COVID-19 Becomes Predictable... Positive Signs of Endemic Transition? [Reading Science]

Variant→Spread Repeated Pattern Confirmed Within 6 Months
Major Outbreak Possible If Population Immunity Weakens Like 'Flu'

[Asia Economy Reporter Kim Bong-su] Recently, new subvariants of the COVID-19 Omicron variant have been emerging one after another, causing concern. However, despite the increased transmissibility and immune evasion capabilities, it has also been confirmed that the pattern of 'variant emergence and spread every 6 months' is repeating. It has been discovered that new variants emerge and cause pandemics during periods when the overall population immunity weakens, similar to influenza (flu). Attention is focused on whether this can lead to an 'endemicization' that can be defended against through focused vaccination at specific times and age groups.

According to the international academic journal Nature on the 9th, scientists from South Africa, where the number of infections is rapidly increasing again due to the recent emergence of Omicron subvariants BA.4 and BA.5, and from North America including the United States, have been releasing such research results. In fact, the recently emerged Omicron subvariants BA.4 and BA.5 have faster transmission and stronger ability to evade the human immune system compared to the original Omicron. However, the high level of immunity formed by previous Omicron infections and vaccinations has prevented severe cases, so despite the increase in infections in regions like South Africa, the severity and hospitalization rates are not at a serious level.

Scientists are rather seeing the emergence of these subvariants as a sign that the evolution of the COVID-19 virus may have settled into a predictable pattern where new variants are created after a certain period to ensure survival and spread infections.

In fact, after the large-scale spread of the COVID-19 virus began in early 2020, South Africa saw the first Alpha variant emerge in mid-2020, causing a surge in cases, followed by Beta at the end of 2020, Delta in mid-2021, Omicron (BA.1, BA.2) in November 2021, and Omicron subvariants (BA.4, BA.5) at the end of April 2022. The virus has been producing variants with stronger transmissibility and immune evasion roughly every six months. Tulio de Oliveira, a bioinformatics professor at Stellenbosch University in South Africa, said, "Until last year, variants seemed to appear suddenly," but added, "The emergence of these subvariants is the first sign that the virus is evolving differently (with a pattern)."

South African scientists report that the recent COVID-19 subvariants BA.4 and BA.5 emerged around mid-December last year to early January this year and have since rapidly spread to become dominant. Currently, it is estimated that 60-75% of reported cases in South Africa are infected with these variants.

However, 'fortunately,' these new subvariants are not causing more severe symptoms than previous variants. In South Africa, daily infections have recently exceeded 5,000, a sharp increase from around 1,200 in early April. However, the number of hospitalized patients has remained below 2,000 since early April, with only a slight recent increase. Professor de Oliveira said, "It is still too early to say that the new subvariants are putting pressure on South Africa's healthcare system," adding, "Hospitals are empty, and the population has a high level of immunity."

Experts expect that if the COVID-19 virus continues to evolve by periodically producing variants in this way, it will follow the path of other respiratory viruses like influenza. That is, it will have a cyclical pattern of infection spread whenever the overall population immunity weakens.

Moreover, many more variants of the COVID-19 virus are expected to emerge in the future. This is because each variant of the COVID-19 virus is genetically distant from one another. For example, if humanity develops sufficient immunity against the Omicron lineage variants, descendants of the genetically distinct Delta variant could suddenly appear and become dominant.

Tom Wenseleers, a professor at the Catholic University of Leuven in Belgium, said, "We can expect to see new variants of some kind appear roughly every six months, and it will be interesting to see if this pattern continues," adding, "Based on the patterns observed so far, that seems to be the case. However, since this has been observed over a short period, caution is needed before concluding this as a general rule."