It is not a new word, but lately it has been used extensively. That word is “efficacy.” According to the New Oxford American Dictionary efficacy means to produce a desired result. It can be used in various ways but these days it is most often used with references to the vaccine for COVID-19. It is said to have an approximate 95% efficacy rate.

The root word of efficacy is from the Latin verb “efficere,” meaning “to work out or accomplish.” In medicine it speaks of the ability to intervene to produce a beneficial result. For example, one might say a certain medicine is efficacious in stopping pain or a cough.

While we hear of a 95% efficacy rate for the new vaccines, it means the percentage reduction of disease in a vaccinated group compared to an unvaccinated group. As reported, that high percentage rate is above what scientists expected. Thus, they are thrilled.

Efficacy is not the same as efficiency. Efficacy is performed under controlled circumstances efficiency relates to what occurs under ordinary, uncontrolled conditions.

It can be noted as well that the word efficacy is not limited to science or medicine. It is used in theology as an attribute of scripture. That is, when words of scripture combine with the power of the Holy Spirit it can be efficacious in producing faith and obedience.

The word efficacious is sometimes used with intercessory prayer for another. Thus the question: Does one’s prayer make a difference in the life of the one being prayed for? Several years ago Dr. Mitchell Krucoff of Duke Medical Center in his study of cardiac patients wrote, “We need to know if we can offer better health care if we pay attention to prayer.”

Moreover, in the Catholic church prayers for intercession are part of every Mass. In Judaism prayer for the sick is a regular part of the service. A Muslim may also ask the Imam to say a prayer for one who is sick. Of course, intercession is an essential part of the Protestant tradition. These are the statements; the question is are they efficacious?

This old word dating back to the 13th century has surged into the present, just as the virus has surged. Let us then be thankful the vaccines are surging as well, and so far showing a high efficacy rate. And surely we can give thanks to God and scientists for a vaccine to do battle with the virus that is raging all around the world.

Marion Lark is a retired minister who lives in Henderson.