PETALING JAYA — It begins innocuously enough - a runny nose, a mild fever, the kind of cold any new parent might dismiss. But in a baby under five months old, whooping cough or pertussis, is something else entirely.
The coughing fits come in violent, uncontrollable bursts, robbing the infant of air until the lips and skin turn blue and for dozens of Malaysian families each year, it ends in tragedy.
In 2023, 43 deaths among infants below five months old due to pertussis were reported in Malaysia, nearly half of all pertussis cases that year were in babies too young to have completed their vaccination course.
It is a statistic that haunts paediatricians and one that the Health Ministry has moved to address with a policy shift that took effect last year.
Since 2025, Malaysia has offered free Tdap immunisation to pregnant women at government clinics between 28 and 32 weeks of pregnancy, joining more than 50 countries that have adopted the strategy to protect newborns before they can protect themselves.
The logic of the intervention is elegantly simple. Babies only receive their first DTaP vaccine dose at two months of age and are not fully protected until six months.
That four-month window of vulnerability is where pertussis strikes hardest.
By vaccinating the mother during pregnancy, her antibodies cross the placenta and are transferred to the baby, providing a shield from the moment of birth.
Consultant Obstetrician and Gynaecologist and President Perinatal Society Malaysia Prof Dr Jamiyah Hassan emphasised that this is why Tdap immunisation during pregnancy was introduced to fill the gap.
"When pregnant mothers receive their Tdap immunisation, their bodies produce protective antibodies that are passed to their babies through the placenta.
"This gives the baby protection from birth, during those first critical months," she said.
The numbers bear out the effectiveness of the approach. Tdap immunisation during pregnancy reduces the risk of pertussis in infants by up to 93 per cent and can prevent up to 95 per cent of pertussis-related deaths.
One of the most insidious aspects of pertussis is that the greatest danger to a newborn often comes from within the family home.
The bacterium responsible lives in the nose, mouth and throat of infected individuals.
Older children and adults frequently carry the infection with only mild symptoms or none at all, unknowingly passing it to a baby with no defence.
Consultant Paediatrician and Technical Committee chairman of the Immunise4Life programme Prof Datuk Dr Zulkifli Ismail the infection can be passed on by parents, siblings, caregivers, even elderly grandparents and healthcare providers.
"The people closest to a newborn in its first weeks of life are precisely the vector the disease exploits.
"The bacterium resides in the mouth, nose and throat of infected individuals. Older children and adults may have only mild symptoms or none at all – putting vulnerable young infants at risk," he said.
Beyond pertussis, the Tdap vaccine also protects against tetanus and diphtheria. Dr Jamiyah is firm on the safety question, a common concern among expectant mothers.
"Tdap vaccine has been proven to be safe for both mother and baby. It has been carefully studied and is widely used around the world, showing no increased risk to the pregnancy. While some mothers might experience mild side effects, these are generally well-tolerated."
The vaccine is provided free at government clinics and is also available for a fee at university hospitals, private hospitals and private clinics.
Early uptake has been described as encouraging, with specialists crediting growing public awareness and widening trust in maternal immunisation.
The 100-day cough earned its name because that is, historically, how long its victims were condemned to suffer.
For a newborn with no defence, those days may never come at all. The vaccine, its advocates argue, is a gift given before the baby has taken its first breath.