“we thought what was missing from that conversation was, what are the rights of vaccinated people to be protected from unvaccinated people?” he said.
the conclusion, he said, is that “public health is something you actually have to do collectively.”
“what we kind of concluded is that the decision to not be vaccinated — you can’t really regard it as a self-regarding risk (because) you’re creating risk for other people around you by interacting with them,” he said.
the researchers used a mathematical model to estimate how many infections would occur in a population, depending on how much mixing occurred between vaccinated and unvaccinated people. it found that when people mixed with people of a similar vaccination status, infection rates among vaccinated people decreased from 15 per cent to 10 per cent, and they increased from 62 per cent to 79 per cent among those who were unvaccinated.
fisman said that in real life, people tend to spend the most time with people who are similar to them. so, he said, even if vaccinated people are most likely to spend time with others who have received shots, they’re disproportionately impacted when they spend time with those who haven’t.
he said the arrival of more contagious covid-19 variants, such as omicron, have impacted both vaccine effectiveness and public faith in vaccination. but he said that even when vaccine efficacy was lowered to 40 per cent in the model and the reproductive rate was increased to account for a more contagious variant the overall conclusions were the same.