Dear Researchers,
In this corona pandemic, we are looking into mainly three possible options of combat i) drugs to treat after infection, ii) vaccine and iii) herd immunity. No the first two options seems to be just a inch of distance as some labs, groups of researchers demands its success and availability in near future and simultaneously some groups raises questions about these like success rate and side effects. Finally the third option comes in front and shows some hope in near future as it was early estimated that about 60% of a community needs to get infected but the recent calculations by the mathematicians from the University of Nottingham and University of Stockholm pointed out that it is enough if 43% of a community gets infected1. Again a seroprevalence survey by Indian Council of Medical Research showed that in Kolkata and surrounding area of West Bengal, India showed that over 14% people have developed COVID-19 antibodies2. So are we approaching towards herd immunity?
Hope you will input you view regarding herd immunity.
Thank you.
1. Article A mathematical model reveals the influence of population het...
2. https://www.firstpost.com/health/over-14-kolkata-residents-have-covid-19-antibodies-finds-icmr-survey-city-far-from-developing-herd-immunity-say-doctors-8535621.html
< click to see the whole attachment> There are a lot of reports showing that only a small percentage of population have been infected. To reach 60% herd immunity, a lot of people would die, especially for those old folks. Attached document (published last week) just one of the many cases to show you only a small percent of people get infected by SARS-CoV-2. Population of San Francisco Mission district area were tested in this case. Phonindra Nath Das
In virtually all countries we are far away from herd immunity. This also depends on the duration of immuity, which apparently is rather short.
Herd immunity means at least 70% of the population being affected by the disease and gain immunity. I think we are so far from that
Anmar Aldewachi It was previously supposed 60% and the recent article published by researchers from the University of Nottingham and University of Stockholm claimed it is 43%, and you are talking about 70%. These point is very confusing! Can you please explain the source from where get 70%? Thank you.
In short, the answer is no.
The complexity of a novel disease in such level create barriers to the supposed herd immunity strategy.
The current situation of COVID-19 is not in favor of herd immunity. Initially, Sweden and few other countries thought like that way but they had to change finally. This way of prevention is very risky in the current situation when we can see so many cases of reinfections and it tells us the story of less immunity or short immunity too. And the mutation is another problem which is a continuous process in its life cycle.
Herd immunity to COVID-19: A distant reality
Herd immunity is unlikely, because some of the patients on contracting COVID-19 never develop any antibodies, other develop it for a very short time, and maximum time recorded has been 3 months.
Many patients are getting reinfected after recovering from COVID-19 infection.
It is well reflected by what is happening in Iran, parts of USA and some other countries facing a second surge.
So, at the moment herd immunity to COVID-19 is a distant reality.
Thank you for your valuable input Muhammad Yousuf sir. One thing I would like to know if some patients never develop any antibodies then how do they recover? As far as I know till there is no such drugs available to clear the virus load.
You have pointed out valuables. Thank you Muhammed Ashraful Alam
Probably, herd immunity in COVID-19 would never be a reality. Neutralizing antibodies that develop in some patients do not last long. Now, France, Spain, and Italy have been facing the second wave of COVID-19 (https://www.dailymail.co.uk/news/article-8669447/Europes-second-wave-takes-hold-cases-rise-France-Italy-Spain.html).
Herd immunity depends on the reproduction number, or R0. The R0 indicate the average number of people that a single person with the virus can infect if those people aren’t already immune. That is higher the R0, the more people need to be resistant to reach herd immunity.
Researchers think that the R0 for COVID-19 is between 2 and 3. This means that one person can infect two to three other people. It also means 50% to 67% of the population would need to be resistant before herd immunity kicks in and the infection rates start to go down.
Let us hope that once the COVID-19 vaccination coverage reaches 70% of the susceptible population, the resulting herd immunity would help to mitigate the spread and the lethality of the SARS-CoV-2. However, it may take years before this becomes a reality in poor countries of the world.