[Reading Science] Has COVID-19 been forgotten in the 'Talma'... Will another pandemic not come?

Small-scale outbreaks likely to continue instead of seasonal epidemics
Damage remains but steadily decreasing
"Within a few years, flu and net damage expected to be similar"

With the warm weather, more people are now enjoying 'mask-off (Tal Mask, Talma)' moments on the streets. Public performances, events, and gatherings are thriving, and many people are taking off their masks even on the subway. Restaurants are bustling with groups having dinners. It seems the COVID-19 pandemic that troubled humanity for the past three years has been completely forgotten. It is a welcome development that we have survived the harsh era of the infectious disease and can enjoy life again. However, there remains anxiety in the back of our minds. Will another pandemic strike again?

"Welcome to the era of COVID-19 wavelets (small-scale outbreaks)." This is the experts' response to such concerns, as reported by the international academic journal Nature on the 1st (local time).

First, experts believe that COVID-19 will not cause explosive outbreaks that exhaust hospital beds as it did during the major pandemic over the past three years. However, it has not become a seasonal infectious disease like the flu either. Instead, an era has arrived where small-scale outbreaks, less severe than before, occur irregularly due to the emergence of new variants.

Recently, such small-scale outbreaks have been occurring in the United States and other countries. The impact varies by region and country. In some areas, mortality and hospitalization rates are rising, but not in others. What is clear is that the pattern is entirely different from seasonal illnesses caused by coronaviruses such as the flu or common cold. Trevor Bedford, an evolutionary biology researcher at the Fred Hutchinson Cancer Center in the U.S., said, "Last year, we did not ease COVID-19 prevention measures, so I do not know why the spread has suddenly intensified at this point," but he explained, "COVID-19 will become a continuously circulating respiratory disease and will be less seasonal than other respiratory diseases we are familiar with."

Let’s look at the most recent COVID-19 variant, 'XBB.1.16.' Discovered in India last March, this variant is rapidly spreading, replacing other variants. However, Indian research teams confirmed that this mutation causes relatively mild symptoms like the early Omicron variant and has a low fatality rate. This was based on a study of about 300 infected individuals from late December last year to early last month. Tom Wenseller, a professor at the Catholic University of Leuven in Belgium, said, "Some countries are currently experiencing 3 to 4 infection waves annually, depending on the speed of new variant emergence."

The spike protein, where mutations of the COVID-19 virus occur, is evolving twice as fast as the seasonal influenza virus and about ten times faster than the common cold (seasonal coronavirus). Experts analyze that the rapid mutation rate combined with the short effective duration of the human immune system prevents the virus from establishing a seasonal circulation pattern.

Of course, COVID-19 still threatens people with a much higher infection rate than the flu. In fact, a study in the UK revealed that the number of infections last year was equivalent to the entire population. Researcher Bedford pointed out, "Assuming an ongoing annual infection rate of 50% of the total population, this is much higher than the roughly 20% for the flu."

However, there is no doubt that the overall damage caused by COVID-19 infections has significantly decreased compared to the past three years. For example, South African health authorities have established a system to immediately detect and respond to increases in COVID-19 hospitalizations and deaths, but officials say such events are unlikely to occur in the coming months.

Professor Wenseller said, "Even after the Omicron variant surged a year and a half ago, many deaths from COVID-19 still occur, and the costs are more than ten times higher than those of the flu," but added, "Despite large-scale infection waves, fluctuations in hospitalization and death numbers are small. Most people see hope that within a few years, the net harm of COVID-19 will become similar to that of the flu."