Reply To: SARSCoV2 “outbreak” on isle of Barra in Scotland


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#65205
SA

Dave:

“To be honest I read items and then rely on elementary common sense and the “Negative Fact”. The reason herd immunity works is because, if it didn’t, humanity would never have survived since the beginning of time.”

There is of course a grain of truth in that. Diseases emerge all the time and initially they may be lethal and individuals who have some better innate immunity survive and eventually there is adaptation and the disease kills fewer people. But the price in such naturally developing herd immunity is very high. In 1911, measles was first introduced into the Polynesian Island of Rotuma in a non-immune population. As a result the mortality rate from the virus was 12.8%, that is an eighth of the population. This had also previously also happened in Fiji in 1875 with a death rate of 20%. And that is eventually how natural herd immunity works, a high natural death rate until there is immunity in the surviving population or they are vaccinated. The death rate is not the only thing because those who survive also get very ill.
Similarly with Covid-19, because there is no underlying immunity, everyone is susceptible to get the disease. After a year it is estimated that about 5% of the population had been infected with the virus, and we are not sure whether those who had the virus will be sufficiently immune in a few months or a year not to get it again. If we already have 87,000 deaths related to the virus when only 5-10% of the population had the virus then we could be taking about 10-20X 87,000 deaths if we allow natural herd immunity to take place. These are of course rough figures and the numbers may be much less, but still too high. Also for every person who dies maybe 5-10 also have serious disease and require hospital admission which would swamp the health services. In addition all of this itself will paralyze the economy anyway so there will really be nothing to gain. Vaccination would mean achieving immunity for more people quickly and without them being exposed to the virus.