By Jimmy Downs

Thursday Sept 13, 2012 (foodconsumer.org) -- Pertussis not only affects babies and young children, but also adults.  Being obese and prexisting asthma can be risk factors for pertussis in older adults, according  to a study recent published in Clinical Infectious Diseases.

Bette C. Liu of University of New South Wales in Sydney, Australia and colleagues conducted the study and found age, body mass index and pre-existing asthma associated with increased risk for pertussis in older adults.

The study was intended to determine the incidence, morbidity and risk factors for pertussis in adults, particularly those aged 65 or older and it involved 263,094 adults aged over 45 years with a mean age of 62.8 years recruited in the Australian State of New South Wales between 2006 and 2008.  During the follow-up of 217,524 person-years, pertussis notifications, hospitalizations and death records were identified. 

During the follow-up, 205 adults had a pertussis notification and 12 were hospitalized.  Accordingly, incidence rates of pertussis and pertussis-related hospitalization were 94 and 5.5 per 100,000 person-years respectively.

The incidence of a pertussis notification did not vary by age but hospitalization rates increased with age.   Those who were older than 65 years were at higher risk for pertussis related hospitalization risk, compared with those aged 45 to 64 years.

Additionally, after adjustment for age, sex and other factors, participants with obesity or having a high body mass index of 30kg/m2 were 52 percent more likely to be notified of pertussis, compared with those with a BMI of less than 25 kg/m2.  

Those who had pre-existing asthma were 64 percent more likely to suffer pertussis, compared with those without asthma.

The researchers  concluded "Adults older than 65 years are more likely to be hospitalized for pertussis than those aged 45-64 years. Obesity and pre-existing asthma were associated with a higher likelihood of pertussis notification. These findings support adults with these characteristics having a higher priority for pertussis vaccination."

Pertussis, also known as whooping cough, is a contagious respiratory disease that is caused by the bacterium Bordetella pertussis, according to the Centers for Disease Control and Prevention.

Pertussis is featured with uncontrollable, violent coughing and a person with pertussis often needs to take deep breathes which cause a "whooping" sound.  Infants and young children are more vulnerable to the disease, which can be lethal, particularly in babies younger than one year of age.

Although pertussis poses a risk to infants and young children, the disease is relatively rare.  In 2011, according to the CDC, 18,719 cases of pertussis or whooping cough were reported in the U.S.  The death rate was even rarer and the CDC did not report any death from the infection in 2011.

The CDC says the best way to prevent pertussis is vaccination.  But early vaccination with pertussis vaccine may increase death risk in baby girls with low birth weight, according to a study published online on Feb 13, 2012 in Archives of Disease in Childhood.

It is important that strangers not touch babies' faces and hands.  Adult hands are full of all types of bacteria and some times pathogenic bacteria and viruses.  Babies have not yet developed mature immunity and they are more likely than healthy adults to become infected with pathogens.