Pertussis cases spike, then ease

A spike in pertussis in Central Otago may be due to greater awareness or part of a national cycle, Southern District Health Board (SDHB) medical officer of health Dr Naomi Gough says.

Notifications of suspected pertussis, also known as whooping cough, and confirmed cases in Central Otago had both increased since about March, Dr Gough said.

She said in Otago there would normally be three or four notifications of suspected pertussis, which typically included one or two confirmed cases, every week.

In the past three weeks there had been 25 notifications of possible pertussis in Central Otago, of which six were confirmed.

Most of those were from people who had in fact been sick about a month ago, and the spike had now settled, Dr Gough said.

There had also been a spike in Central Otago in March, and in Dunedin and Invercargill earlier in the year. There had been no increase in pertussis this year in Queenstown or Wanaka.

Dr Gough said the reasons for the increase could be twofold.

The first group of reasons was increased awareness of pertussis, the SDHB asking GPs to report all cases of suspected pertussis, and improvement in the testing for pertussis.

Secondly, there seemed to be a four-yearly cycle of pertussis outbreaks nationally. The last significant outbreak in Central Otago was about four years ago, Dr Gough said.

She said it was important to note pertussis was always in the community and its circulation and spikes were normal, although the SDHB was increasingly noticing clusters of pertussis in communities.

But it was also important to remember how highly contagious the bacterial infection was, and the importance of taking adequate measures if someone got sick with it.

People with pertussis were typically contagious for about three weeks and could be prescribed a five-day course of antibiotics. They were advised to stay at home until they had finished taking the antibiotics.

It could be ''annoying'' to have to stay at home, but whooping cough was very dangerous to young unimmunised babies and to older people and those who were undergoing chemotherapy or had otherwise compromised immune systems, Dr Gough said.

She said some people with pertussis had only minor coughing and might not realise they had the disease.

She recommended families check their immunisations were up-to-date, and also consider getting influenza vaccinations.

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