22 May 2024

Whooping cough’s deadly epidemic cycle

When the baby stopped breathing and started turning purple, I saw the real effect of this persistent disease.

I diagnosed a case of whooping cough the other week. Actually, I’ve diagnosed a couple of dozen over the course of this winter’s epidemic. In adults and children the pertussis bacterium tends to cause a debilitating paroxysmal cough that can drag on for months, trashing night after night of sleep. This latest case was in Tilly, a three-week-old baby. Babies with pertussis often don’t cough much, nor do they always make the whoop that in many children accompanies the first in-breath after a protracted paroxysm. Rather, they can simply stop breathing. Which is what Tilly did in my consulting room while I was writing my referral letter to the paediatricians.

Time has an altered quality when you’re sitting a few feet from an apnoeic baby whose face is going dusky purple. Head-in-neutral-position, mouth-over-mouth-and-nose, five-rescue-breaths… the oft-rehearsed steps for neonatal resuscitation raced through my mind, along with the sudden uncertainty over how long to give it before leaping into action. Connie, her mum, shuggled her. She stroked her cheek insistently. Dusky purple turned to blue. Then – huge relief – breathing resumed.

“What’s going to be the thrust of it?” my partner asked later, when I said I was going to write about whooping cough. I wondered about Tilly’s case being useful for raising awareness. Her dad had had a cough and cold for more than a month, her older siblings for a fortnight – in its early stages, pertussis is hard for both patients and doctors to distinguish from the usual winter viruses, and it simply hadn’t occurred to the family that they might be harbouring the bacterium they’d been hearing about in the news.

I was also tempted to write about more esoteric questions. Humans are the only species susceptible to this unusual illness; consequently, research has been hard to do. Just a couple of years ago, scientists in Japan finally developed a strain of mouse that contracts disease when exposed to the germ. This has helped to begin to unpick the array of bacterial toxins that disable our airways’ defence mechanisms, and which create the aberrant sensitisation of the cough reflex that takes so long to resolve. In time, these understandings might lead to treatments.

My partner was interested in the fact that, despite our vaccination programme, pertussis sweeps through the population every five years or so. As long ago as the 1980s, Dr Doug Jenkinson was providing clues to the explanation. A now-retired Leicestershire GP, Jenkinson assiduously documented cases of whooping cough in his practice population over decades. He discovered that immunity wanes rapidly over the five to seven years following vaccination. Epidemics such as the one we’re currently experiencing probably boost population immunity, which keeps the infection suppressed in subsequent years until that natural immunity too begins to fade.

Jenkinson is one of my medical heroes. Working single-handedly, he upended conventional wisdom. Prior to his research, it was widely assumed pertussis had been tamed, but he demonstrated how rife it was among both children and adults in epidemic years. This led to a pertussis jab being incorporated into the preschool booster campaign, and to a further booster being offered to expectant mums. This latter measure causes a surge in maternal antibodies which cross the placenta and tide the baby over with protection until they can start being vaccinated at two months old.

Like approximately half of expectant mums at the moment, Connie hadn’t taken up the booster when she was pregnant with Tilly. Happily, although Tilly needed a spell in hospital on oxygen and being fed through a nasogastric tube, she didn’t develop the severe pneumonia, hyper-viscous blood and heart failure that can prove fatal – and tragically has done for five babies this year. If this article prompts even one pregnant woman to get vaccinated who would otherwise not have done so, it will have had a good outcome.