Precautionary actions such as withdrawal of a vaccine from the market, or the use of black box warnings must be proportionate to the degree of scientific certainty, the severity of possible harm, the size and nature of the affected population, and the cost of the actions [29] and [30]. Decisions should also be subject to review in light of new information [20]. Anticipatory decision making

can be fostered by the collection of the highest quality of evidence possible. It should be noted, however, that the premature or complete withdrawal of a vaccine from the market can also cause harm under certain circumstances, and thus a precautionary approach may not always be ethically appropriate. Regulators have the duty to warn people when safety and/or effectiveness find more issues are present with a vaccine. This can include important reminders about waning immunity requiring a booster in order that people remain protected from disease. For vaccines where long-term effectiveness is unknown this is particularly

important, because other measures such as screening may become even more important for people in order to prevent morbidity and mortality. Warnings need to be communicated in a timely and appropriate manner. It must be noted, however, that the social context of immunization programs may be such that premature, or overly alarmist warnings may negatively Libraries impact vaccine acceptance in the population as a whole or in particular sub-populations. Thus, while there is a moral obligation to provide all relevant information about vaccine safety and effectiveness to the Dabrafenib mouse public in the interests of respecting individual autonomy and promoting informed consent, this must be balanced with the need to prevent the spread of disease. Dipeptidyl peptidase Thus, the burden of disease needs to be taken into consideration when warning

the public of possible harm when evidence of harm is uncertain. This consideration speaks to the need to ensure that monitoring activities are proportionate in scope to what is known about the risk-benefit profile of a particular vaccine, as well as to the vulnerability of the population being immunized (see Section 3.5 below). Also, the scale of use (is the vaccine being used in a collective immunization campaign?) should also be taken into consideration when deciding what kind of monitoring activities are necessary to protect the public from harm. Proportionality should inform decisions around whether active or passive monitoring is needed, and whether targeted or universal monitoring is needed. Transparency requires that the rationale for regulatory decisions, as well as the decisions themselves need to be communicated to the public. In addition, risk communication around safety issues with vaccines needs to be made accessible and understandable in a timely manner.