'Positive After Negative' with Variant Virus Spread... Concerns Over Vaccine and Treatment Effectiveness (Comprehensive)

Virus Detected Late After Incubation Period... Overseas Entrants Must Follow Self-Quarantine Guidelines

[Asia Economy Reporters Seo So-jeong, Kim Ji-hee] The first cluster infection of a variant virus in the local community has occurred, putting quarantine authorities on alert. Starting with a foreigner who entered from the United Arab Emirates (UAE) on December 25 last year, a total of 38 people including family and relatives have been infected with COVID-19 so far, and among them, 4 have been confirmed to have the variant virus. Including these 4, a total of 39 cases of variant viruses have been confirmed domestically to date.

In particular, after the index patient (the first confirmed case) tested positive, the number of related infections increased to 38 within a month, raising the possibility that quarantine guidelines for self-isolation were not properly followed. The index patient tested negative in the first PCR (polymerase chain reaction) test conducted on December 26, the month after entering the country, but tested positive in the test before quarantine release on the 7th of last month. The quarantine authorities estimate that the virus spread to the local community through contact during the self-isolation period. It is possible that the foreigner who tested negative in the first PCR test had contact with family members, etc., while the vigilance for quarantine was lowered.

Professor Kim Ja-young of Catholic Kwandong University College of Medicine said, "There are often cases where the PCR test result changes from negative to positive, and it cannot be ruled out that the specimen collection was not properly done in the first test," adding, "If it is the early stage without symptoms or the incubation period, the virus may not be sufficiently detected." Generally, the incubation period of COVID-19 is known to be about 5 to 7 days, but it can be longer depending on the patient's condition.

Since the variant virus has already spread domestically, there are concerns that further spread is only a matter of time. Professor Kim emphasized, "For overseas entrants, not only the first PCR test but also the PCR test before quarantine release must be negative before strictly following quarantine rules," and added, "Rapid testing and rapid isolation are the top priorities, and measures to strengthen individual responsibility for violating quarantine guidelines, like in Australia and New Zealand, should be considered."

Concerns over Therapeutics and Vaccine Effectiveness... Need to Block Spread of Variant Virus

[Image source=Yonhap News]

There are concerns that the vaccine, which is expected to be introduced domestically this month amid the possibility of local spread of the variant virus, might be rendered ineffective. Although the currently developed COVID-19 vaccines are generally evaluated to be effective against variant strains, definitive analysis on preventive effects has not yet been conducted. Authorities also take a cautious stance, stating that additional analysis and review are needed regarding the preventive effects of existing vaccines against variant viruses.

Research results indicating that variant strains reduce the effectiveness of some vaccines are emerging. Among the five vaccines scheduled for domestic introduction (AstraZeneca, Pfizer, Moderna, Janssen, Novavax), Novavax and Janssen vaccines showed about 50% effectiveness in preventing variant virus infections in clinical trials. The preventive effects of the other three vaccines have not yet been investigated. Meanwhile, vaccine manufacturers such as Pfizer have started improving the performance of existing vaccines to be effective against variants.

Due to the variable of the variant virus, there are considerable concerns that the government's goal of achieving herd immunity by November may face setbacks. Experts advise continuing research on the vaccine and therapeutic effects against the variant virus but emphasize focusing on quarantine measures above all.

Professor Lee Jae-gap of Hallym University Department of Infectious Diseases said, "Currently, the key is to delay the spread of the variant virus as much as possible and to promptly carry out vaccination," adding, "For now, we must block the overseas inflow of variant viruses, detect local community infections, and consider adjusting social distancing levels according to the variants."

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