Will a vaccine really stop the coronavirus?

 Around the world, throughout this harrowing year, we’ve chanted a mantra: “This will all end once we have the vaccine.”  Well, it might not end right away. The infection rate depends not only on medical technology but also on behavior.  The announcement of an effective vaccine may cause people to believe that the virus is no longer a threat.  They will take off their masks and put on their party hats.  Such risky behavior may raise the infection rate again. For a while, we may be worse off with the vaccine than we were without it.

While we’re at it, let’s note two more ways that behavior affects the covid-19 disease:

Misinformation.  This summer, people interpreted the government’s rollback of lockdowns as meaning that the virus was no longer a problem, so they abandoned masks and social distancing. That might explain the abrupt surge in cases in the United States (and Kazakhstan?). But this problem might be temporary, because people benefit from correcting their mistakes.  And political leaders gain from providing the facts: In the US, the Democratic contender for President, Joseph Biden, is capitalizing on President Donald Trump’s deliberate understatement of the pandemic’s danger early this year.

External cost.  People are not penalized for transmitting the virus anonymously, so they will take too many risks. They will party without worrying that they might pass on the virus to somebody else, because it is not likely that the transmission will ever be traced back to them.  This is a permanent problem, because people don't have an incentive to resolve it. The government could address it by fining the maskless, but that's a political nonstarter.  However, although the problem won’t vanish tomorrow, it may not always be large.  People do consider how their actions affect their family and friends; the external costs are larger for crowded events, like block parties and (darn!) baseball games.

Let’s look on the bright side: Most epidemics do end after a vaccine appears.  But this time, it may take time.  – Leon Taylor, tayloralmaty@gmail.com