Pertussis immunization urged for seniors

To help bolster waning pertussis immunity among Americans, a federal vaccine advisory committee expanded recommendations for the Tdap immunization to include all adults 65 and older.

Vaccinating this age group is expected to reduce incidence of the disease in the U.S. and prevent pertussis-related complications among the elderly, who have an increased risk of developing pneumonia and being hospitalized than other age groups, according to the Advisory Committee on Immunization Practices.

The committee recommends that physicians routinely administer GlaxoSmithKline's Tdap vaccine Boostrix to all adults who have not previously received the immunization or who are unsure whether they received it.

Doctors who only have Sanofi Pasteur's Tdap vaccine Adacel can use it to immunize adults, although it has not been approved by the Food and Drug Administration for the 65-and-older group, ACIP said at a Feb. 22 meeting in Atlanta. The 15-member committee advises the Centers for Disease Control and Prevention on vaccine issues.

Adacel is FDA-approved to prevent tetanus, diphtheria and pertussis in people 11 to 64 years old. Data show, however, that it is safe for use among older adults as well, said Jennifer Liang, DVM, a CDC epidemiologist.

The new guidance updates ACIP's June 2010 recommendation that Tdap be administered to adults 65 and older who anticipate having close contact with a child less than a year old.

"Pertussis is not just a nuisance disease," said Thomas Clark, MD, MPH, a medical epidemiologist at the CDC. "It can cause severe and prolonged complications, including pneumonia that requires hospitalization. Coughing fits can be so bad they break ribs. Hopefully, enough people will get the [Tdap] vaccine that we'll see a real reduction in pertussis incidence."

The CDC said there were 27,550 cases of pertussis reported in the U.S. in 2010, but many more cases, particularly those in older adults, go unreported. One reason for such underreporting is that the condition in older patients can be difficult to distinguish from other coughing illnesses, said Anna Acosta, MD, a CDC epidemiologist.

The CDC estimates that there are 100 cases of pertussis per 100,000 adolescents and adults each year.

Cases of the illness have been rising in the U.S. since the 1980s, particularly among children and infants who are too young to be vaccinated, the CDC said. A 2010 outbreak in California killed 10 infants and hospitalized more than 800 adults and children, making it the state's worst pertussis epidemic in more than 50 years.

Contributing to the nationwide uptick in pertussis is improved reporting and surveillance of the illness as well as waning immunity, Dr. Clark said.

Keeping it simple

An individual's immunity against pertussis is 98% in the first year of completing the five-dose childhood vaccination series, Dr. Clark said. Within five years, immunity declines to about 70%.

The American Geriatrics Society supports ACIP's new recommendation because there probably are significantly more cases of pertussis among adults than recognized, said Kenneth Schmader, MD, the organization's ACIP liaison.

"When pertussis occurs in older adults, it can be pretty serious," said Dr. Schmader, chief of the Division of Geriatrics at Duke University Medical Center and director of the Geriatric Research, Education and Clinical Center at the Durham VA Medical Center in Durham, N.C.

"Since vaccination is a good preventive measure, why not keep it simple and recommend vaccinating all older adults? The simplicity of [the recommendation] is really important for practitioners," he said.

CDC Director Thomas R. Frieden, MD, MPH, has to approve the ACIP recommendation before it becomes official. Infectious diseases experts say his endorsement is likely.