Whooping cough germ mutating

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Why am I NOT suprised????

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Tuesday May 22 1:12 PM ET

Resistance to Whooping Cough Vaccine Growing

By E. J. Mundell

ORLANDO (Reuters Health) - The bacterium that causes whooping cough

is mutating to develop resistance to the vaccine used to immunize

Dutch schoolchildren against the disease, researchers report.

``It seems like the bacterium is changing part of its coat, thereby

disguising itself'' from the immune system, according to Dr. Audrey

King of the National Institute of Public Health and the Environment

in Bilthoven, the Netherlands. She presented the findings here

Tuesday at the annual meeting of the American Society for

Microbiology.

Until the advent of the pertussis (whooping cough) vaccine in the

early 1950s, the respiratory illness was a major cause of illness and

death, especially among infants and small children. Since the

introduction of the vaccine (usually administered as part of the

diptheria-tetanus-pertussis combo vaccine), rates for whooping cough

have dropped dramatically in the developed world.

However, in recent years whooping cough has been making something of

a comeback in the Netherlands, the United States and elsewhere.

Comparing old and new strains of the Bordetella pertussis bacterium

under the microscope, King and her colleagues found that, over time,

``at least two proteins located on the outside of the bacterium have

been changed.'' Since vaccines work by ``priming'' the human immune

system to recognize (and attack) such proteins, these changes could

explain why the pertussis vaccine now provides Dutch children with

weaker protection against whooping cough than it did in years past.

This theory was supported by further studies in mice. After

administering the vaccine to a group of mice, King's team infected

them with either an older or present-day version of the whooping

cough bacterium. The result? More mice infected with current strains

of pertussis showed signs of illness than those infected with strains

dominant in years past.

In an interview with Reuters Health, King stressed that the whooping

cough vaccine remains ``effective against serious disease,'' and

there is no cause for immediate alarm. And she said it is difficult

to say whether vaccines used in other countries share deficiencies

similar to the form of the vaccine used in the Netherlands.

``However, there is still room for improvement,'' King added, because

whooping cough vaccines currently in use may not protect children

from less serious forms of illness. She recommends that children

receive booster shots of new and improved vaccines--that recognize

the bacteria's altered ``coat''--in those countries where they are

available.