What is pertussis and should South Africans be concerned?

There has been an increase in the number of pertussis cases reported in SA from May to September, says the National Institute for Communicable Diseases.

Cape Town – Pertussis, also known as whooping cough, is a highly infectious disease that affects the respiratory tract. It is caused by the bacterium Bordetella pertussis.

According to the National Institute for Communicable Diseases (NICD), from the beginning of 2022 to September 15, 147 pertussis cases were reported with a steady increase in the number of cases reported since May and a sharp increase from July (23 cases) through August (33 cases) and September (53 cases).

Pertussis, also known as whooping cough, is a highly contagious respiratory infection caused by the bacterium Bordetella pertussis. In 2018, there were more than 151 000 cases of pertussis globally.

Pertussis spreads easily from person to person mainly through droplets produced by coughing or sneezing. The disease is most dangerous in infants, and is a significant cause of disease and death in this age group.

The first symptoms generally appear 7 to 10 days after infection. They include a mild fever, runny nose and cough, which in typical cases gradually develops into a hacking cough followed by whooping (hence the common name of whooping cough). Pneumonia is a relatively common complication, and seizures and brain disease occur rarely.

Of the 147 cases, 77% were children less than 5 years of age (113/147), of which 89 (79%) were children less than 3 months.

The NICD said the majority of cases, 42% (62/147), were from the Western Cape (Figure 2).

In July and August 2022, the cases reported were evenly distributed across provinces and in keeping with numbers reported before Covid-19, while in September 2022 the majority of cases, 79% (38/48), were reported from the Western Cape and numbers were higher than those reported from this province pre-Covid-19.

How it spreads

Pertussis spreads easily from person to person mainly through droplets produced by coughing or sneezing. The disease is most dangerous in infants, and is a significant cause of disease and death in this age group, according to the World Health Organization.

The first symptoms generally appear seven to 10 days after infection.

They include a mild fever, runny nose and cough, which in typical cases gradually develops into a hacking cough followed by whooping (hence the common name of whooping cough).

Pneumonia is a relatively common complication, and seizures and brain disease occur rarely.

Very few pertussis cases were reported through the notifiable medical conditions (NMC) surveillance system in 2020 and 2021 in South Africa, probably as a result of decreased transmission related to non-pharmaceutical interventions to prevent the spread of Sars-CoV-2, said the NCID.

Suspected cases of pertussis:

– Any person with a cough lasting ≥14 days (cough illness of any duration for children aged <1 year), without an apparent cause,

– plus one or more of the following: paroxysms of coughing, inspiratory whoop, post-tussive vomiting, apnoea

– cyanosis; for infants aged <1 year only) OR any person in whom a clinician suspects pertussis infection

Probable case of pertussis:

– A suspected case with signs and symptoms consistent with pertussis and an epidemiological link by contact with a laboratory-confirmed case of pertussis in the 21 days before symptom onset.

Confirmed case of pertussis:

– A suspected case with signs and symptoms consistent with pertussis AND laboratory confirmation (isolation of B. pertussis from a respiratory specimen OR PCR-positive respiratory specimen OR B. pertussis-specific antibody response).

IOL