Vaccinations are the safest way to acquire herd immunity. This would only work when the majority of the population is vaccinated
All of us are affected by the current COVID-19 pandemic, though the impact of the pandemic and its consequences are felt differently depending on our status as individuals and as members of society.
This pandemic is much more than a health crisis, it's also an unprecedented socio-economic crisis. Apart from falling sick and some unfortunately even succumbing to the disease, many lost their jobs and sources of income, with no way of knowing when normalcy will return.
Till date, there is no definite treatment, and everyone is looking for a 'Magic Bullet' which could end this calamity. One way to defeat this dreaded monster is by developing immunity against it.
When the novel coronavirus i.e. SARS CoV2 started to spread, virtually nobody was immune, hence the virus spread without facing any resistance. Stopping it will require a significant percentage of people to be immune.
This is what we call the Herd Immunity.
Herd immunity is achieved when the majority of the population develops resistance to a highly contagious disease which would limit further spread of the disease. Depending on how contagious the disease is, about 70% to 90% of a population needs immunity to attain herd immunity.
If 80% of a population is immune to a virus, four out of every five people who encounter the infected person, won't get sick and won't further spread the disease. Smallpox, measles, mumps and polio are examples of infectious diseases that were once very common but are now rare because of herd immunity.
Herd Immunity can be achieved in two ways:
1. By developing a natural immunity which may be attained by contracting the disease. Acquiring an infection triggers one's immune system and leads to the production of antibodies.
2. Another way is by vaccinating the population for the disease against which immunity is desired
The idea of developing herd immunity by natural immunity does not make sense in this particular disease. Some of the countries initially adopted this strategy but failed miserably.
We know there is no definite treatment for COVID-19 and if a sizeable population gets infected with it, then the healthcare system might not be able to handle it. Moreover, some patients might suffer from life-threatening complications and may die. For less severe diseases, this approach might be reasonable.
Vaccinations are the safest way to acquire herd immunity. This would only work when the majority of the population is vaccinated. While protection against illness might help those who get vaccinated, it will not prevent transmission of the virus and risk of disease in unvaccinated.
It may well be that vaccinated people will shed fewer viruses. Vaccination may prevent getting infected and falling sick but even if one picks up an infection, it will reduce hospitalisations and deaths by mitigating the disease's severity.
Until a vaccine is widely available, the best course of action is to continue following public health measures i.e. social distancing, wearing mask in public places and practicing good hand-washing hygiene as these also break the virus transmission chain.
(The author is Senior Director and Head, BLK Centre for Chest & Respiratory Diseases, BLK Super Speciality Hospital.)