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Frequently Asked Questions About Herd Immunity

Medically reviewed by Ika Villanueva Caperonce, MD · Infectious Disease · Makati Medical Center

Written by Lorraine Bunag, R.N. · Updated Sep 20, 2021

Frequently Asked Questions About Herd Immunity

With the arrival of more vaccines, health experts hope to reach herd immunity against COVID-19 sooner rather than later. But what exactly is herd immunity, and how can it help beat this pandemic for good? Find out here.

What is herd immunity? 

Herd immunity or community immunity happens when a significant portion of the population (the herd) is immune against the infection.

How can the population become immune to a disease?

Basically, the community becomes immune in two ways: (1) recovering from the disease and (2) getting the vaccine, both of which provide antibodies against the infection.

The antibodies then stop you from getting sick, or they prevent severe symptoms.

herd immunity covid-19

How many people should be immune to reach herd immunity?

The number of immune people varies depending on how contagious the disease is and the total number of the population, but generally, it involves a high percentage of the population, that can range from 50% to 90%.

To put things into perspective, think about measles. One infected person can spread the disease to up to 18 people. Since it’s highly contagious, herd immunity can be achieved only after about 95% of the community becomes immune.

Why is it vital for us to reach herd immunity? 

With herd immunity, the disease no longer has the upper hand.

To illustrate, imagine a community where no one is immune to the disease. This means everyone who comes in contact with an infected person will get sick and spread the infection to others.

There’s no buffer.

Now, what if 70% of the community is already immune to the infection? That means 7 out of 10 people who encounter an infected person will not get sick and perhaps won’t spread the disease to others. Fewer infections also indicate a lower chance of mutation.

Essentially, immune people act as “shields” for those who don’t have the immunity yet.

Herd immunity is especially crucial for people who:

  • Cannot get the vaccine
  • Never had the disease
  • Cannot gain immunity because of a weak immune system 

Mixing COVID Vaccines Might Yield Positive Results, Study Finds

Is herd immunity possible for COVID-19?

COVID-19 is still a new disease, so researchers still need to confirm a few things, like:

  • Reinfection: When a person recovers from COVID-19, for how long is he or she protected from getting it again?
  • Frequency of vaccination: Are COVID-19 vaccines like flu shots, which we need to get annually?

Nevertheless, health experts are hopeful that herd immunity will end the pandemic.  

Why is vaccination crucial for herd immunity? 

Vaccination is crucial for herd immunity because it’s safer and more practical than natural infection..

As of now, we understand that COVID-19 may lead to severe symptoms and death, especially to people who are of advanced age and those with comorbidities, like obese and smokers. In other words, it’s too risky for them to get immunity through getting infected.

Besides, those who test positive with no or mild symptoms still need intervention.  Additionally, they can an pass it on and harm loved ones. Either they isolate themselves at home and miss work or enter a quarantine facility. Both of these interventions require time and resources.

Another advantage of immunity from vaccination is the fact that last longer than natural infection which is usually only 2-3months.

Vaccination takes only a few minutes and reduces the risk of severe infection.

What’s the status of reaching herd immunity in the Philippines?

Experts believe that to achieve herd immunity against COVID-19, at least 70% of the population must be immune.

In the Philippines, officials say vaccinating at least 50 to 70 million people is enough to reach community immunity.

As of Aug 29 DOH vaccine tracker, 13,785,000 of the population have been fully vaccinated. More than 33,100,000 have received their first dose. 

At this rate, experts think we’ll reach herd immunity in 3.5 years (November 2024).

Key Takeaways

Herd immunity occurs when a high percentage of the community is already immune to the disease. The immune population acts as a buffer between the illness and the unprotected people.

Vaccination is a crucial aspect of reaching herd immunity to COVID-19 because it’s safer, especially for people at risk of developing severe symptoms or those that last longer.

Learn more about Coronaviruses here


Hello Health Group does not provide medical advice, diagnosis or treatment.

Medically reviewed by

Ika Villanueva Caperonce, MD

Infectious Disease · Makati Medical Center

Written by Lorraine Bunag, R.N. · Updated Sep 20, 2021

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