The strategy of allowing mass infections of Covid-19 to attempt to develop herd immunity may be a catastrophic failure because the human immune response to Covid-19 may be similar to the response to a cold. Some protection may be developed through a variety of mechanisms of the immune system, but antibody based immunity may decline within months, like it does for the common cold. www.theguardian.com/…
The study cited by the Guardian is in the pre-publication review process, so it is not yet authoritative, but the data fit what is known about Corona viruses in general so the preliminary data make sense. From a public policy perspective these preliminary results support the public health approaches taken by New Zealand and Germany. The approach taken by the Trump administration and the Republican governors of Florida, Texas and Arizona may lead to mass death without ever achieving the benefits of herd immunity.
In the first longitudinal study of its kind, scientists analysed the immune response of more than 90 patients and healthcare workers at Guy’s and St Thomas’ NHS foundation trust and found levels of antibodies that can destroy the virus peaked about three weeks after the onset of symptoms then swiftly declined.
Blood tests revealed that while 60% of people marshalled a “potent” antibody response at the height of their battle with the virus, only 17% retained the same potency three months later. Antibody levels fell as much as 23-fold over the period. In some cases, they became undetectable.
Although there are not large numbers of patients involved in this study, this type of study does not require the large number of patients that public health studies typically require because it is following antibody levels in the same patients over time. It is not a statistics based study that has human issues that require it to be double blind. Antibody levels are objective data.
There are four other types of coronavirus in widespread circulation, which cause the common cold. “One thing we know about these coronaviruses is that people can get reinfected fairly often,” said Prof Stuart Neil, a co-author on the study. “What that must mean is that the protective immunity people generate doesn’t last very long. It looks like Sars-Cov-2, the virus that causes Covid-19, might be falling into that pattern as well.”
Prof Jonathan Heeney, a virologist at the University of Cambridge, said the study confirmed a growing body of evidence that immunity to Covid-19 is short-lived. “Most importantly, it puts another nail in the coffin of the dangerous concept of herd immunity,” he said.
The bottom line is that Americans are dying for Trump’s delusion that we will develop herd immunity and the virus will go away and the economy will magically rebound. I don’t want to die for a delusion. Please wear a mask and keep your social distancing.