242.2 Million More Americans Need to Get The Covid-19 Vaccine to Reach Herd Immunity

Written by Jacqueline Slobin, University of Virginia & Spencer Lee, New York University

Quick Digest: 

• Herd immunity occurs when a large percentage of a population is immune to a disease, making its spread within that population highly unlikely.
• We need at least 75% of the United States population to be immune to COVID-19 in order to achieve herd immunity and return to normalcy.
• So far, only 5.3 million Americans have received the Covid-19 vaccine. We will need at least 242.2 million more people to get vaccinated in the coming months for the pandemic to end.

What does herd immunity mean?

The World Health Organization defines herd immunity, also known as population immunity, as the indirect protection from an infectious disease that occurs when a population is immune to the disease itself through vaccination or from past infection. 

In other words, herd immunity is the immunity conferred on members of a population when the majority of the population has been vaccinated or already has some immunity because they have been previously infected with the disease. 

When herd immunity is achieved, disease transmission slows or stops completely because members of the population are unable to infect each other. 

Herd immunity against COVID-19 should be achieved by protecting people through widespread vaccination efforts, NOT exposing them to the pathogen that causes the disease. 

In the United States, two vaccines have received FDA-approval: Pfizer and Moderna. Herd immunity will depend on the number of people able and willing to receive these vaccinations. 

Source: Oxford Vaccine Group