We might be closer to herd immunity on COVID-19 than we think, a new model has found.
In herd immunity, enough people become infected with (and cured from) a virus, building antibodies that mean, at least for a while, they cannot catch the virus again. When enough people are included in that herd, the virus has few places to go and often dies off, or at least is greatly reduced.
Now, a new study from Nottingham and Stockholm Universities suggests that such immunity might be closer than many in the mainstream media say.
“According to their new mathematical model, far less people need to be infected with COVID-19 in order to reach herd immunity levels,” StudyFinds.com reported.
“That model, which was specially designed just for this study, categorizes people into different groups based on age and social activity levels. Once those factors are incorporated into herd immunity projections, the percentage of a population that would have to become immune drops from 60% to 43%,” they said.
“By taking this new mathematical approach to estimating the level for herd immunity to be achieved we found it could potentially be reduced to 43% and that this reduction is mainly due to activity level rather than age structure,” professor Frank Bell in a press release. “The more socially active individuals are then the more likely they are to get infected than less socially active ones, and they are also more likely to infect people if they become infected. Consequently, the herd immunity level is lower when immunity is caused by disease spreading than when immunity comes from vaccination.
“Our findings have potential consequences for the current COVID-19 pandemic and the release of lockdown and suggests that individual variation (e.g. in activity level) is an important feature to include in models that guide policy,” professor Bell concludes.
But the study’s authors say that their “43% number should not be looked at as an exact value, or even the best possible estimate.”
Even if that number is correct, there still might be a ways to go.
“Generally, 60% has been proclaimed as the herd immunity level needed among populations to stop COVID-19. That percentage was agreed upon because it is the usually accepted percentage of a population that must be vaccinated against an infectious disease to stop an outbreak from occurring,” StudyFunds wrote. “So, that 60% figure is based on the assumption that every member of a community is equally likely to be vaccinated and therefore immune. Of course, that’s clearly not what would happen regarding COVID-19 herd immunity, since there’s no vaccine. Instead, herd immunity for the virus would have to happen due to the virus spreading throughout a population.”