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Source: http://www.theaustralian.news.com.au...-23289,00.html
Adults give kids the whoops
Adults with whooping cough pose a threat to children, reports Health editor Adam Cresswell | September 06, 2008
TEN years ago, fewer than 50 per cent of cases of whooping cough -- widely regarded as a childhood disease -- were recorded in adults over the age of 20. Now the proportion is over 80 per cent.
This is not simply because vaccination has made the disease rare in children and babies, although that is certainly true.
The raw number of reported cases in adults, not merely the proportion of the total, rocketed between 2003 and 2006. Sometimes known as the "100-day cough" because symptoms in adults often last for three months, the disease is spread by a bacterium that causes coughing fits so prolonged they often leave patients gasping for breath. The characteristic sound of the air being sucked into a child's lungs gave the disease its familiar name.
But as whooping cough -- known to doctors as pertussis, after the bug responsible -- can prove fatal in young children, the increasing adult rates are proving a real concern.
"Most people think whooping cough affects only children," says Jessica Wilson, a GP in Sydney's eastern suburbs. "Most people in the community have probably been vaccinated as children, but the protection does wane over time, so you do need the adult booster."
A national study of infants hospitalised by pertussis infection in 2001, published in the journal Pediatric Infectious Diseases, found that parents were the presumed source of the infection in over half of cases (2004;23:246-252).
It's true that the latest graphs, which end in 2005, don't tell the whole story. Some of the increase in adults may be due to increased awareness and testing, which has led to the discovery of more of the cases that were always out there. In addition, there may have been some false positive results caused by the nature of the testing methods.
The numbers of adult pertussis cases have come down since the record highs they achieved in 2005. But there's no doubt that adult numbers have risen strongly over the past 10 or more years, even if the scale of the increase is unclear, and experts say the broad picture remains valid that the main presence of the infection has shifted from younger age groups to older ones.
And that means that adults are now the main reservoir of circulating disease -- and consequently pose a threat to babies too young for vaccination.
Makers of adult boosters are unsurprisingly keen to encourage uptake of their products. Drug giant sanofi pasteur, which makes one of the two boosters on the market, this week circulated information about a new campaign to raise awareness of pertussis. It cited research in the journal Expert Review of Vaccines that found 97 per cent of expectant and new mothers were unaware they they can be the source of pertussis infection in their babies (2006;5(2):175-87).
While some drug company marketing practices are greeted sceptically, few public health and infectious disease experts have anything but support for efforts to increase adult booster uptake. A pertussis booster shot has been recommended for new parents by the National Health and Medical Research Council since at least 2003.
But Professor Peter McIntyre, director of the National Centre for Immunisation Research and Surveillance, says unlike for children, the adult booster is not provided free and the $40 cost is off-putting for many adults who rarely see the need.
"We had a pattern in the late 90s that a lot of pertussis was detected in a lot of primary school-aged kids," McIntyre says. "Then a booster was introduced (for that age group), so that went away. The same thing followed for high school kids.
"Now we are left with the problem that there are no funded boosters for those over about 16 or 17. What we have a concern about is that people who were vaccinated a long time ago are susceptible again."
McIntyre says immunity after vaccination probably lasts for 10-15 years before wearing off, while immunity after actual infection lasts longer -- perhaps 20 or even 30 years. He thinks one likely reason for the increase in reported cases is that GPs are more aware that adult infection is a possibility, and more prone to ordering the appropriate test when confronted with a coughing adult patient.
"The ones we would be particularly concerned about are the grandparent age group, because they are often looking after children, and for them it's been the longest since they were vaccinated. If you are over 60 you are probably too old to have been vaccinated anyway."
Babies are routinely immunised free of charge for pertussis, but as the last of three jabs is not due until six months of age -- and as it takes a short time after that for full immunity to develop -- there remains a significant window of vulnerability during which young babies are at risk, says Paul Effler, medical co-ordinator for immunisations at the Communicable Disease Control Directorate for the West Australian health department which is backing the awareness campaign.
Effler says Western Australia has recorded a "dramatic increase" in cases of pertussis in babies under six months, rising from one case in the whole of last year to 14 cases in the eight months so far this year.
Nationwide, there were 4715 reported cases to the end of August this year, compared to 5328 in the whole of 2007. However, Effler says the number of diagnosed infections are just "the tip of the iceberg".
In 2005, the peak year, there were over 11,000 reported cases nationally. As epidemics seem to strike every three to four years, another peak may be approaching.
Wilson says expectant mothers usually respond well to her suggestions that a booster vaccine is a good idea. But she agrees some adults may not even realise that the unpleasant, persistent cough they are experiencing may be something more sinister.
Another supporter of the campaign is Sexual Health and Family Planning Australia.
Adults give kids the whoops
Adults with whooping cough pose a threat to children, reports Health editor Adam Cresswell | September 06, 2008
TEN years ago, fewer than 50 per cent of cases of whooping cough -- widely regarded as a childhood disease -- were recorded in adults over the age of 20. Now the proportion is over 80 per cent.
This is not simply because vaccination has made the disease rare in children and babies, although that is certainly true.
The raw number of reported cases in adults, not merely the proportion of the total, rocketed between 2003 and 2006. Sometimes known as the "100-day cough" because symptoms in adults often last for three months, the disease is spread by a bacterium that causes coughing fits so prolonged they often leave patients gasping for breath. The characteristic sound of the air being sucked into a child's lungs gave the disease its familiar name.
But as whooping cough -- known to doctors as pertussis, after the bug responsible -- can prove fatal in young children, the increasing adult rates are proving a real concern.
"Most people think whooping cough affects only children," says Jessica Wilson, a GP in Sydney's eastern suburbs. "Most people in the community have probably been vaccinated as children, but the protection does wane over time, so you do need the adult booster."
A national study of infants hospitalised by pertussis infection in 2001, published in the journal Pediatric Infectious Diseases, found that parents were the presumed source of the infection in over half of cases (2004;23:246-252).
It's true that the latest graphs, which end in 2005, don't tell the whole story. Some of the increase in adults may be due to increased awareness and testing, which has led to the discovery of more of the cases that were always out there. In addition, there may have been some false positive results caused by the nature of the testing methods.
The numbers of adult pertussis cases have come down since the record highs they achieved in 2005. But there's no doubt that adult numbers have risen strongly over the past 10 or more years, even if the scale of the increase is unclear, and experts say the broad picture remains valid that the main presence of the infection has shifted from younger age groups to older ones.
And that means that adults are now the main reservoir of circulating disease -- and consequently pose a threat to babies too young for vaccination.
Makers of adult boosters are unsurprisingly keen to encourage uptake of their products. Drug giant sanofi pasteur, which makes one of the two boosters on the market, this week circulated information about a new campaign to raise awareness of pertussis. It cited research in the journal Expert Review of Vaccines that found 97 per cent of expectant and new mothers were unaware they they can be the source of pertussis infection in their babies (2006;5(2):175-87).
While some drug company marketing practices are greeted sceptically, few public health and infectious disease experts have anything but support for efforts to increase adult booster uptake. A pertussis booster shot has been recommended for new parents by the National Health and Medical Research Council since at least 2003.
But Professor Peter McIntyre, director of the National Centre for Immunisation Research and Surveillance, says unlike for children, the adult booster is not provided free and the $40 cost is off-putting for many adults who rarely see the need.
"We had a pattern in the late 90s that a lot of pertussis was detected in a lot of primary school-aged kids," McIntyre says. "Then a booster was introduced (for that age group), so that went away. The same thing followed for high school kids.
"Now we are left with the problem that there are no funded boosters for those over about 16 or 17. What we have a concern about is that people who were vaccinated a long time ago are susceptible again."
McIntyre says immunity after vaccination probably lasts for 10-15 years before wearing off, while immunity after actual infection lasts longer -- perhaps 20 or even 30 years. He thinks one likely reason for the increase in reported cases is that GPs are more aware that adult infection is a possibility, and more prone to ordering the appropriate test when confronted with a coughing adult patient.
"The ones we would be particularly concerned about are the grandparent age group, because they are often looking after children, and for them it's been the longest since they were vaccinated. If you are over 60 you are probably too old to have been vaccinated anyway."
Babies are routinely immunised free of charge for pertussis, but as the last of three jabs is not due until six months of age -- and as it takes a short time after that for full immunity to develop -- there remains a significant window of vulnerability during which young babies are at risk, says Paul Effler, medical co-ordinator for immunisations at the Communicable Disease Control Directorate for the West Australian health department which is backing the awareness campaign.
Effler says Western Australia has recorded a "dramatic increase" in cases of pertussis in babies under six months, rising from one case in the whole of last year to 14 cases in the eight months so far this year.
Nationwide, there were 4715 reported cases to the end of August this year, compared to 5328 in the whole of 2007. However, Effler says the number of diagnosed infections are just "the tip of the iceberg".
In 2005, the peak year, there were over 11,000 reported cases nationally. As epidemics seem to strike every three to four years, another peak may be approaching.
Wilson says expectant mothers usually respond well to her suggestions that a booster vaccine is a good idea. But she agrees some adults may not even realise that the unpleasant, persistent cough they are experiencing may be something more sinister.
Another supporter of the campaign is Sexual Health and Family Planning Australia.
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