Bioethics Blogs

Vaccination and the omissions bias.

Vaccination has been in the news recently, as an outbreak of measles hits California. The US virtually eliminated measles around the turn of the century, but it has made a comeback. A big factor in that comeback has been ‘conscientious objection’ on the part of parents, who refuse to have their children vaccinated for religious or ‘philosophical’ reasons. Media reports often focus on the ignorance or confusion of these parents. And there’s plenty of both on show. Prominent anti-vaxxers continue to push the long discredited vaccination causes autism line, while the California conscientious objectors seem to have embraced an ill-informed ‘no chemicals’ line. I want to suggest that these views may be motivated, to some extent and in at least some parents, by the omissions bias.

The omissions bias is the tendency to see harms brought about by actions as more significant and more blameworthy than similar harms brought about by inaction. It plays a role in the moral thought of ordinary people: it is the reason why many people think it would be morally monstrous for a doctor to hasten the death of a terminally ill suffering person but permissible and perhaps even obligatory for the same doctor to withdraw treatment so that the person dies more rapidly. Now think about vaccination from the perspective of the omissions bias.

Experts recommend vaccinations because the benefits of vaccinations very significantly outweigh the costs. There are genuine risks associated with vaccinations. Most side effects are mild and transitory; less common ones, like febrile seizures, are not mild but usually do no lasting harm.

The views, opinions and positions expressed by these authors and blogs are theirs and do not necessarily represent that of the Bioethics Research Library and Kennedy Institute of Ethics or Georgetown University.