Whooping cough cases outbreak reported around the world

China, Australia, Spain among countries with high number of patients with the respiratory infection

By Seema Prasad
Published: Friday 12 April 2024
Whooping cough can affect people of all ages when immunity wanes over time. Photo for representation: iStock

Whooping cough, a highly contagious respiratory illness also known as pertussis, is making a concerning comeback across the globe. Outbreaks are being reported in numerous countries, raising concerns about vaccine efficacy and the vulnerability of young children.

China has reported a more than 20-fold increase in whooping cough cases in January and February compared to the same period last year. After confirming 32,380 cases and 13 deaths, Chinese authorities warned that it is a major cause of mortality among infants and young children globally.

However, whooping cough can affect people of all ages when immunity wanes over time. The increasing number of cases has been attributed to the weakening of the vaccine's long-term effects in China. 

Read more: Beyond vaccine hesitancy: Understanding systemic barriers to getting vaccinated

According to an expert cited by Chinese tabloid newspaper Global Times, the diphtheria, tetanus and pertussis (DTP) vaccine used in the country faces production and quality control challenges unlike vaccines manufactured in developed countries.

The disease experiences a cyclical rise every three to five years, but incidences have been growing for more than twenty years. Another potential reason researchers are considering behind the rising incidences of pertussis over the last two decades is the impact of outdoor air pollution in China.

According to a 2023 study by Chinese scientists published in the journal BMC Public Health, a short-term high monthly carbon dioxide and ozone exposure, with a 10 micrograms per cubic metre increase in nitrogen dioxide (NO2) and ozone corresponded with surges. 

Read more: Childhood immunisation begins to pick up post-pandemic, finds UN data

“One possible mechanism of NO2 and other air pollutants was that, regardless of the duration of exposure, high levels of NO2 can irritate airways and increase susceptibility to respiratory infections. Compared with adults, children are at a higher risk because they breathe at higher rates and spend more time outdoors and their lungs and immune systems are immature,” the paper said.

The bordetella pertussis bacteria that causes whooping cough also appears to have mutated, particularly in Australia. The country is facing its worst outbreak since 2013, with 2,799 cases recorded in the first three months of 2024.

A strain of the virus that was pertactin-deficient appeared to have become the dominant strain by 2017 in Australia. Pertactin is a key protein targeted by the vaccine, reported The Conversation, a network of nonprofit media outlets.

Read more: COVID-19 fallout: 25 million children missed routine vaccinations last year

The resurgence of whooping cough worldwide also includes several European nations. In contrast to the 1,200 cases discovered throughout 2023 in Spain, the country experienced an outbreak of 8,200 cases by March 2024. 

Similarly, the Czech Republic has reported a record number of cases after more than 70 years, with over 6,300 this year. Post the COVID-19 pandemic, a World Health Organization (WHO) spokesperson told television news network Euronews that only 50 per cent of the countries in the European region have been able to vaccinate 90 per cent of their population.

According WHO, in 2022, 20.5 million children missed out on one or more doses of their DTP vaccines.

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