Vaccinations and the Peltzman Effect – explains why many people have become infected with the Corona virus after being vaccinated.

Last Reviewed Jul 11, 2021

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What is the Peltzman Effect?

Sam Peltzman taught microeconomics at Chicago in 1988. The Peltzman Effect is a theory which states that people are more likely to engage in risky behavior when security measures have been mandated. The Peltzman Effect is named after Sam Peltzman’s postulation about mandating the use of seatbelts in automobiles – it would lead to more accidents. Safety perception increases risk appetite.

I received the following message this morning.
A doctor friend of mine laments: “I treated thousands of patients with Covid 19 for the last several months. But I was not positive. But after taking the vaccination, I became positive with the virus.”

The known facts:

1. The immunity against Covid 19 doesn’t build immediately after the first dose or even immediately after the second. Full fledged immunity takes a few weeks after the second dose.

2. Immunity is not absolute. Even after complete vaccination, a person can get infected. His/her chance of dying or getting a severe infection requiring hospitalisation will be substantially less though.

3. Not all vaccines work to the same extent. The efficacy varies.

4. Not all vaccines are effective against all the variants. A lot of vaccines are less effective against B1.351 (the South African variant), for example.

Now what is this Peltzman effect? And why is it important to know about it?

Peltzman effect means behaviour compensating for the perceived risk. In other terms, people become more careful when they sense greater risk and less careful if they feel more protected.

This means that vaccines are giving a sense of security which leads to a increased risky behaviour.

But the problem is that while vaccines neither give immediate protection or full protection (against infection as against death), the sense of security unfortunately starts much earlier, even before the actual injection. And Peltzman effect comes into play: people wear masks with less caution, do not maintain distance as soon as they reach vaccination centres.

The Peltzman effect in fact started for most people even before they took the vaccine. Many people felt protected just looking at the vaccination numbers. The mask usage, social distancing and hand sanitisation have become progressively less. While this is attributed mainly to pandemic fatigue, the Peltzman effect cannot be ignored.

While this behaviour is dangerous for general public, this can be disastrous for health care workers who directly deal with Covid 19 patients. A lot of them can get infected in the present second wave impairing the health care services.

The Peltzman effect is also evident in the drastic decline in the usage of PPE kits by the healthcare workers.

It is important to vaccinate the majority of the people at risk. But it is also important to be aware of Peltzman effect and be more careful until the effect of vaccination takes us close to herd immunity.

Here is a definite instance where spreading awareness will save lives.