The coronavirus knows how to separate us, and this week it opened a new battlefield: remnants across meaning of the word “endemic”.
You won’t be surprised to learn that views on this topic are somewhat polarized.
“Covid will soon be endemic, thank God,” she announced in the Wall Street Journal. Monica Gandhi, a physician for infectious diseases and a professor of medicine at the University of California, San Francisco. “Extended immunity, vaccinated and natural, will bring control and a complete return to normal.”
Unfortunately, dr. Gandhi’s article was premature. Posted in September, it came before the delta and omicron waves added another 145,000 deaths in the United States.
Christina Pagel, a professor of operational research at University College London, notes that “the virus is not endemic just because the government minister says it is, and only because people want it to be”.
“Current pattern declining vaccination, new variants of immune avoidance and a minimal public health response seem to condemn us to big jumps once or twice a year, ”she announced last week.
Dr. Helen Salisbury, a senior general practitioner and Oxford academic, added that people may regret talking about Covid becoming endemic as a good thing. “TB and black goats were once endemic in the UK – that doesn’t mean mild, it just means widespread,” she warned.
So what does it actually mean for the disease to become endemic and where are we regarding SARS-CoV-2?
“We need a stricter definition”
Francois Balloux, a professor of computer biology at University College London, was one of the first to speak out about making Covid an endemic disease, saying: “In retrospect, epidemiologists should come up with a stricter definition.”
He says the usual dictionary definition of the word – a disease we regularly find among people in a certain area – is misleading. For epidemiologists, the term is more technical and refers to the reproductive value of a virus that has stabilized at about a unit.
“Basically, it means that immunity in the population keeps things under control,” says Professor Balloux. “An endemic pathogen has stability and predictability, but the complication is that they can still go up and down.”
Influenza has ‘good and bad years’
Influenza is a good example. Its seasonal waves are mostly predictable and are controlled by a mix of natural immunity, vaccines and behavioral changes. There are good years in which he kills very few, and bad years when he can dangerously stretch health services.
Professor Balloux is optimistic that Sar-CoV-2 is going in the right direction. Things are far from perfect, he says, but it would be wrong to say there is no progress. Vaccines in particular have saved a huge number of lives. “With each new wave of virus, there is less room for surprise.”
Adam Kucharski, an associate professor at the London School of Hygiene and Tropical Medicine, believes it may take longer for things to become predictable.
He notes that the development of SARS-CoV-2 may not have stabilized at a gently predictable shift, where each new version comes from a known genus. Omicron didn’t come from a delta line, and a delta didn’t come from alpha, beta, or gamma lines, he says.
“Period of Uncertainty”
“I suspect we still have a period of uncertainty before we can predict the coming years with any confidence,” he told The Telegraph. “The evolution of Covid could stop for a while in a corner in the shape of an omicron, or the omicron could cause a different version, similar to what we would see in seasonal coronaviruses and flu, or we could see another evolutionary surprise.”
For now, cases of omicron in parts of the UK appear to be easing. On Saturday, dr. Susan Hopkins, chief health adviser to the British Health Security Agency, said the number of infections in London and the south-east was unchanged, but was slowly rising in the north.
“All of this means we are seeing a slowdown in the number of hospital admissions, but they are slowing down instead of turning around,” she said.
As there are still more than 2,000 hospitalizations per day and most of the NHS’s regular activities are still delayed, Dr. Hopkins hoped SARS-CoV-2 would become endemic in the UK at a slightly lower level than it is today.
Otherwise, as suggested by the U.S. Centers for Disease Control, we may need another new word. “Hyperendemia refers to a long-term high rate of disease onset,” he notes.
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