Just as the first coronavirus vaccines start to roll out in the US, Dr Anthony Fauci has estimated that “herd immunity” to Covid-19 could be achieved by summer 2021. However, there are a few strings attached: he warned that reaching this target depends on how effectively the vaccines are distributed and whether people are convinced to get the vaccination.
Dr Fauci, the director of the US National Institute of Allergy and Infectious Diseases, has recently said that if widespread vaccination campaigns start in the second quarter of 2021 then the US could reach the “herd immunity” threshold months later by summer 2021. The US has currently only approved the Pfizer/BioNTech Vaccine for emergency use, namely for front-line healthcare workers and residents of long-term nursing care facilities, but they are looking to roll it out this and other vaccines for the general population around early spring.
"The real bottom line is: when do you get the overwhelming majority of the population vaccinated so you can get that umbrella of herd immunity?” Dr Fauci told MSNBC on Monday December 14.
"I believe, if we’re efficient about it and we convince people to get vaccinated, we can accomplish that by the end of the second quarter of 2021. Namely, by the end of the late spring or early summer."
Herd immunity is the idea that a population can be protected from a virus if a certain threshold of vaccination is reached. In other words, when most of a population are immune against a specific disease through vaccination, the remaining minority of the population will also have a reduced risk of catching the infection. This is because immune individuals are unlikely to contribute to the transmission of disease and chains of infection are cut.
In the context of Covid-19, herd immunity has often been used to describe the approach of allowing the controlled spread of the virus through the population without a vaccine. Without a vaccine, it effectively means achieving widespread immunity to the disease by letting the infection rip through the population. This interpretation of the idea has been widely dismissed as unscientific, unethical, and ineffective. Dr Fauci himself has also been highly skeptical of this approach. With a vaccine, however, widespread immunity can be achieved in a controlled and managed way with no cost to human life.
“Let’s say we get 75 percent, 80 percent of the population vaccinated,” Dr Fauci said at the online When Public Health Means Business event last week. “If we do that, if we do it efficiently enough over the second quarter of 2021, by the time we get to the end of the summer, i.e. the third quarter, we may actually have enough herd immunity protecting our society that as we get to the end of 2021, we can approach very much some degree of normality that is close to where we were before.”
So, does that mean everyday life can “go back to normal” by the end of summer 2021? Well, not quite. Dr Fauci believes it will be well into the second half of 2021 before the US can start to think about relaxing social distancing measures, but warned that a vaccine is not a silver bullet against the pandemic. He also argues that many hurdles will remain even when an effective vaccination is widely available.
Vaccine skepticism is one of the many hurdles in the fight against Covid-19, but it can be combated with some informed advice and knowledge. Watch this video of a microbiologist busting some of the most common vaccine myths.
This article has been amended to include a video by Yale University about herd immunity and vaccines.
For more information about Covid-19, check out the IFLScience Covid-19 hub where you can follow the current state of the pandemic, the progress of vaccine development, and further insights into the disease.
