Published in El Pais, 3 April 2021.
All countries are vaccinating their population as quickly as possible, and several countries are doing very well. But why several countries had to extend or toughen measures against COVID-19? Could it be that the vaccine does not work? Different studies have shown that vaccines protect between 70% and 90% against the disease. So what happened? Several experts think it is due to the Peltzman Effect.
This theory says that people begin to behave less carefully when some security measures appear. A classic example is that of seat belts in cars. People knowing that they have extra protection begin to drive with less care resulting in more accidents. Knowing this, it cannot be concluded that seat belts cause more accidents or are not as safe as previously thought.
The same is happening with the anti-COVID-19 measures and the vaccine. People who have been vaccinated should behave well under the recommendations of few contacts, distancing, etc., but they do not do so because they feel safe and thus infect those who are susceptible. In addition, people who have yet to receive their vaccine, hear that there are more people vaccinated and believe that it is no longer necessary to respect the rules. All of this gives an exaggerated sense of security. Israel, which began in December with vaccination, just recently reached the necessary level of vaccination that protects society. For this, it has had to introduce the same extra measures in the month of February. France has had to enter a new lockdown since yesterday, despite the fact that it has already vaccinated 17 out of 100 people. Israel only now appears to have COVID-19 under control with more than 100 vaccines per 100 people.
So before returning to a completely normal life, without masks, without distancing, with parties, etc. It is important to wait until we reach a sufficient level of immunity.