As a newly identified coronavirus, called Covid-19, continues to spread across the world, and case rates rise higher in India every day, the issue on a lot of minds is how we can flatten the rapid transmission and how the outbreak would subside. In this context, one often hears about ‘herd immunity’, which Sweden had put its weight behind in the early days of the virus spread. Initially, some other countries like the UK had also preferred developing herd immunity to locking down but later changed tack as the number of cases zoomed.
Coronavirus, emerged in China in December 2019, can affect our lower respiratory tract (lungs and windpipe) or upper respiratory tract (throat, sinuses and nose).
So, what is herd immunity?
‘Herd immunity’, ‘community immunity’ or ‘herd protection’ occurs when so many people around us become immune to an infectious disease that the disease stops spreading rapidly. This way, the whole community becomes protected over time — not just those who are immune.
Will herd immunity work in case of Covid-19?
According to Dr Prasun Chatterjee, associate professor, Department of Geriatric Medicine, All India Institute of Medical Sciences (AIIMS), the coronavirus pandemic "cannot be overcome by thinking that tomorrow we will have a herd immunity. Herd immunity has failed in the UK. There is no point in saying that India has developed herd immunity. We have tried to contain the virus through lockdowns."
How is herd immunity achieved?
Vaccines and infection are two paths to herd immunity for Covid-19. As scientists and pharma companies around the world are working furiously to develop an effective vaccine for Covid-19, it would be the best way of achieving herd immunity without resultant complications or causing illness. But, seeking to achieve herd immunity through infection is an unsafe strategy.
According to scientists, the more socially active individuals are more likely to get infected than the less socially active ones — and they are also more likely to infect people if they become infected. Researchers say that herd immunity is lower when immunity is caused by a disease spreading than when immunity comes from vaccination.
Can we stop the disease from spreading?
Dr Jayaprakash Muliyil, former principal of Christian Medical College, Vellore, says: “It (the pandemic) will reach an exponential phase. Even where you slow it down and you don’t have protection within the community, known to be herd immunity; it will come back.”
How to slow the transmission of Covid-19?
We can reduce the chances of getting infected or spreading Covid-19 by taking some simple precautions:
· Avoid mass gatherings and large events
· Clean your hands regularly, for at least 20 seconds, with an alcohol-based hand rub, or wash them with soap and water
· Cover your mouth and nose with your elbow or tissue when you cough or sneeze
· Stay home as much as possible and keep distance between yourself and others
· If you need to leave your house, wear a mask
· Avoid touching eyes, nose and mouth