Vaccine Reduces TB Risk

A recently concluded data analysis by a School of Public Health research team could help stem the rising number of tuberculosis cases in the United States.

In yesterday's issue of the Journal of the American Medical Association, the researchers reported that the Bacillus Calmette-Guerin (BCG) vaccine significantly reduces the risk of tuberculosis by an average of 50 percent.

The study, co-authored by Dean of the School of Public Health Harvey V. Fineberg, was prompted by a rise in the incidence of TB nationwide as well as scientific controversy about the effectiveness of the vaccine.

"The results have varied and often people have focused on the fact that they vary verses overall whether the vaccine is effective," said Associate Professor of Epidemiology Dr. Graham A. Colditz, the study's lead author.

The report followed a nine-month investigation and data analysis of 1,264 worldwide studies done on the vaccine during the time period of 1930-1990.

In clinical trials examined by the researchers, vaccine recipients had a 50 percent lower risk of TB than non- recipients. In the same trials, the BCG vaccinehad protected patients from death by TB 71 percentof the time.

The researchers also reported that whenlaboratory cases of TB were considered, thevaccine was even more effective.

Colditz, who is also associate professor ofmedicine at Harvard Medical School, said the aimof the investigation was to evaluate theeffectiveness of the vaccine and to explorevariation among the different studies.

TB rates have risen significantly over the pastdecade. Colditz said that from 1984 through thepresent TB rates have increased at least 20percent nationwide. And in the years from1980-1990, there was a 100 percent increase in NewYork City cases alone.

There have also been reports of recentdrug-resistant tuberculosis strains of the virusin New York City, Miami and Boston.

Research on BCG started in 1908 and vaccinetrials began in the late 1920s. More than 70percent of children worldwide are given the BCGvaccination at birth today.

Although the effectiveness of the vaccine hasbeen debated for the past few decades, the WorldHealth Organization recommended its use and addedit to its extended vaccine program.

"Our results are good evidence that the WorldHealth Organization is well justified in theirpolicy," Colditz said.

The team reported the results to the Center forDisease Control in June.

The CDC now has a working group looking at theapplicability of this vaccine.

"I think we have really put a number on theexpected protection by BCG against tuberculosis,"Colditz said.

"That number can be used by policy groups toreview their policies and potentially reviseUnited States approaches to managing theincreasing incidence of tuberculosis

The researchers also reported that whenlaboratory cases of TB were considered, thevaccine was even more effective.

Colditz, who is also associate professor ofmedicine at Harvard Medical School, said the aimof the investigation was to evaluate theeffectiveness of the vaccine and to explorevariation among the different studies.

TB rates have risen significantly over the pastdecade. Colditz said that from 1984 through thepresent TB rates have increased at least 20percent nationwide. And in the years from1980-1990, there was a 100 percent increase in NewYork City cases alone.

There have also been reports of recentdrug-resistant tuberculosis strains of the virusin New York City, Miami and Boston.

Research on BCG started in 1908 and vaccinetrials began in the late 1920s. More than 70percent of children worldwide are given the BCGvaccination at birth today.

Although the effectiveness of the vaccine hasbeen debated for the past few decades, the WorldHealth Organization recommended its use and addedit to its extended vaccine program.

"Our results are good evidence that the WorldHealth Organization is well justified in theirpolicy," Colditz said.

The team reported the results to the Center forDisease Control in June.

The CDC now has a working group looking at theapplicability of this vaccine.

"I think we have really put a number on theexpected protection by BCG against tuberculosis,"Colditz said.

"That number can be used by policy groups toreview their policies and potentially reviseUnited States approaches to managing theincreasing incidence of tuberculosis