and Control (ECDC) itself explains that “larger epidemics are expected every three to five years, even with high vaccination coverage”.

Vaccination against whooping cough occurs five times during childhood. The first dose is administered at two months of age (in a triple-action vaccine against diphtheria, tetanus and whooping cough), the second at four months (as part of the pentavalent vaccine), the third at six months (in the hexavalent vaccine), the fourth at 18 months (again included in the pentavalent vaccine) and the fifth at five years of age. Then, with each pregnancy, women are given a single dose of the tetanus, diphtheria and whooping cough (Tdpa) vaccine, in reduced doses.

Some European countries carry out a booster vaccination against whooping cough and pediatrician Hugo Rodrigues says that it could be important to invest in a booster, particularly because a good part of the cases now diagnosed are in children between 10 and 13 years old, who, despite presenting mild symptoms of the disease, are “transmission vehicles” for the most vulnerable. “It would be important to stop the transmission chains”, he says.

Manuel Ferreira de Magalhães says that the adoption of this scheme in Portugal would have to be evaluated, especially because, he explains, “the big problem with whooping cough is in young babies and the elderly” and, therefore, “if it happens, reinforcements should be more in these age groups.”