By Sandra Basu
WASHINGTON — The military’s restored program to vaccinate troops with the adenovirus vaccine appears to be paying off, a new study suggests.
After a 12-year hiatus, the military began in October 2011 to vaccinate military trainees with adenovirus type 4 and type 7 Vaccine, Live, Oral (adenovirus vaccine) at military recruit training centers.
In a study published in the March issue of the Armed Forces Health Surveillance Center’s Medical Surveillance Monthly Report, researchers used disease surveillance data from the Naval Health Research Center, San Diego, to estimate the impact of the newly reintroduced adenovirus vaccine on both febrile respiratory illnesses (FRI) rates and the number of viruses identified in ill trainees.
Their surveillance found that “an initial 75% reduction in FRI and a substantial reduction in numbers of adenovirus type 4 in respiratory swabs are consistent with findings from a controlled, randomized, blinded trial conducted in volunteers at two basic training facilities, in which there was a 99.3% reduction in FRI due to adenovirus type 4.”
The results were welcome but not surprising, said Clifford E. Snyder Jr., JD, PhD, the Adenovirus Vaccine product manager in the Pharmaceutical Systems Project Management Office of the U.S. Army Medical Materiel Development Activity, Fort Detrick, MD, and an author of the study.
“Since Ad4 is not the only cause of FRI, and some of the causes of individual FRI cases are never assigned to a specific pathogen, I did not know how much of a reduction would be seen; my very informal estimate was in the range of 60% to 90%. So, a reduction of about 75% in the incidence of FRI, in the aggregated incidence data, was not a surprise,” he told U.S. Medicine.
He added that the vaccine has so far been a “success,” and that surveillance will continue.
For the first time in more than a decade, recruits at USS Red Rover take the adenovirus vaccine during their medical in-processing at the Lovell Federal Health Care Center, North Chicago, Ill. Photo by Lt.
Cmdr. Mark Herwitz.
Restored Vaccine Program
Adenoviruses are transmitted through the air by sneezing and coughing as well as by personal contact. With large numbers of young people brought together to live in close quarters, military basic training sites are ripe for the spread of respiratory illnesses caused by adenoviruses. In very serious cases, those illnesses can even lead to death.
The new vaccine replaced an adenovirus vaccine that went out of production in 1996. Wyeth, the pharmaceutical manufacturer, discontinued production of the vaccine in 1996 after failing to come to an agreement with DoD that would have allowed production to continue. Supplies were exhausted in 1999.
DoD leadership was urged by health officials, both internally and externally, to take action to get the adenovirus vaccine restored. An IoM report in 2000 was critical of DoD’s efforts to restore the vaccine and recommended, “a much greater sense of urgency be placed on re-acquiring an effective adenovirus vaccine.”
This past fall, DoD began shipping out the new vaccine for adenovirus type 4 and type 7, to all military and Coast Guard basic trainee sites, with the expectation that it will prevent about 15,000 cases of the febrile acute respiratory disease each year.
Sustaining the Vaccine
Snyder and his colleagues warned in their study that the vaccine should not be discontinued again.
“Experience with the adenovirus vaccine demonstrates that a highly effective vaccine can be lost if it is so good that the need for the vaccine becomes inapparent,” they wrote. “The return of epidemic adenovirus disease in 1999, following decades of successful control, should serve as a reminder that epidemic activity may return if the vaccine is withdrawn in the future. Restoring a vaccine capability can be costly and require many years to complete.”
Snyder said during the interview that he was encouraged by remarks made by Assistant Secretary of Defense for Health Affairs Jonathan Woodson, MD, at a an Adenovirus Vaccine Recognition Ceremony in March, in which Woodson addressed the issue of sustaining the commitment to immunizations.
“In the case of the adenovirus vaccine that was available to us through to the late 1990s, we somehow forgot the history of disease and the overwhelming benefit of prevention,” Woodson said. “And we committed a cardinal mistake of military strategy in general and of medicine as well. We became complacent. We believed that we had defeated a biological foe, that it was too weak to re-emerge, that the threat had faded. The story of the adenovirus vaccine is a cautionary story for leadership, a story that should warn us about overconfidence.”
Snyder also said he hoped that future leaders will maintain that commitment to sustaining the vaccine.
“With the passage of time, people in senior government positions will be replaced when they retire, with a change in presidential administrations or for other reasons,” said Snyder. “Will the replacements be well-informed about the reasons for acquiring the adenovirus vaccine capability? Will the replacements share their commitment to prevention of FRI? Will the replacements support resource allocation decisions that maintain vaccine availability?”
The study also pointed to another adenovirus serotype of concern known as adenovirus type 14. This adenovirus serotype is not contained in the adenovirus vaccine and caused multiple outbreaks during 2007-2009, the study stated.
“Ongoing surveillance will ascertain whether this serotype, or any other, emerges as a substantial cause of FRI,” the authors wrote.