From "Inoculation:"
There are four basic key components to successful inoculation: threat, refutational preemption, delay, and involvement. The first is threat, which provides motivation to protect one's attitudes or beliefs (Pfau, 1997a). Threat is a product of the presence of counterarguments in an inoculation message and/or an explicit forewarning of an impending challenge to an existing belief (see Compton & Ivanov, 2012). The message receiver must interpret that a message is threatening and recognize that there is a reason to fight to maintain and strengthen their opinion. If the receiver of an opposing message does not recognize that a threat is present, they will not feel the need to start defending their position and therefore will not change their attitude or strengthen their opinion (Banas & Rains, 2010, p. 285). Compton and Ivanov (2012) found that participants who had been forewarned of an attack–i.e. threat–but not given the appropriate tools to combat the attack were more resistant than the control group. In this case, the simple act of forewarning of an attack was enough to resist the counterattitudinal persuasion.
The second component, refutational preemption, is the cognitive part of the process. It is the ability to activate one's own argument for future defense and strengthen their existing attitudes through counterarguing (Pfau, 1997). Scholars have also explored whether other resistance processes might be at work, including affect. Refutational preemption provides specific content that receivers can employ to strengthen attitudes against subsequent change. This aids in the inoculation process by giving the message receiver a chance to argue with the opposing message. It shows the message receiver that their attitude is not the only attitude or even the right attitude, creating a threat to their beliefs. This is beneficial because the receiver will get practice in defending their original attitude, therefore strengthening it. This is important in fighting off future threats of opposing messages and helps to ensure that the message will not affect their original stance on the issues (Banas & Rains, 2010, p. 285). Refutational preemption acts as the weak strain of the virus in the metaphor. By injecting the weakened virus–the opposing opinion–into a receiver, this prompts the receiver to strengthen their position, enabling them to fight off the opposing threat. By the time the body processes the virus–the counterattack–the receiver will have learned how to eliminate the threat. In the case of messaging, if the threatening message is weak or unconvincing, a person can reject the message and stick with their original stance on the matter. By being able to reject threatening messages a person builds strength of their belief and every successful threatening message that they can encounter their original opinions only get stronger (Banas & Rains, 2010, p. 285). Recent research has studied the presence and function of word-of-mouth communication, or post-inoculation talk (see Compton & Pfau, 2009), following exposure to inoculation messages (e.g., Ivanov et al., 2015).
Delay is the next element that is necessary in the inoculation process. There has been much debate on whether there is a certain amount of time necessary between inoculation and further attacks on a persons' attitude that will be most effective in strengthening that person's attitude. McGuire (1961) suggested that delay was necessary strengthening a person's attitude and since then many scholars have found evidence to back that idea up. There are also scholars on the other side who suggest that too much of a delay lessens the strengthening effect of inoculation. With this being said, it has been revealed that the effect of inoculation can still be significant weeks or even months after initial introduction or the treatment showing that it does produce somewhat long-lasting effects (Banas & Rains, 2010).
Involvement is the final element of the inoculation process. Pfau, et al. (1997a) defined involvement as "the importance or salience of an attitude object for a receiver" and is “among the most important and widely employed concepts in the scholarly literature on persuasion” (p. 190). Involvement is critical; an individual's involvement with an issue determines how effective the inoculation process will be, if at all. If an individual does not have a vested interest in the subject, they will not perceive a threat and, consequently, will not feel the need to defend and strengthen their original opinion, rendering the inoculation process ineffective.