Why Herd Immunity is Not A Viable Solution For COVID-19 Currently

The concept of herd immunity has been hanging around since the start of the COVID-19 outbreak and has been put forward as a viable solution or strategy by various politicians in several countries. Some scientists have even backed the strategy, viewing it as a practical course to tackle the global health crisis but many have also rejected the idea on ethical and practical grounds. Many governments have been heavily criticized for putting forward such a strategy as it would lead to the deaths of thousands of people. Recently, the Trump administration approached the idea again, Politico reported: ‘The Trump administration’s health chief met Monday with a trio of scientists who back the controversial theory that the United States can quickly and safely achieve widespread immunity to the coronavirus by allowing it to spread unfettered among healthy people.’

Herd immunity is a state whereby a virus or disease can no longer easily spread due to the fact that the majority (or enough) of a population is immune to the disease. Not everyone needs to be immune to the disease, but enough people so that the disease cannot find a viable host and eventually peters out. Epidemiologists can normally predict how much of a population needs to be immune to the disease before herd immunity becomes effective, and this depends on the reproduction rate of the disease, known as the ‘R number.’ The R number refers to average number of people an infected person passes the infection on to. Measles is an extremely infectious disease, with an R number between 12 and 18, which means that herd immunity will be achieved when around 92-94% of the population is immune, but for other infections this may be less.

For those who have compromised immune systems or are suffering with another pre-existing condition that will make them more susceptible to an infection, this is particularly beneficial as it safeguards them. However, the way to achieve herd immunity is normally through widespread vaccinations. As scientists across the world have not yet developed a successful vaccination, herd immunity could only be achieved currently by letting the virus infect people and relying on individuals to fight off the infection and thus become ‘immune.’ Highly regarded scientific journal, Nature, reports that ‘Estimates of the threshold for SARS-CoV-2 range from 10% to 70% or even more. But models that calculate numbers at the lower end of that range rely on assumptions about how people interact in social networks that might not hold true…’

Many researchers and scientists believe that pursuing herd immunity is a bad idea, some even suggesting that approximately two million US citizens would die. Nature reported: ‘Deaths are only one part of the equation. Individuals who become ill with the disease can experience serious medical and financial consequences, and many people who have recovered from the virus report lingering health effects.’

Commenting on the Trump administration’s suggestions, which including favoring an aggressive re-opening of the economy and side-lining testing and other health measures. Politco wrote: ‘mainstream medical and public health experts say that seeking widespread, or herd, immunity in the manner the scientists prescribe could result in the deaths of hundreds of thousands or even millions more U.S. residents.’

Despite some speaking positively about the strategy, many epidemiologists have argued against such a method on both ethical and practical grounds, saying that alongside the catastrophic loss of human life, it would not necessarily mean that life and the economy can return to normal, nor do we know if herd immunity can actually be achieved without a vaccination.

Some research suggests that the pursuit of Herd immunity may be ineffective, as immunologists still do not know how long immunity against SARS-CoV-2 would last. Some reports have shown that some people may have become re-infected with COVID-19 after recovering from an initial infection. Researchers are able to test whether people have antibodies that defend against SARS-CoV-2, but it is still too early to see how long these would stay in an individual’s system. If people can become re-infected by the virus after a period of time, Herd Immunity can never be achieved and countless deaths would have resulted from the pursuit of such a strategy.

Nature quoted Dr. Kristian Andersen, an immunologist at the Scripps Research Institute in La Jolla, California, who stated: ‘“There’s no magic wand we can use here, we have to face reality — never before have we reached herd immunity via natural infection with a novel virus, and SARS-CoV-2 is unfortunately no different.” Vaccination is the only ethical path to herd immunity, he says. How many people will need to be vaccinated — and how often — will depend on many factors, including how effective the vaccine is and how long its protection lasts.’