Saturday, January 10, 2015

Whooping cough proteins evolving ‘unusually’ fast

Whooping cough proteins evolving ‘unusually’ fast

Baby having the DTP jab, which protects against whooping cough
Whooping cough may be evolving to outsmart the currently used vaccine, say researchers.
Analysis of strains from 2012 shows the parts of the pertussis bacterium that the vaccine primes the immune system to recognise are changing.
It may have “serious consequences” in future outbreaks, UK researchers state in the Journal of Infectious Diseases.
But experts stressed the vaccine remains highly effective in protecting the most vulnerable young babies.
There has been a global resurgence of whooping cough in recent years.
In 2012, there were almost 10,000 confirmed cases in England and Wales – a dramatic increase from the last “peak” of 900 cases in 2008.
The outbreak led to 14 deaths in babies under three months of age – the group who are most vulnerable to infection.
Rising figures prompted health officials to recommend vaccination of pregnant women so immunity could be passed to their newborns – a strategy that a recent study showed was working well.

Evolving strains

But there has been much debate among experts about whether the introduction of a new vaccine in 2004 has been a factor in rising rates of whooping cough.
One issue is that immunity from the newer acellular vaccine – which contains specific proteins from the surface of the bacteria – does not seem to last as long as the previous whole cell version, leaving teenagers and adults lacking protection.
In the latest study, researchers analysed the genes coding for the proteins on the surface of the pertussis bacterium responsible for the UK outbreak.
They found proteins being targeted by the vaccine were mutating at a faster rate than other surface proteins not included in the vaccine.
Potentially it means the bacteria is changing quickly to get around immune system’s defences put in place with immunisation.
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What is whooping cough?

Bordetella pertussis
It is also known as pertussis and is caused by a species of bacteria, Bordetella pertussis
It mostly affects infants, who are at highest risk of complications and even death
The earliest signs are similar to a common cold, then develop into a cough and can even result in pneumonia
Babies may turn blue while coughing due to a lack of oxygen
The cough tends to come in short bursts followed by desperate gasps for air (the whooping noise)
Adults can be infected – but the infection often goes unrecognised
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But the researchers are still trying to work out what the changes mean in reality – for example do the mutations boost the ability of the bacteria to cause infection.
“We wanted to look at strains from the UK to see if there was anything sudden that had occurred that had led to these really large outbreaks,” said study leader Dr Andrew Preston from the University of Bath.

Vaccine effectiveness

The “million dollar question” he said was what, if anything, could be done to improve the vaccine – which is still the best defence we have – and prevent future outbreaks.
Options to consider include adding more or different proteins to the vaccine, adding novel adjuvants – chemicals which boost the immune response, or even revisiting the old-style whole cell vaccine, he said.
“Pertussis has a cyclical nature and other big question is are we going to see another increase in late 2015,” he added
Prof Adam Finn, a paediatric immunology expert at the University of Bristol said the importance – or not – of the subtle changes found in the study was as yet unclear.
“But the control of pertussis is a significant worry,” he added.
Only 60% of pregnant women have had the pertussis vaccine and we should be doing more to raise awareness of its benefits, he said.
“There is very good new evidence that vaccinating pregnant women protects their babies. And the group we really want to protect is newborn babies,” he said.

Loom bands ‘inhalation danger’ to young children

Boy wearing loom bands
Doctors are warning parents of the need to be vigilant after a spate of children with loom bands stuck up their noses.
Although medics can usually get them out, there is a real risk children could choke on them, the Journal of Laryngology and Otology reports.
The tiny colourful rubber bands, which can be woven to make bracelets, are one of this year’s most popular toys.
Emergency doctors reported four cases at one hospital in a week.

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It’s not necessarily dangerous if they are stuck up the nose, but when objects are small enough they can go backwards and be inhaled or choked on”
Dr Donald MacGregorPaediatrician
The team at the Monklands hospital, in Scotland, urged parents to keep a careful eye on young children playing with loom bands.
They said an inhaled loom band or clip could prove fatal.
Noses or ears
Dr Iain Bohler, a surgical registrar and report author, who has since moved to New Zealand, said while it was common for children to turn up at hospital with small objects in their noses or ears, medics had only started to see this with loom bands fairly recently.
“Often foreign bodies are removed with little more than distress to the child, however, in the worst case scenario, they can lead to blocked airways, cardiorespiratory arrest and death.”
Dr Bohler said that loom bands could be a lot of fun, unleashing children’s creative minds.
“I would however stress with utmost sincerity, the need for parental vigilance in supervising young children playing with loom bands, or any other toy or item with small parts.”
Global craze
Rainbow loom, the plastic device for weaving the small bands, was invented in 2011.
The craze for making them into jewellery and even items of clothing has taken off worldwide.
Duchess of Cambridge wearing loom band on recent trip to New Zealand
Celebrities including the Duchess of Cambridge and David Beckham have been spotted wearing loom band bracelets.
Two of the children reported by Dr Bohler had inserted one of the s-shaped hooks – used to complete loom band bracelets – into their nose. One child ended up swallowing it after initially choking.
The other two young children had managed to get loom bands stuck in their nasal passages.
Local anaesthetic and crocodile forceps were needed, with the children becoming very distressed at attempts to get the objects out.
Dr Bohler said: “Should any parents be remotely concerned their child has swallowed or inhaled any object, they must contact emergency services immediately.”
Dr Donald MacGregor, spokesman for the Royal College of Paediatrics and Child Health, advised parents to be aware that “small objects will always get into places you don’t want them to be with young children.”
He called for families to ensure they knew what to do in the event ofchoking.

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