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Herd Immunity: Is It Possible to Achieve It With COVID-19?



What is Herd Immunity

Since the rate of COVID-19 infections began to increase, you’ve probably heard about herd immunity. Well, there are counties that have implemented lockdowns. Alternatively, there are countries that didn’t put measures into place since they were anticipating herd immunity 

This is because they thought this would help spread the transmission of the virus; it has not been possible. In this article review, we look at the effectiveness of herd immunity. Additionally, we have explained why it has not been achieved with COVID-19. 

What is Herd Immunity?

Herd immunity is also known as herd protection. It’s a state where most of the population is immune to an infectious disease. This provides indirect protection to those who are not immune to the infectious disease.  

What does this mean? Well, for instance, if 80% of the population is immune to the infectious disease, then it means that 4 out of every 5 people who encounter someone with the infection won’t get sick. Besides that, they won’t be able to spread the disease further.  

It has been previously used to control the spread of infectious diseases. For it to be effective. 50%-90% of the population needs to be immune to disease infection. 

How Does It work?

From the definition above, herd immunity can only be attained when a large percentage of the population because immune to an infectious disease. This means that they aren’t able to contract the disease or spread it, and hence the infection will slow down or eventually stop. 

Many viral and bacterial infections are normally contagious. They spread from one person to the person. However, the infection chain can be broken if people can no longer transmit the disease. This helps to protect those who are unvaccinated or those who have a weak immune system, such as: 

  • Babies
  • Older adults
  • Young children
  • Individuals with weakened immune systems
  • Pregnant women
  • People with underlying health complications

Herd Immunity Stats 

The effect of herd immunity percentage effect depends on the infectious disease. In some cases, it can go into effect once 40 percent of the population has developed an immune response. This could be through vaccination. Gut generally, it’s normally achieved when 80-95 percent of the population has developed an immune response.

For instance, for the population to develop herd immunity to measles, 19 out of 20 people must be vaccinated. This means that if a child gets measles, the adults around them won’t get it because they would have been already vaccinated. So, they would have already developed antibodies and hence immune to the disease.

Herd Immunity Stats

Source: Our World in Data 

Since the measles vaccination started, the number of infections has declined and is almost zero; the number of reported measles death annually is almost non-existent. Overall, the goal of herd immunity is to prevent most people from spreading or catching an infectious disease such as measles. 

Does Herd Immunity Work?

It does work for some illnesses. For instance, people in Norway were able to partially develop herd immunity to the swine flu through natural immunity and vaccinations. It should also be noted that the influenza infection in Norway was expected to cause fewer deaths in 2010 and 2011 because the population was immune to it.  

Generally, herd immunity works if it can be achieved. It’s effective in stopping the spread of infectious diseases, including some pandemics. Howeverit’s also unpredictable. So, it can always change without anyone knowing. This means that it’s not 100 percent effective, so it doesn’t always guarantee protection against any disease.

How is Herd Immunity Achieved?

Wellit’s achieved through recovery, infection, or vaccination. The best thing about vaccination is that it creates immunity without people having to contract a disease. 

Herd immunity achieved through infections relies on the number of infected people and those recovering from it. They have to develop antibodies to prevent the possibility of future infections.

How Was Herd Immunity Achieved for Other Infectious Diseases?

There have been several pandemics as well as serious disease infections in the past. Polio, Mumps, Chickenpox, and Measles are some of the infectious diseases that were common in the US. However, they are currently very rare. This is because vaccines have been used over the years to establish herd immunity 

It’s also evident that communities that didn’t have vaccines against these contiguous diseases experienced outbreaks. An example of this is the 2019 measles outbreak at Disneyland. 

Herd Immunity Protection

There are instances where the human body has itself developed immunity before the infections. However, even if the adults in such a case can develop immunity, it’s been established that the infections can still circulate among children. Furthermore, the infections can still affect those with weakened immune systems.  

It’s also worth noting that most viral infections tend to mutate over time. This means that the antibodies developed from the previous infections may only be effective for a short period. SARS-CoV-2 is still new to us. So, we can’t fully depend on the herd immunity theory. 

It should be noted that current research studies indicate that we haven’t yet attained its percentage. To make things worse, new strains of COVID-19 have been recently reported in the UK and South Africa. So, even if patients had developed antibodies for previous infections, they are still at a high risk of being re-infected.

When Doesn’t Herd Immunity Work? 

Herd immunity has its drawbacksOne of them is that people who have the same beliefs regarding vaccinations tend to live in one location. Or they attend the same schools or have the same religious and social organizations. 

In such a case, it would mean that we have many people who are unvaccinated by they are close together. So, once the percentage of the vaccinated individuals in the population drops below the threshold for herd immunity, there will be high exposure to a contiguous disease that would quickly spread throughout the community. 

When Can We Expect Herd Immunity for Covid-19?

Is the coronavirus herd immunity can only happen when the virus can’t spread? This is because it keeps encountering people who are already immune to the virus. But with this pandemic, we have to re-think the herd immunity coved was expected to develop a false promise. 

Scientifically, the reproductive number for COVID-19 is between 2 and 3. This means that herd immunity to COVID-19 can only develop if 70 percent of the population would be infected every nine months. It means that we can’t expect herd immunity for COVID-19This is because it’s impossible to achieve herd immunity to coronavirus through widespread transmission. 

COVID-19 is a highly contagious disease. So, a large percentage will first need to be immune against through before we can achieve herd immunity. The immune can be developed through vaccination or infection.

However, we have already experienced a significant loss of lives. Besides that, the vaccine roll-out is just beginning. This means that a large percentage of the population is still at risk. At the moment, we can only depend on vaccination before immunity can be developed. However, people need to continue to practice social distance and wear masks in public. 

What Should We Expect in the Coming Months?

Even though it was previously thought that coronavirus herd immunity would develop, the surge in Coronavirus cases global indicates otherwise. Scientists have been working diligently over the past eight months to develop an effective vaccine. 

As of December 2020, the Pfizer and Biotech vaccine has been approved for use in the US and UK. Data analysis indicates that it has an efficacy rate of 95% in participants without prior SARS-CoV-2 infection. Moderna COVID-19 vaccine has begun its rollout in the US as well. 

While most of the population remains unaffected by the virus, measures have to be put in place. We have seen numerous cities experiencing numerous and explosive outbreaks. The onset of the winter season means that chances of infection spikes are also high. 

To avoid this, physical distancing and restriction of movement in areas with high infection should be implemented. Until everyone gets a vaccine, we can’t bank our hopes on herd immunization. Life will only go back to normal once we are all safe and vaccinated. 

Final Thought

Herd immunity can be effective in offering indirect protection from infectious diseases. But it can only attain if a sufficient percentage of the population becomes immune to the infection. This means that the disease can no longer be transmitted or contracted.  

However, it’s been difficult to attain herd immunity with COVID-19. This virus is still new to use, and so there’s the need for extensive research. However, with the roll-out of vaccines happening in some countries, we hope that most of the population will soon become immune.

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