Professor Yoo Jin-hong

I had predicted that about 10,000 people would be diagnosed with coronavirus disease 2019 (COVID-19) around March 10, based on a regression calculation estimated from last week's trend provided by the Korean Centers for Disease Control and Prevention.

Since March 5, however, the number of confirmed patients began to slow down slightly, and as of March 8, the slowdown became clearer. If the new trend continues at this pace, I hope that the number of confirmed cases will decline by next week. Will this plague go away as easily as we want it to, however? If a “third tide” comes around, all hope will be gone, and the vicious cycle will begin again.

Yoo Jin-hong, Professor of the Infectious Diseases Department at Bucheon St. Mary's Hospital

At this point, I would like to point out what conditions must be met for the third wave of infection to occur.

1) A brand new mutant virus: No matter how much it rampages through the country, the disease will eventually die out because the herd immunity will be established someday. However, what if the coronavirus that comes back is not the same as the previous one and, therefore, we will not have developed the immunity against it? Nightmares will begin again. It's even worse.

What's disturbing is that there is a report about new mutations actually emerging. I don't know how reliable this report is, but in any case, it is clear that mutants have appeared.

2) Another outbreak from other gatherings than religious or political rallies, i.e., school or long-term care facility: As we have seen in the ongoing crisis, the plague explodes when two conditions are met: a close contact group in an isolated closed space. Religious and political rallies, as well as social gatherings, are now banned, but the possibility of another outbreak is being downplayed now. Also, there remains a trigger, and I think there are two main types.

One is an outbreak from schools, and the other is from nursing homes or long-term care facilities (I will exclude cruise ships because at least they can be quarantined at sea). The former will not need any further explanation and, therefore, the latter is more worrisome. In the former case, healthy young people are the main members. Still, in the latter, people have many handicaps, such as old age and underlying chronic diseases. Even now, though small and intermittent, news of outbreaks at a nursing home or long-term care facility is being heard. What if this explodes on a massive scale?

3) Inflows from a foreign country: As mentioned earlier, mutations have been reported. If a new outbreak due to new mutants begins, therefore, I think it is likely to be in China. There is no objection to the fact that restrictions on immigration from China are now meaningless given the current domestic situation of community infections in Korea, although I do not agree entirely with the opinion. If a new wave by mutants begins in China, however, we will have to discuss the restriction of entry from China seriously. As we have already been greatly affected by this plague, I think we should ban immigration from China to prevent further spread.

In conclusion, what we should do is evident in case the third wave of infection comes. We may not be able to prevent the emergence of new mutations. Still, it is critical to prepare for the possibility of massive outbreaks at schools and nursing homes, and seriously consider an entry ban on travelers from China this time around.

<The writer is a professor of the Infectious Diseases Department at Bucheon St. Mary's Hospital in Gyeonggi Province. This article was originally published in the Journal of Korean Medical Science. >

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