A security system can include a tag unit adapted to be secured to an infant via band. The first tag unit can include a temperature sensor, and a capacitance sensor. A temperature alarm can be provided in response to a negative slope of a temperature curve associated with temperature data from the temperature sensor. A capacitance alarm can be provided in response to a comparison to capacitance data from the capacitance sensor to a baseline when the tag unit is not secured to the infant. A resistance alarm can be provided in response to resistance data indicating a spike in resistance followed by a relatively flat line response.