How Much Of The Population Will Need To Be Vaccinated For The Pandemic To End?

As vaccines for COVID-19 begin to roll out around the globe, with some countries including England already beginning the process while others like the U.S. are quickly mobilizing to approve the vaccines and begin distribution, the question everyone is asking is: When will this pandemic finally end? 

While it's impossible to predict an exact date, the total percentage of the world's population that receives the vaccine is a good indicator. The goal isn't to vaccinate 100 percent of people, it's to hit the herd immunity threshold, or the point at which there is a collective immunity and the disease is unlikely to spread (via the Cleveland Clinic). Collective immunity — also known as herd immunity — is the goal of most vaccines. As more people are vaccinated, those who cannot be vaccinated, including newborns and people with certain allergies or immune system problems, are also protected because the spread of a virus is stymied by the population that has been vaccinated (via Our World In Data).

So what percentage do we need?

Our World In Data hasn't crunched the vaccine numbers for COVID-19 specifically, but they've done the research on similar cases. COVID-19 is a virus similar to SARS, and the data on the herd immunity threshold for SARS would be between 50 and 80 percent of the population receiving vaccines — and that means both doses of the vaccine, since both Pfizer and Moderna vaccines will require a second dose. This percentage is higher than the rate for the standard flu, which only needs around a 33 to 44 percent vaccination rate to reach herd immunity status. 

Areas where vaccines are more widely administered may see cases drop earlier than places with less access to the vaccine, so the pandemic won't end all at once, but rather, the rate of transmission will drop in areas as vaccines become more widespread. Some countries, states, and provinces are discussing the potential need to provide an immunization "passport" in order to begin traveling, in order to use more restricted services, or visit high-risk populations (via Global News). 

While there is light at the end of the tunnel, it's clear that we still have months ahead of us before enough people are vaccinated to consider the pandemic "over."