The quest for a longer-lasting whooping cough vaccine
This 19th-Century killer is making a comeback – and with protection from the whooping cough vaccine waning over time, the hunt is on for something longer-lasting.
Whooping cough wasn't really on Juliet Lautenbach's radar. During her pregnancy and her daughter's childhood, both had received free public vaccines against whooping cough along with all the other standard immunisations.
But five years after giving birth, Lautenbach was working in an open-plan office with a colleague who was coughing a lot. The coworker revealed that she had whooping cough, and Lautenbach realised that both her persistent cough and her daughter's could be related. Lautenbach doesn't blame that colleague, but notes that "for every person who walks around with whooping cough, there's somebody sitting within two desks of them in a closed office space who has a young child who's vulnerable".
Lautenbach, a civil servant and fantasy author based in Canberra, Australia, still remembers how intense the four weeks of coughing were. "Even as an adult, I found it compulsive." It felt like she had pulled muscles along her ribs, she says. But it was much worse for her daughter, who had asthma and was prone to illness. The five-year-old coughed for six months, making the characteristic whoop sound – which the disease is named after – when she gasped for breath. On one occasion when they were racing to the hospital, Lautenbach had to pull over the car every 10 minutes to give her daughter her inhaler and stop her from turning blue.
Thankfully Lautenbach's daughter survived that bout of whooping cough, as well as a later one as a teenager. The vaccine may well have saved her life. But it wasn't perfect, Lautenbach says she "didn’t realise until much later that the whooping cough one actually became less and less effective" over time.
Two generations of vaccines
Whooping cough is a highly contagious respiratory disease spread by the bacteria Bordetella pertussis (pertussis is another name for the illness). Pertussis, which typically resurges cyclically, is currently on the rise in many countries, after a quiet period during the Covid-19 pandemic. In the European Economic Area, more cases were reported between January and March 2024 than during all of 2023. In many countries, the number of pregnant women being vaccinated against pertussis has been declining. In the UK, 58.6% of pregnant women received the vaccine between 2023 and 2024, compared to 70.5% between 2019 and 2020.
If there's one infected person in a room, within an hour roughly 90% of susceptible people there may contract the disease
Pertussis was part of the first-ever combination vaccine, DTP, which was first released in 1948 and is still in use today – it covers diphtheria, tetanus and pertussis. There are now several other options for combination vaccines including pertussis, most recently a six-in-one vaccine. Vaccines have made a tremendous difference to the severity of the illness. Before vaccination, on average, 10% of children with whooping cough died from it. Both infections and deaths dropped rapidly with the advent of vaccines. Whooping cough remains one of the most common causes of death that could have been prevented with vaccines. Vaccine effectiveness at preventing the disease typically ranges between 79% and 84%, with about 91% effectiveness in preventing hospitalisation.
Daniela Hozbor, a bacterial vaccine researcher at the Institute of Biology and Molecular Biology at La Plata National University, Argentina (IBBM UNLP-CONICET), explains just how easily pertussis spreads: if there's one infected person in a room, within an hour roughly 90% of susceptible people there may contract the disease. That's why it's so important to prevent pertussis with vaccination rather than simply relying on antibiotics afterward, which won't stop the contagion, Hozbor says. She is so passionate about communicating the importance of vaccination that she includes a reminder and a link to vaccination schedules in her email signature.
The world essentially has a two-tier system for pertussis vaccines. The first-generation whole-cell vaccines can have more serious effects like seizure, but are more effective and cheaper to produce. These whole-cell vaccines are used in many low and middle-income countries.
Second-generation acellular vaccines are administered in wealthier countries. These are safer but are based on just a handful of antigens – substances which can elicit an immune response – unlike the hundreds or thousands of antigens involved in whole-cell vaccines, explains Camille Locht, the research director of the French National Institute of Health and Medical Research (Inserm).
Locht has worked on multiple generations of whooping cough vaccines. As a junior scientist at a pharmaceutical company in the 1980s, researching acellular pertussis vaccines, he was convinced that including a toxin produced by the bacteria would help generate a potent immune response, he says. However, the acellular vaccines developed involved inactivating the toxin chemically, which he speculates might have destroyed some protective portions of the toxin.
When Locht left pharma for academia, he had a niggling feeling that the story of pertussis wasn't finished. Indeed, "what we didn't know at the time was that the vaccine didn't prevent infection," though it was very effective at preventing disease and reducing mortality from whooping cough.