Microbial Immunity

There are at least as many microbes in the human body as there are cells. These naturalized commensal citizens guide development, provide nutrition, and help fight infection. Indeed, by way of resident bacteria, diet may be a significant determinant of susceptibility and virulence of the virus which causes covid-19.

During pregnancy, a mother transfers much of her microbiome to her growing fetus. A neonate attracts a further entourage looking for a secure, warm home.

During infancy, microbiota introduce themselves to their host cells and are registered as residents. Many of these microbes are instrumental in producing the antibodies that immune system B cells use to tag and thereby identify invaders. “The composition, timing and sequence of exposure to commensal microbiota happening predominantly during the first waves of colonisations during early life have an outcome on the resulting B cell receptor repertoire and subsequent immunity to pathogens,” explains microbiologist Hai Li.

Early development is just the introduction of commensal living with microbiota. The natural food we eat has a bevy of bacteria, many of which would happily trade being on a piece of fruit for living inside a digestive tract and having regular food service.

The populations of microbes within us are routinely altered by the foods we eat. A healthy diet begets a hearty microbiome and vice versa. Processed and fast food can devastate a well-intentioned community of gut bacteria, inviting instead more exploitative microbial residents who are less interested in protecting their homeland.

The immune system weakens as a result, making a body more susceptible to infection. “B cell repertoires are largely unique to each individual,” notes microbiome maven and immunologist Stephanie Ganal-Vonarburg.

In sum, the robustness of our immune system depends greatly upon our microbiome during our early years and, ongoing, by our dietary practices and health regime.

V2, the wily virus that causes covid-19, infects the respiratory and/or digestive tract. V2 presents a Darwinist “survival of the fittest” situation to humans.

It is well known that covid-19 is a trifling cold at worst for healthy people. Contrastingly, the situation can become dire for those with abiding health issues. Among those chronic conditions are being tubby or having a bad diet – the very bodily situation which many people have ignorantly or lazily chosen.

Among other selective criteria, V2 is a reaper of those who have made poor lifestyle choices. The sickness and death rates from covid-19 in nations around the world are reflecting this.


Ishi Nobu, “Covid-19 & the microbiome,” (14 July 2020).

Ishi Nobu, “Coronavirus pandemic,” (12 August 2020).

Ishi Nobu, “Microbiome” in The Ecology of Humans (2019).

Hai Li et al, “Mucosal or systemic microbiota exposures shape the B cell repertoire,” Nature (5 August 2020).

Gut microbes shape our antibodies before we are infected by pathogens,” ScienceDaily (5 August 2020).