Herd immunity is not all or nothing
President Biden has set an ambitious goal for his covid vaccination program: a 70 percent vaccination rate among all Americans by the Fourth of July. This vision statement is Biden’s latest after his administration has smashed all the prior goals it has set for itself. Talk about underpromising and overdelivering!
The reason Biden has chosen 70 percent as his goal appears to be that this is the arbitrary number epidemiologists have proposed at which we will achieve “herd immunity.” This goal can be achieved through people surviving an infection, thus generating natural immunity to the virus, or through vaccination. Given the mortality rate of covid, achieving this goal through vaccination is far preferable to the alternative.
The theory is that viruses only thrive when they have a universe of succeptible hosts available. In other words, to survive, the virus must have people available who are not immune to the virus infecting each other. There are two routes to achieve that goal. Either stop people from infecting each other by stopping their contact, the approach we took earlier that had a devastating personal, social and economic impact upon Americans; or by making enough people immune that to the virus that it has noone to infect. That’s “herd immunity.” We’re the herd, and the goal is to get enough of us immune to the virus that it has trouble finding new hosts to infect.
The problem with achieving that goal is that there are a certain percentage of Americans who are hesitant to get the vaccine. Research has found that there are four kinds of people who fall within that group. The first, about 8 percent, are waiting to see what happens. They aren’t necessarily opposed to getting the vaccine, but just don’t want to be among the first to do so.
The second group, representing 9 percent, are cost conscious. This is a uniquely American problem, given that in most other developed countries, health care is provided free of charge. And even though the vaccine is supposed to be delivered for free, there are enough stories out there of people being unexpectedly left with huge medical bills that hesitancy for this reason is understandable.