THE HSE HAS again warned the public to be vigilant against a continuing outbreak of whooping cough in Ireland.

The HPSC (Health Protection Surveillance Centre) has recorded that up to 7 December, a total of 444 cases of whooping cough (pertussis) were notified to the centre. This is double the number of cases recorded over the same time period last year, up to the start of December (217). The total number of cases for 2011 was 229 cases, which in itself was double those in 2010 (114).

The outbreak is “of concern” the HSE told TheJournal.ie this week, and it said it was continuing to provide updates and information to health professionals in a bid to stem the spread of the disease.

Of particular concern is the increase in cases among very young children, especially babies. The highest number of cases recorded this year has been among the 0-4 year age group – they accounted for 229, or 52 per cent, of the cases. Babies from newborn to just five months old accounted for over half, 142, of those cases again.

The severity of the disease is also a worry: by the end of the first week in December, almost one-third of reported cases of whooping cough had seen the sufferer hospitalised. (That was in 131 or 30 per cent of cases). Of those hospitalised, 80 per cent were those babies aged five months or under. Tragically, two infants have died this year in Ireland from causes linked to the whooping cough.

The HSPC says that the number of cases recorded in young children is partly due to the fact that they will automatically require hospitalisation for this very serious disease and “it is normal for samples to be obtained and sent to the laboratory for diagnostic testing”. It goes on: “For older age groups, even when cases do present to the GP, the GP may not diagnose pertussis and would rarely send samples for diagnostic testing”.

While the number of cases of whooping cough was much lower last year, it was noted that the number of children who contracted it had doubled in 2011. Of the total of 229 reported cases in 2011, the highest number (122) were again in the age 0-4 years.

International outbreak

Ireland isn’t alone in the whooping cough outbreak – the UK has seen a large outbreak of the disease, and had started recording an increase in cases as far back as the second quarter of 2011, continuing into the start of this year. A bulletin from the Health Protection Agency in the UK in October this year did note that pertussis is a “cyclical disease with increases occurring every 3-4 years”. A total of 7,728 cases had been recorded in England and Wales from January to October this year.

In New Zealand, two sufferers have died since an outbreak which began in 2011 – the most recent victim was a six-week-old baby in Christchurch who died this week after contracting the illness from her mother. Australia and the US have also been hit by a pertussis epidemic, with Associated Press reporting on Thursday that health officials in Vermont were due to meet to discuss the outbreak there, which has seen the number of cases recorded this year increase to ten times the total of cases in 2011.

Control measures

• The National Immunisation Advisory Committee of the College of Physicians in Ireland (NIAC) recommended earlier this month that women who are between 28 and 32 weeks along in a pregnancy come forward for a booster vaccine containing pertussis. They warned that while the vaccine was also available to women who were in a later stage of their pregnancy, it might not be as effective in protecting their baby. They had this advice:

Women who do not get the vaccine during pregnancy should get the vaccine as soon as possible after birth. Additionally, for premature babies born before 32 weeks of age whose mothers may not have been vaccinated, vaccination of close household contacts is recommended to prevent transmission to the babies who are most vulnerable (this is called cocooning).

• The HSE is also recommending that all health workers who are in contact with infants, pregnant women and those with poor immune systems should also get the booster vaccination.
• Children generally receive the pertussis vaccination as part of the 6-in-1 vaccine administered before they are six months old. They are given a booster at the age of between four and five and again in their early teens. The school immunisation programme is currently underway (but will still be ongoing next year) for first-year students.
• A document released by the HPSC in August of this year gives more detailed guidelines for the management of suspected cases, particularly for those working in a healthcare environment.

History of whooping cough in Ireland

Records kept of pertussis infections – and deaths from the disease – between 1948 and 2011 show that there was a peak of fatal cases in 1948, when almost 5,000 people died that year from pertussis.

A vaccine was introduced in the early 1950s and deaths fell dramatically so that by 1956, the number of cases was falling under 1,000. The HPSC says that there was a resurgence in the number of contractions of the disease in the mid-1970s “following adverse media reports or alleged severe side effects of the pertussis vaccine”, which put people off having the vaccine.

(via HPSC)

The composition of the vaccine has changed since the introductory type in the 1950s, and it is now part of the 6-in-1 vaccine which was introduced in 2008.