[Q&A] "COVID-19 Re-positive Cases Have Almost No Transmission Power"

On the 21st, a banner related to the prevention of the spread of the novel coronavirus disease (COVID-19) was installed at Namsan, Seoul. Citizens are resting under the banner. Photo by Mun Ho-nam munonam@

[Asia Economy Reporter Choi Dae-yeol] An investigation into patients who tested positive again after recovering from the novel coronavirus infection (COVID-19) revealed that the virus's transmissibility is at a considerably low level.

Jung Eun-kyung, head of the COVID-19 Central Disaster and Safety Countermeasures Headquarters, stated at a briefing on the 22nd, "Out of 39 virus isolation culture tests conducted on re-positive cases, all six confirmed cases so far have tested negative." Although the genetic amplification test, which detects even traces of the virus, showed positive results, no additional virus was cultured, indicating that the infectivity is almost nonexistent or very low, Jung added.

As cases of re-positivity after release from quarantine have increased, the authorities decided to revise the criteria and guidelines for quarantine release. According to the authorities, as of midnight today, the total number of re-positive cases reached 207, an increase of 15 from the previous day.

Jung Eun-kyung, Head of the Central Disaster and Safety Countermeasures Headquarters for COVID-19 <이미지: Yonhap News>

The following is a Q&A with Head Jung at the briefing.

- What is the proportion of asymptomatic patients, and how do you assess their transmissibility?

▲ In investigating cluster outbreaks with many contacts, the proportion of asymptomatic cases is relatively high. At the Guro Call Center, 8% of confirmed cases were asymptomatic at diagnosis; at Uijeongbu St. Mary's Hospital, 30%; and in the Yecheon-gun cluster outbreak, about 36% showed no symptoms at diagnosis. Some patients develop symptoms during the post-quarantine management period. Further investigation is needed to understand the transmissibility during the asymptomatic phase. We believe the proportion is not large.

- The fatality rate for those in their 70s has exceeded 10%. Are there measures to reduce the fatality rate among the elderly?

▲ Those with underlying conditions or residing in nursing hospitals have weakened immunity, resulting in higher fatality rates. Globally, the fatality rate for those over 80 is over or close to 20%. Prevention is crucial. Social distancing and personal hygiene compliance are more necessary. Families caring for the elderly should especially protect them from exposure to infection. For nursing hospitals and facilities, we are conducting pilot studies on measures such as screening tests to detect cases early.

- In the U.S., low antibody formation rates have led to forecasts of a resurgence. How does our health authority view this?

▲ Regarding antibody formation rates and the possibility of a second large-scale outbreak, many countries have conducted antibody surveys targeting general residents in areas where community infections occurred and have announced results. Most report about 3%, with some up to 14%. Since this is a novel infectious disease, research is ongoing on how much antibody is formed and how long immunity lasts. Most reports indicate very low antibody positivity rates. We must interpret these results cautiously because it is unclear whether samples were appropriately selected, and antibody testing methods are not yet standardized. We also plan to investigate antibody positivity rates in the Daegu and Gyeongbuk regions. We assess that the possibility of a second wave is high.

- Is there a plan to lower the infectious disease crisis alert level?

▲ Although social distancing is being eased, it does not mean a complete return to daily life. We are not considering lowering the crisis level. We continuously review whether adjustment of the crisis level is necessary based on the current status and risk of COVID-19. This is not done by setting objective numbers but through comprehensive evaluation, including risk prediction.

This content was produced with the assistance of AI translation services.