Herd Immunity for Covid-19?

Have you noticed only politicians and some lay people talk about #HerdImmunity? Scientists and business people seem to be talking about #testing, cure and vaccines. Amazon is planning its own tests just for their own workforce. Some of my clients are doing the same. Chemicals for covid-19 diagnostic tests are hard to find but businesses may tap into their global connections to acquire them.

So what is herd immunity?

Herd immunity is an epidemiological concept coming from an idea that ultimately if enough people in a population are immune to a disease then it stops spreading. For instance, if 80 people out of 100 can’t get the disease than the 20 people who can get it remain protected because they may be unlikely to actually get exposed.   

Herd immunity can be achieved in a community in one of the two primary ways.

1) Vaccine access and acceptance:

If a significant number of people get access to the vaccine, they accept it and avail of the opportunity and become non carriers of the virus then even if 5% may not have gotten the vaccine, they may not get the disease because there may not be enough people to get it from. But we don’t yet have a vaccine for coronavirus.

2) Virus has a free rein: 

This is how the politicians have been speaking of herd immunity. Herd immunity is also connected to the argument that the best way to end the social distancing is to allow the virus to run free or at least almost free and in the end the population will achieve herd immunity. This sounds like a creative new idea rather than something horrifying that we should try to avoid at all costs. But let us remember that this only happens after VAST numbers in a population, get infected. So that requires us to “sacrifice the vulnerable on the altar of the economy in vast numbers.”

What kind of vast numbers of fatality might we be speaking of? As per some estimates, herd immunity for Covid-19 can occur after at least 60 to 70 percent of the population develops immunity.  That means at least 60 to 70 percent of the people have to first get infected. Moreover, these have to be random infections. That means, several people would die with a highly contagious virus running free in a society, before herd immunity is achieved.  This would overwhelm our healthcare system and several healthcare professionals would die while working in a high virus load environment.

Even with all our social distancing measures in place, we have a high death count that has brought healthcare system on the brink of overwhelm, in many places. In New York, a dense state with high international travel, there was a death count of almost 15,000 in a population of less than 10M. Healthcare professionals from several other geographical regions traveled to New York to lend help. Can you imagine every state taxed that way beyond their maximum capacity to care for the patients? And that is the reason that scientists and business leaders are not advocating herd immunity as an ultimate preventive measure. We can be lay people and choose to remain ignorant and spread the forwards and myths about herd immunity OR we can listen to what science has to say over what the politicians may be advocating.