poly: Immunization (was: libertarianism)

Carl Feynman writes:
>At 12:24 PM 2/17/98 -0500, Perry E. Metzger wrote:
>>"Vaccination campaigns" lead the government to spend money on what is
>>very obviously a private and not a public good -- if I am vaccinated,
>>I am personally protected, never mind what the public good side
>>effects might be.
>
>Actually, it's a public good. If a large enough fraction of the population
>is vaccinated against a given disease, the disease cannot spread even to
>the unvaccinated individuals. It's called 'herd immunity'. At
>immunization rates close to those needed to produce herd immunity, the
>public good payoff of each additional immunization becomes arbitrarily
>large. Of course, this doesn't explain why the government requires *every
>single* child to be immunized.
>
>There's also a public safety argument: not being immunized presents a
>hazard to those around one. I'm glad the government requires my neighbors
>to be immunized just like it requires them not to fire guns into the air at

These categories of "public" vs. "private" good are subtle.

There is definitely an externality when people infect each other with
contagious diseases. However, if people could cheaply detect when they
had been infected and by whom, and if the guilty party could pay damages,
then tort law could be sufficient to deal with this externality.

If it was feasible to contract with all the people one might be infected by
regarding whether they had been immunized, then this externality should
also be handled by contract. If it hurt them less to get immunized than
it would help the people they might infect, contracts would require
immunization before contact.

So the "public good" justification for immunization has to be based on
an argument of infeasibility of "immunization before contact" contracts.
But the feasibility of this or any contract depends a lot on the existing
legal context, and on the immagination of contract-writers. The sort of
"private law" many of us here are intrigued by might well turn this
"public good" into a "private good".

Robin Hanson
hanson@econ.berkeley.edu http://hanson.berkeley.edu/
RWJF Health Policy Scholar, Sch. of Public Health 510-643-1884
140 Warren Hall, UC Berkeley, CA 94720-7360 FAX: 510-643-8614
Received on Tue Feb 17 19:42:45 1998