,

Two papers authored by a team at Johns Hopkins Bloomberg School of Public Health could help guide disease outbreak investigations and help develop major health policy decisions during an emerging epidemic.

Both papers were underwritten by the National Center for the Study of Preparedness and Catastrophic Events (PACER) at Johns Hopkins University and come at a time when hospital officials and public health authorities globally are focusing on monitoring the continued spread of the H1N1 flu virus.

In one paper, which is in press at the journal Statistics in Medicine, Hopkins professor Ron Brookmeyer, assistant professor Derek Cummings , research associate Justin Lessler, and Ph.D. candidate Nicholas Reich develop new statistical methods for determining the incubation period of disease.

The Hopkins group’s paper proposes a statistical solution to the issue. An abstract of the paper may be viewed at: www3.interscience.wiley.com/journal/122507367/abstract

The Hopkins team used their new statistical methods to analyze the incubation period of nine infectious respiratory viruses, including SARS, using data from a systematic review of the worldwide literature. Their results were published in the May issue of Lancet Infectious Diseases.

An abstract may be viewed at: www.thelancet.com/journals/laninf/article/PIIS1473-3099(09)70069-6/abstract

The analysis, which is perhaps one of the most comprehensive analyses of incubation periods of respiratory viruses ever performed, provides the best available estimates of the incubation period for these diseases along with ranges to describe variation among cases.

“Reliable quantitative estimates of incubation periods are critically important for developing effective public health policy to contain outbreaks,” said Brookmeyer. They help determine quarantine policy, whether and when to give an “all clear sign,” and are important inputs for epidemic models, he said.