Battle to halt rise in whooping cough cases claiming children’s lives
Doctors and officials in the Philippines are linking low immunisation rates, possibly caused by past vaccine fearmongering, to a recent rise in whooping cough cases that have led to at least 49 deaths among young children this year.
Dr Albert Domingo, an official in the Philippines’ Department of Health, said 862 cases of whooping cough, or pertussis, had been recorded in the first three months of 2024.
A highly contagious yet preventable respiratory tract infection, pertussis is easily spread through sneezing or coughing and can cause serious illness in people of all ages – but is most dangerous for babies.
The World Health Organization only recommends administering the first diphtheria-tetanus-pertussis vaccine to children at six weeks of age, leaving very young infants particularly vulnerable to infection.
But in the Philippines’ recent whooping-cough outbreak, the worst-hit age group – with 34 deaths – was infants aged six weeks to four months, Domingo said.
Among those who have died from complications related to the infection this year were also 13 babies under six weeks of age, a five-month-old infant and a four-year-old child.
Domingo said most regions in the Philippines had reported pertussis cases, with 158 in Metro Manila alone – and the outbreak was expected to spread. Nearly 30 times the number of cases were recorded in the first three months as the same period last year, when the health department tallied just 28 infections.
Antibiotics can be used to treat whooping cough, but the infection is often mistaken for the common cold as symptoms can appear mild at first.
Dr Maria Liza Zabala, a paediatric pulmonologist and former associate clinical professor at the University of the Philippines, said her private practice in Bataan, a province a few hours away from Manila, had seen an influx of patients with symptoms including chronic coughs, colds, fever, and difficulty breathing.
“Although clinical manifestations of pertussis vary with age, there should be a high index of suspicion [among doctors]. Recognition of the disease can be done based on history and signs and symptoms,” Zabala said.
“Most infants with whooping cough do not cough at all,” she said. “They may present with atypical clinical presentations and may often be unrecognised, leading to serious complications such as seizures, pulmonary hypertension, and respiratory problems like pneumonia … Their symptoms could mimic those of a common cold throughout the duration of their illness, not just in the initial stages. These issues can pose a life-threatening risk.”
Like other doctors on social media, Zabala has called for more vaccinations and booster shots to curb the spread of infection. The outbreak could have been caused by “missed jabs or vaccinations, especially during and after the Covid pandemic”, she said. “Unvaccinated or incompletely vaccinated children or adults act as reservoirs of infection. Likewise, booster doses should be given to prevent waning immunity from the disease, but they are often missed.”
The Philippine Department of Health offers three doses of the pentavalent vaccine for free, beginning at six weeks. This vaccine series, completed at 10 to 14 weeks of age, protects infants from diphtheria, pertussis, tetanus, Hemophilus influenza type b and hepatitis B. But health officials say low immunisation rates among children in recent years have curtailed widespread protection against these diseases. Free vaccinations are not available to older children and adults in the Philippines.
The World Health Organization says about 95 per cent of any given population must be vaccinated to achieve herd immunity against diseases, but Domingo said just 62.3 per cent of children in the Philippines were considered “fully immunised” as of last year. “The pertussis – and even measles – outbreaks have been linked to decreased vaccination rates during the pandemic because of the lockdown or decreased movement of the population. This is not just a problem seen in the Philippines, but also worldwide,” he said.
However, according to Unicef, the UN children’s agency, immunisation rates had been steadily declining even before the pandemic. From 2019 to 2022, there were 1 million children in the Philippines who had received zero doses of vaccine.
Janette Garin, a congresswoman, doctor and former Philippine health secretary, has attributed vaccine hesitancy among Filipinos to an earlier controversy surrounding the
Dengvaxia vaccine, which led many parents to avoid government immunisation programmes.
The deaths of 14 Filipino children were linked to the dengue vaccine, produced by pharmaceutical company Sanofi Pasteur, in 2017 by Philippine Chief Public Attorney Persida Acosta, who filed criminal charges against Garin and other officials based on her office’s autopsy findings.
Medical groups such as Doctors for Truth and Public Welfare slammed that conclusion as baseless and urged an end to the autopsies. Their call was based on the findings of pathologists at the Philippine General Hospital, who concluded that only three deaths had a causal link to the vaccine.
Domingo attributed the vaccine hesitancy to “misinformation and a lack of awareness” about the availability of free vaccinations in village health centres.