Wednesday, August 02, 2023

Korean CDC Forecasting A Steep Rise In COVID Cases by Mid-August


Our current lull in COVID, while highly welcomed, is unlikely to last as there are two inexorable forces at work.
  • First, our acquired immunity (from vaccines or infection or both) continues to wane over time. 
  • Second, COVID continues to evolve into new, often more antigenically distant variants.
While a booster shot in the fall will hopefully restore some of that lost immunity, much will depend upon the variants that are circulating at the time.  

The very good news, however, is that the vaccine does a good job in reducing the severity of infection (and the risks of hospitalization and/or death), even when it fails to prevent infection. 

Already the CDC (based on limited surveillance) is reporting a modest uptick in COVID cases in the United States for the 2nd week in a row.  Whether this is a blip or a trend will take a few more weeks to determine.


Far more pronounced, the South Korean CDC has reported a steep increase in COVID cases (and to a lesser extent, hospitalizations and deaths) for the past 5 weeks, and today has issued a forecast suggesting a major surge (roughly comparable to last December's wave) by the middle of August. 

Excerpts from the translated statement follow.  I'll have a brief postscript after the break. 


Post Date 2023-08-02 Last modified 2023-08-02 Department in charge Crisis Communication Team, Central Defense Response Headquarters Contact 043-719-9372

* Fix: Blue notation

In preparation for the spread of COVID-19 in the summer,  it is strongly recommended to comply with quarantine rules
  • Practice daily quarantine rules such as wearing a mask, washing hands, observing coughing etiquette, and ventilation/disinfection
  • Prevention of group infection by strictly complying with quarantine rules for vulnerable facilities  
  • High-risk groups, such as those aged 60 or older and those with underlying diseases, need to prescribe and take treatment in the early stage of diagnosis

The Central Accident Handling Headquarters received a report on 'response measures related to the recent increase in COVID-19' from the Central Quarantine Countermeasure Headquarters (Director Ji Young-mi) and discussed it.

 1. Measures to respond to the recent increase in COVID-19

❶ Occurrence Trend

  From the 4th week of June 2023, the number of confirmed cases has been increasing for 5 consecutive weeks, and from the 1st week of July, it has increased by more than 20% compared to the previous week. 

   * Daily average confirmed cases (10,000): (6.4 weeks) 1.7 → (7.1 weeks) 2.2 → (7.2 weeks) 2.7 → (7.3 weeks) 3.6 → (7.4 weeks) 4.5
  As the total number of confirmed cases increases, the number of elderly people aged 60 or older is also increasing. The incidence rate maintained a similar level for 4 consecutive weeks, but increased from the previous week to 29.8% in the 4th week of July. 
   * Percentage of people aged 60 or older (%): (6.4 weeks) 26.8 → (7.1 weeks) 25.6 → (7.2 weeks) 25.2 → (7.3 weeks) 26.7 → (7.4 weeks) 29.8
Severe cases and deaths during hospitalization have fluctuated slightly while maintaining 150 and 100 or less, respectively, since the 1st week of March, 2023, but from the 4th week of July, they are showing an increasing trend accompanied by the occurrence of confirmed cases.
   * Severe case (person): (6.4 weeks) 110 → (7.1 weeks) 117 → (7.2 weeks) 122 → (7.3 weeks) 142 → (7.4 weeks) 170
  ** Death (persons): (6.4 weeks) 58 → (7.1 weeks) 41 → (7.2 weeks) 43 → (7.3 weeks) 51 → (7.4 weeks) 88
 Considering the continuous occurrence of mutations and the duration of immunity through natural infection and vaccination, there is a possibility of small fluctuations once or twice a year. The increase in this summer also shows a predictable and manageable trend, considering the dominance of XBB mutations, which are different from the dominant mutations (BA.1/2, BA.5, BN.1) during the last epidemic period, and the effectiveness of existing vaccines*. 
   * Currently, the main effect of the COVID-19 vaccine is to prevent severe illness and death that lasts for a considerable period of time (8 to 12 months), and the suppression of infection itself through the vaccine is maintained for a short period of time.
In addition, it is estimated that the main reasons for the increase are the increase in the number of people who do not get tested even if they have symptoms due to the lifting of quarantine obligations, lack of ventilation during cooling in summer, and weak adherence to precautionary measures. 

 The number of confirmed cases in the 4th week of July 2023 is about 2/3 of the peak of the epidemic in winter last year (3rd week of December 2022), and the number of deaths is about 1/5 (4th week of December 2022)* am. During the resurgence in the summer of last year, the highest daily number of confirmed cases was 180,729 ('22.8.17).

  * Daily average confirmed cases (persons): ('22.8.3 week) 127,558, ('22.12.3 week) 67,306, ('23.7.4 week) 44,844
** Daily average deaths (persons): ('22.8.4 week) 74, ('22.12.4 week) 59, ('23.7.4 week) 13

❷ Disease risk

 In mid-July 23, the fatality rate was 0.02-0.04%, and the severity rate was 0.09-0.10%, the lowest level. Significantly lower than the fatality rate of 0.10% (BA.1/2 mutation predominance), 0.07% (BA.5 mutation predominance), and 0.10% (BN.1 mutation predominance) during the Omicron pandemic in 2022 and two recurrent epidemics. As a result, the mortality rate of seasonal influenza fell to the level.
  * Decreased to influenza level fatality rate (0.03%~0.07% (WHO), 0.03~0.08% (domestic data analysis))

❸ Mutant virus

 EG.5 (XBB.1.9.2.5), detected for the first time in Korea in April, is a submutation of XBB.1.9.2 and is one of the Omicron mutations renamed in May. The detection rate was more than 5% from the 4th week of June, and the detection rate was 17.8% in the 4th week of July, confirming a continuous increase.  

 Meanwhile, according to the WHO, no increase in the severity of the currently prevalent XBB mutation has been confirmed, and the risk is not high compared to the existing mutation (XBB.1.5 Risk Assessment (6.20) and XBB.1.16 Risk Assessment (6.5.)). 

 However, XBB-type mutations show increased immune evasion ability, so the domestic occurrence situation is closely monitored through monitoring of the XBB sub-lineage.


❹ Short-term forecasting

 In mid-August, the number of confirmed cases is expected to be about 60,000 per day, similar to last year's December (maximum daily occurrence of about 76,000). However, considering the recent steep increase in confirmed cases and the increasing incidence of elderly people aged 60 or older, continuous monitoring of the epidemic situation and risk assessment are necessary.

❺ Assess the situation

Considering the low fatality rate and accumulated medical response capabilities compared to the previous Omicron outbreak, it is necessary to consider the situation of various respiratory infectious diseases, such as the level that can be stably managed, the recent rapid increase in confirmed cases, and the simultaneous epidemic of influenza.

         (Continue . . . )


For the past couple of months - given our summer lull in COVID - I've enjoyed not having to wear a face mask in stores. I still carry one, in case I find myself in in a queue with someone who is coughing, but otherwise I've been fairly lax (although I still go through a lot of hand sanitizer).

But I see the writing on the wall; COVID waves, in some form or another, will likely return every six or eight months for the foreseeable future.
 
Given what we know about the risks of reinfection  (see Nature: Acute and Postacute Sequelae Associated with SARS-CoV-2 Reinfection), and some of the long-term consequences of `long COVID' (see Viruses Review: Cerebrovascular Disease in COVID-19), we are either going to have adjust our daily routines during these waves, or suffer some unpleasant consequences. 
South Korean officials tell us the reasons behind this latest wave  `. . . . are the increase in the number of people who do not get tested even if they have symptoms due to the lifting of quarantine obligations, lack of ventilation during cooling in summer, and weak adherence to precautionary measures. 
A reminder that those who forget their history are often condemned to repeat it.