Why is whooping cough on increase?: cases, vaccine, symptoms

Public health experts added that very low levels of exposure during the pandemic have contributed to the current outbreak.

What is 'whooping cough'?

Whooping cough is an extremely contagious bacterial infection caused by the bug, Bordetella pertussis.

The incubation period - between contracting the infection and onset of symptoms - is believed to mostly range from seven to 10 days, but can be up to three weeks.

The first signs of infection are very similar to a cold: a runny nose, sneezing, a mild cough, and sore throat. A fever is much less common.

After about week, this will progress into coughing bouts that last for a few minutes and get worse at night.

The NHS advises that this may be accompanied by a "whoop" sound - caused as the patient gasps for breath - although this may not happen in young babies.

Infants can turn blue or grey as they struggle for breath, and adults can become red in the face.

Coughing fits can result in patients bringing up thick mucus which causes them to vomit.

Symptoms are like a cold in the early stages then progress to more severe coughing fits, but adults are much less at risk from complications (Image: PA)

The history

Outbreaks of pertussis were first described in the 16th century by Guillaume de Baillou.

The organism was first isolated by Jules Bordet and Octave Gengou in 1906.

In the early 20th century, pertussis was one of the most common childhood diseases and a major cause of childhood mortality.

Before the pertussis vaccine was added the routine schedule of childhood vaccinations in Britain in the 1950s, there were around 150,000 known cases per year and more than 300 deaths.

READ MORE: 

• Dozens of GP surgeries 'at risk of closing' as Scot Govt loan scheme paused 
• Children's hospice charity needs to raise £60m 'just to stand still'

Who is most at risk?

Unvaccinated babies are at increased risk of complications such as dehydration, breathing difficulties, pneumonia, and seizures as a result of a whooping cough infection.

All five of the infants who have died in England this year due to pertussis were less than three months old.

The infection is less severe for older children and adults.

How can it be treated?

If it is diagnosed at an early stage, the infection can be treated with antibiotics.

The most effective way to prevent a whooping cough infection is through vaccination against pertussis, which is offered to all pregnant women and to infants through the "six-in-one" vaccine at eight, 12 and 16 weeks of age.

A four-in-one booster jag is then offered once children reach three years and four months of age.

Mothers vaccinated during pregnancy will pass antibodies onto newborns for the first eight weeks of their life, until they are eligible for their first round of immunisations.

Protection against pertussis is provided through the six-in-one vaccines and the four-in-one booster, which is also given to women in pregnancy (Image: PA)

How effective is the vaccine?

Studies have shown that babies born to women vaccinated at least a week before birth had a 91% reduced risk of becoming ill with whooping cough in their first weeks of life, compared to babies whose mothers had not been vaccinated.

Infants vaccinated against pertussis are estimated to have around 70% protection against infection for the first year, although this wanes over time.

Why is the current outbreak happening?

UK health officials say there have been nearly 2,800 cases of whooping cough in England between January and March this year, including five deaths in babies all under three months old.

This compares to 858 during the whole of 2023. 

Half of cases have been in under-15s.

The last peak year in England was in 2016, when there were nearly 6000 known cases.

A falling vaccine uptake among pregnant women in particular has been blamed, with coverage as low as 37% in London. In addition, fewer than 92% of babies in England had bee vaccinated before their first birthday.

Experts also say that very low numbers of infections during the pandemic mean that population-level immunity has fallen, making it easier for the bacteria to spread.

Cases of whooping cough were rising in Scotland towards the end of 2023, but data for 2024 is not yet available (Image: PHS)

What's the situation in Scotland?

Data for the first quarter of 2024 in Scotland will be published on June 4, so it is unclear exactly what the situation is here.

However, Public Health Scotland (PHS) has said that notifications of whooping cough have increased in Scotland since the beginning of the year, and it expects this to translate into an increase in confirmed cases.

The most recent available data shows that there were 73 laboratory confirmed cases of pertussis in 2023, the majority of which (56) were reported in the final quarter of the year.

The last major outbreak in Scotland occurred over two years, in 2012 and 2013, with 1,896 and 1,188 lab-confirmed cases respectively.

Prior to the pandemic, there were 533 cases in 2017; 443 in 2018; and 746 in 2019.

This fell to 198 in 2020 due to factors such as social distancing. During 2021 and 2022, there were just three and four lab-confirmed cases (although not everyone who is infected will be tested).

PHS said there have been no reported deaths from pertussis in Scotland so far this year, or since 2015.