Can We Achieve COVID-19 Herd Immunity?
With the situation we are facing nowadays, there has been a lot of talk about herd immunity. Experts see it as an opportunity to cope with the pandemic. Is it? Today, Cook It would like to discuss this important issue. In this article, we will touch upon how herd immunity works and whether or not we can achieve it.
Herd immunity happens when a virus fails to spread because it keeps encountering people who are protected against it. Once a sufficient proportion of the population is no longer susceptible, it peters out. Due to this, the virus does not transmit to those who cannot be vaccinated, for example, babies, pregnant women, or people with a weakened immune system.
Achieving Herd Immunity
Vaccination is the most logical and safest way to achieve herd immunity. However, the development and implementation of a vaccine is an incredibly long and resource-intensive process. Thus, so far, we have been unwittingly following the second path: a significant part of the population has been producing antibodies to pathogens. It happens naturally after recovery.
Unfortunately, the second path does not guarantee a successful result. First, the coronavirus takes hundreds of lives every day because not everyone can recover. Second, it has long been proven that the antibodies produced will not protect the person for long. We have already had cases when the same person fell ill with coronavirus multiple times.
For herd immunity to perform its function, it must be at a consistently high level. Therefore, as many people as possible must get vaccinated. There is also a threshold for achieving herd immunity. It depends on the disease and the reproductive number of the virus.
The reproductive number shows how many people can get sick if they come into contact with a sick person. Consequently, the more serious the virus, the higher its reproductive number and the higher the threshold for achieving herd immunity. For example, the reproductive number of measles is approximately 12-18. It is necessary to vaccinate up to 94% of the population to achieve herd immunity.
Herd Immunity Threshold
We do not yet precisely know the herd immunity threshold for COVID-19. Scientists continuously broaden their knowledge on the subject. So far, it seems that the reproductive number of the virus ranges from 2 to 3.2. At this level, it would be sufficient for 50–67 % of the population to develop immunity.
If we focus on actual numbers, then, for example, in the United States, 60 % of the population is 198 million people. Will all these people survive the illness? Hardly. In this case, the mortality rate will be at least 1 million people.
The city of Manaus in Brazil has experienced a severe coronavirus outbreak in May this year. In a short time, about 4 thousand people passed away, most of whom were young people. At the peak, from 44 to 52 % of the population were simultaneously sick. Experts are sure that at that moment, a total of 66 % of people were ill.
After that, new cases of the disease became less frequent. Therefore, the researchers concluded that the city most likely achieved herd immunity. However, the situation is now starting to deteriorate again. Unfortunately, the herd immunity achieved like this is short-lived.
It seems we can only wait for an effective vaccine. Until then, all we can do is be socially responsible. Don’t forget about personal protective equipment and keep your social distance in public places. Take care of your hygiene, and remember that the virus has not gone anywhere. In many countries, the healthcare sector is already on the verge of collapse. Be careful and stay safe!