Vaccine efficacy is a term that is used to describe how effective a vaccine is in reducing or managing incidences of disease outbreak in a defined population. This effectiveness is usually derived through the process of contrasting the incidence of the disease in similar populations who may not have received the vaccine as opposed to the rate of outbreak or infection in vaccinated populations. The process of applying vaccine efficacy may be used for any number of purposes, including for the test or trial of a new drug as a means of discovering just how effective the drug is in managing specified health problem. It may also be for the purpose of the collation of data by government or other concerned parties who may wish to use the information for a specified purpose.
Generally, some vaccines are mandatory for certain members of the population; for instance, infants have a regime of vaccinations that are usually applied at predetermined times as their growth progresses. Most of these vaccines have been tested through the vaccine efficacy method whereby the drugs are assessed for their effectiveness in preventing the onset of targeted diseases or infections. Some of these vaccines have been so successful through their usage that they have effectively brought down the outbreak of certain types of diseases around the world. An example of such a disease is polio, which was once dreaded due to the adverse effects that it had on victims. By applying the measurement of the rate of success of polio vaccinations through the assessment of vaccine efficacy, it can be seen that the polio vaccine has indeed been effective in achieving the purpose for which it was developed.
Another reason for the application of vaccine efficacy is for the purpose of clinical trials involving the test of newly developed vaccines. What usually happens in this type of situation is that the pharmaceutical company trying to introduce the drug into the market will conduct series of controlled clinical trials whereby they will administer the drugs to people who may have certain conditions that the drug is targeting with a view to seeing how effective the drug is in managing or reversing the condition. The vaccine efficacy will be determined after an assessment of the ratio of success in reversing, managing or eliminating the condition in people to whom the drugs have been administered in comparison to those who never received the drug.