Geographic Spread

One of the indicators we look at is the geographic spread of influenza activity. By looking at where sentinel providers are reporting flu-like illnesses and from where specimens are being submitted for testing, we can tell whether influenza is not active, sporadic, local, regional, or widespread. This is not an indicator of disease severity, only of where the disease is located in Maryland.

Influenza-like Illness Intensity

A second indicator we look at is the proportion of visits to sentinel providers for influenza-like illness (ILI). Intensity is measured against a baseline proportion of visits on a scale of minimal, low, moderate, and high.

Predominant Influenza Strain

A third indicator we look at is the predominant strain of influenza circulating in Maryland. This is important because different strains have different implications for the community. For example, a "novel" or "variant" strain will not have a vaccine available against it for a while. There are also some strains of influenza that have developed resistance against antiviral medication. And there are some strains that will not match the strains in the seasonal flu vaccine. Knowing what is circulating is important in planning and responding to influenza outbreaks. Refer to the weekly report for a full breakdown of the PCR test results reported.