Herd immunity, as its name suggests, happens when many people in a community become resistant to infectious disease thereby stopping the virus from spreading.
To better appreciate how herd immunity works, we must first understand how immunity works. Our body develops protection against viruses in two ways. First, by ‘experience’—when we are infected with a disease, our body learns to fight it. When we recover, our body retains the immunological memory of recognising and fighting the disease the next time the virus attacks.
The second is through vaccinations. Even without contracting the disease, our body creates immune memory through the vaccines.
Similarly, herd immunity can happen in two ways; naturally and otherwise.
Natural immunity within the community is achieved when people develop an immune response against the virus after being exposed to it. In the absence of a vaccine, the only way for a community to be protected from the virus is to have successfully fought it.
Do you remember having chicken pox when you were younger? The red itchy blister rashes that speckle your body, gives you high fever and makes you lose appetite? It may seem terrible for that week or two, but the recovered child gets lifelong immunity against the virus.
Mass vaccination is another way to achieve herd immunity.
Let me paint you an analogy: individuals are like rooms, immunity is the door locks, the community is the building, and viruses are the undesirable tenants. The bigger the population being immunised against the virus, the more locked rooms we have in the building. Since viruses need host cells (or commonly, a human body) to reside, with more locked rooms, there aren’t that many rooms the virus can enter. Social immunity breaks the chains of viral transmission, and in the absence of a place to grow and breed, the virus dies.
Thankfully, we do not need 100% of the population to develop immunity towards the virus. As long as the bulk of the population is protected from the disease, virus circulation is reduced, and the theory of herd immunity remains effective.
One local example is the National Childhood Immunisation Program, is a national vaccination exercise that encourages newborns to be vaccinated from birth to 18 months old.
The Swedish model
Since the early phase of the pandemic, the Swedish government has decided to pursue an anti-lockdown strategy. While social distancing measures are promoted, it is done at the discretion of the residents. Otherwise, life is pretty much the same—the government has permitted bars, restaurants, schools, and gyms to stay open.
How did it work for Sweden?
According to the World Health Organisation, as of 26 May 2020, Sweden has 33,843 confirmed cases, and 4,029 death cases. That’s 395.65 deaths per million.
Sweden is facing an ageing population with 20% of its population above the age of 65. Half of the COVID-19 mortality numbers come from nursing homes. A statement issued by the Swedish embassy in Washington D.C. shared that “the strategy has failed to protect the elderly living in care homes”.
Unfortunately, age and immunity shares an inverse relationship. The aged population is more susceptible to the virus than the younger folks. Therefore, any infection in the elderly has a higher propensity to be much more fatal.
The Sweden approach hinges a lot on personal responsibility and reflects a higher level of perceived trust on the residents.
The U.K. Model
Unlike Sweden, the U.K. has never openly acknowledged that herd immunity was the strategy adopted to manage the pandemic. The pandemic spiralled out of control when the nation witnessed an uncontrollable spike in infected cases and death rates in March 2020.
Following that, the Prime Minister released a statement saying that “many more families will lose their loved ones”, placing the nation in further trepidation.
Subsequently, the government’s delayed actions between 12 and 16 March 2020, despite the escalating death rates, is easily misconstrued as a “herd immunity” response.
According to Sir Lawrence Freedman, a Professor of War Studies at King’s College, the perceived herd immunity response of the U.K. government strategy is “a secondary objective rather than a core strategy”. The herd immunity approach is coupled with active measures to reduce the infection rate—”a suppression strategy rather than a mitigation strategy”.
How did it work for the U.K.?
According to the World Health Organisation, as of 26 May 2020, there are 261,188 confirmed cases, 36,914 death cases. That’s 555.19 deaths per million.
I draw similarities to the chicken pox parties where parents believed that it was more beneficial to “engineer” the child contracting chicken pox to prevent the disease in the child’s later years. However, bear in mind that chicken pox is proven to be largely a manageable disease, and it’s unlikely to be fatal.
Building a herd immunity in Singapore in the context of COVID-19 would be akin to holding a “national COVID-19 party”. Everyone is free to roam, and there would be no social distancing measures in place. It means letting nature do its work, and that everyone in the herd (every Singapore resident) should ideally catch onto the novel virus so that we can build up antibodies for ourselves.
If Singapore were to undertake herd immunity, here are the three main pillars we need to prepare for: social, medical, and economic.
First, we have to gather the vulnerable members of our society and house them in an offshore island off the mainland. With the benefit of hindsight, our vulnerable members should include those above 65 years old, anyone with autoimmune disease or predispose illnesses that deemed them unfit to fight COVID.
On the island, we should ideally have senior citizen friendly infrastructure to support them with their mobility and to ensure safe living. To provide them with COVID-free protection, we need to employ robots and technology to tend to them as all Singaporeans should be treated as COVID carriers and therefore kept away from these vulnerable members.
The isolation period should range anything from 2 months to as long as it takes for Singapore to be declared COVID-free.
Next, let’s talk about our schools. With teachers and students being infected, the schools are no longer closed voluntarily but mandatorily. As no one is well enough to teach, and no one is well enough to learn, home-based learning becomes useless. Our education system has thus, effectively, come to a halt.
Lastly, we need to consider our social fabric—our family. Let’s replay the U.K. headlines on 13 March 2020, “many more families will lose their loved ones”.
Herd immunity, in the absence of vaccination, means mass infection—casualties are inevitable. Are we prepared for this catastrophe—emotionally and logistically?
Everyone has different levels of immunity and thus reacts to viruses differently. According to the statistics from the Ministry of Health Singapore, Singapore hospital beds were slightly below the capacity of 50,000 in 2019. This includes beds in inpatient facilities and long-term care facilities.
With the herd immunity approach, we need to prepare for an influx of inpatients in our hospitals. To cope with this inundation of COVID patients in our wards, we need to ensure that we are equipped with 5.6 million beds for every Singapore resident, which is approximately 120 times more than our current resource.
Besides, let’s not forget our healthcare heroes who are fellow residents; they too are part of our “herd”. For any warded patient, it is likely going to be a situation where “the sick takes care of the sick”.
COVID-19 has left our economy in a financial dry spell. With extended Circuit Breaker measures in place, economic experts are estimating that our economy will shrink between 1 and 4%, which is predicted to be worse than the Asian Financial Crisis in 1997, where our economy contracted by 2.2%. If statistics like this do not speak to you, then a more sobering message is that 1 in 3 employment has been negatively affected due to their labour-intensive nature.
A sick population undergoing herd immunity is not going to be a functioning community. With falling levels of efficiency, it is not an exaggeration to say that some essential functions would either be halted or curtailed. This could potentially mark an economic standstill.
This is Singapore, COVID-19, and herd immunity, all in a picture. The extreme approach requires drastic measures. Having said that, the above proposals are preposterous, and the answer is simple: herd immunity is unworkable.
Scientists estimate that herd immunity can be attained when “at least 60% of the population becomes immune to the virus”.
However, a recent test on 1,118 Stockholm residents by the Swedish Public Health Agency in late April 2020 showed that “only 7.3% of Stockholm’s population has developed antibodies against COVID-19”.
Apart from its futility, herd immunity is an evolutionary-centric theory that disregards humanity. As a national strategy, it is a risky gamble on human lives, a morbid approach to neglect the vulnerable, and nothing but a convenient excuse for tardiness.
Due to the controversy in its approach to human life, it elicits extreme responses. For any national social fabric, it can be very divisive. No decent public healthcare system can stomach the reduction of human lives to brutal arithmetic.
Rather than allowing the virus to pass through the community, vaccines are probably our best bet to build herd immunity. It kills the virus, makes us stronger, lessens the stress on our healthcare system, minimises negative impact on our economy, and reduces the fatalities to the minimum.
As we approach phase 1 of gradual easing measures and lifting of Circuit Breaker, let’s not rejoice prematurely.
The other countries who have lifted lockdowns before us such as South Korea and China have detected new clusters of infection after gradually returning to normality after their lockdown. Though the numbers are not alarming, the reason for the spread remains unexplainable. This further reminds us of the asymptomatic nature of the disease, which keeps us in the dark for much longer.
With easing measures setting in, let’s prepare ourselves for the possibility that there will be a surge in community cases. The gradual easing of social measures does not connote a relaxing of individual hygiene habits and social responsibility. Let’s not forget the hard lessons learnt and the mortality it has caused our nation.
In South Korean President Moon Jae-In’s famous words, “It’s not over until it’s over.”
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