Negative Vaccine Effectiveness Against Omicron: It Can Happen But Not Always
Understanding what’s really happening without cherry-picking studies.
It’s trending in social media and several sites that Covid-19 mRNA vaccines reduce our immunity — negative vaccine effectiveness — against Omicron, the dominant SARS-CoV-2 variant since late 2021, based on studies or data from Canada, Denmark, the U.K., and Iceland. If you haven’t heard of it, maybe you will soon.
To state this article’s conclusion early, yes, negative vaccine effectiveness against Omicron has happened in certain regions only. But association does not mean causation, so we must also consider other factors that could be responsible for the negative vaccine effectiveness. In the end, the vaccine effectiveness against Omicron is waning fast, pressuring us to update our vaccines.
The negative mRNA vaccine effectiveness against Omicron infection
First, 13 scientists from the Canadian Immunization Research Network Provincial Collaborative Network Investigators released their study as a preprint last month. (Although it’s a preprint, it’s unlikely to fail peer review given that the scientists are from a well-established organization.)
