Mass inoculation could turn Covid-19 into simple seasonal inconvenience like the common cold
The coronavirus is expected to remain in circulation for years, according to research, but is likely to become as common as the cold.
With much of the world’s adult population expected to be vaccinated in the next year or two, the virus will linger mostly in children, who typically suffer mild symptoms and often none at all.
Research published in the journal Science on Tuesday suggested that children will become immune to the virus and carry that immunity into adulthood.
The study by Emory University in the US state of Georgia worked on a model that explored possible changes in viral transmission and disease severity of emerging human coronaviruses.
It looked at how viruses changed as they became endemic – or commonly seen in society – and considered three separate measures for immune efficacy that wane at different rates.
Scientists found that similar coronaviruses spur similar immune responses, with SarsCoV-2 – the coronavirus that causes Covid-19 – most similar to the common cold.
“The timing of how long it takes to get to this sort of endemic state depends on how quickly the disease is spreading, and how quickly vaccination is rolled out,” said Emory postdoctoral fellow Dr Jennie Lavine, who led the study.
“So really, the name of the game is getting everyone exposed for the first time to the vaccine as quickly as possible.”
In an endemic state, the virus will remain in circulation but can be controlled. Infections will not increase exponentially and the vast majority of the population who come into contact with it will have some immunity.
An effective inoculation programme could accelerate the endemic state of the coronavirus within 12 months, and researchers predicted that in the years ahead, it will be of concern only to those under five.
Even then, symptoms are likely to be mild, or may not show at all.
Scientists looked at how human beings responded to other coronavirus pathogens such as Sars, Mers and the four common cold viruses to draw their conclusions.
Dr Kavita Krishnan, who is head of laboratory services at Premier Diagnostic Centre in Dubai, and who was not associated with the study, agreed with that theory.
“Sars- Cov- 2 will eventually become endemic and will be no more of a threat than the common cold, similar to other coronaviruses,” she said.
“The process could be shortened by vaccination-induced immunity, which would limit the number of potential hosts to favour less virulent versions of the disease.”
Children are constantly exposed to new pathogens as their bodies develop and build immunity.
It is one theory as to why younger people have been better equipped to fend off the coronavirus.
“Once everyone is exposed to either the virus or vaccine, the adult immune system will be trained to fight the virus and will not be overwhelmed by it, as is the case presently,” Dr Krishnan said.
“Children are more adept than adults in defence against the virus because they are constantly challenged by pathogens new to their bodies.”
Similar research on other coronaviruses, such as the common cold, found a child’s first infection usually occurred before the age of five.
After that, as viruses continue to circulate, children are still infected but do not become ill as their immunity builds.
A similar pattern is expected with the coronavirus in the years ahead.
The adult immune system will be trained to fight the virus and will not be overwhelmed
DR KAVITA KRISHNAN
Head of laboratory services at Premier Diagnostic Centre, Dubai