Attack rate

attack rate

1. Attack Rate FPPT.com

2. Attack Rate An attack rate is a variant of an incidence rate, applied to a narrowly defined population observed for a limited time, such as during an epidemic. The attack rate is usually expressed as a percent, so 10n equals 100.

3. For a defined population (the population at risk), during a limited time period

4. Secondary Attack Rate A secondary attack rate is a measure of the frequency of new cases of a disease among the contacts of known cases. The formula is as follows:

5. To calculate the total number of household contacts, we usually subtract the number of primary cases from the total number of people residing in those households.

6. Risk Ratio A risk ratio , or relative risk , compares the risk of some health-related event such as disease or death in two groups. The two groups are typically differentiated by demographic factors such as sex (e.g., males versus females) or by exposure to a suspected risk factor (e.g., consumption of potato salad or not).

7. Often, you will see the group of primary interest labeled the “exposed” group, and the comparison group labeled the “unexposed” group. We place the group that we are primarily interested in the numerator; we place the group we are comparing them with in the denominator

8. Attributable Proportion The attributable proportion, also known as the attributable risk percent, is a measure of the public health impact of a causative factor.

9. In calculating this measure, we assume that the occurrence of disease in a group not exposed to the factor under study represents the baseline or expected risk for that disease; we will attribute any risk above that level in the exposed group to their exposure.

10. The Mortality frequency measures

11. Mortality Rates A mortality rate is "a measure of the frequency of occurrence of death in a defined population during a specified period of time".

12. 1. Crude mortality rate (crude death rate) The crude mortality rate is the mortality rate from all causes of death for a population. For 10n, we usually use 1000 .

13. 2. Cause-specific mortality rate The cause-specific mortality rate is the mortality rate from a specified cause for a population. For 10n, we use 100,000.

14. 3. Proportionate mortality rates

15. 4. Case fatality rate (Death to case ratio)

16. 5. Age-specific mortality rate An age-specific mortality rate is a mortality rate limited to a particular age group.

17. Infant mortality rate : The numerator is the number of deaths among children under 1 year of age reported during a given time period, usually a calendar year

18. The denominator is the number of live births reported during the same time period . The infant mortality rate is usually expressed per 1,000 live births.

19. b. Neonatal mortality rate : The neonatal period is defined as the period from birth up to (but not including) 28 days .

20. Postneonatal mortality rate The postneonatal period is defined as the period from 28 days of age up to (but not including) 1 year of age

21. Maternal mortality rate The maternal mortality rate is really a ratio used to measure mortality associated with pregnancy. The numerator is the number of deaths assigned to causes related to pregnancy during a given time period.

22. 7. Sex-specific mortality rate A sex-specific mortality rate is a mortality rate among either males or females. Both numerator and denominator are limited to the one sex.