William Haseltine writes that we should not waste time trying to build herd immunity against Covid-19, because it's unlikely we will ever be able to achieve it. New research on the development and decline of Covid antibodies and a wealth of epidemiological evidence on coronaviruses as a whole...
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But we waste critical time with this pointless discussion, because the facts are already quite clear: herd immunity will likely never be achieved for Covid-19 or any other coronavirus. We know this thanks to new research on the development and decline of Covid antibodies and from a wealth of epidemiological evidence on coronaviruses as a whole.
While SARS and MERS are the coronaviruses that grab the headlines, there are four other mostly unknown coronaviruses that are much more common: 229E, HKU1, NL63 and OC43. What we know from 60 years of research into these viruses is that they come back year after year and reinfect the same people -- over and over again.
One New York City study, conducted between the fall of 2016 and the spring of 2018, showed that people could test positive multiple times for infection by the same strain of coronavirus, within the same year.
Antibodies to the virus would increase sharply after infection and peak after about two weeks. But then their presence would decline, generally disappearing entirely somewhere between four months and one year. In one case, a person was reinfected with the same strain of coronavirus after just four weeks from first infection.
Earlier studies showed that the very same strain of a coronavirus that causes a cold one year can do so again the following year. Unlike with flu viruses, which mutate frequently and often infect us with new strains each year, the coronavirus need not change to reinfect. Recent data suggests that SARS-CoV-2 follows the same pattern. Following infection and recovery, all antibodies to the virus begin to fade quickly, including those which may be protective.
Over the past weekend, researchers from the United Kingdom published new research which suggests that SARS-CoV-2 does indeed act like its more common cousins. They studied the presence of neutralizing antibodies -- the specific antibodies needed to fight off reinfection -- and found that a transient neutralizing antibody response was "a feature shared by both a SARS-CoV-2 infection that causes low disease severity and the circulating seasonal coronaviruses that are associated with common colds."
