"COVID-19 Infection Possible from a Single Tiny Liquid Droplet... Severe Loss of Smell, According to UK Study"

Results of Deliberate COVID-19 Infection Experiment

[Asia Economy Reporter Na Ye-eun] A study has found that even a single droplet the size of a blood cell containing the coronavirus can cause COVID-19 infection.

On the 31st (local time), US CNN reported that Dr. Christopher Choo's team at Imperial College London (ICL) in the UK produced valuable insights into COVID-19 through a deliberate infection experiment.

The media also noted that concerns about deliberate infection experiments are expected to ease significantly due to this study. Previously, the study was controversial from the start because it involved intentionally injecting viruses or pathogens into humans.

The research team announced the results of a deliberate COVID-19 infection study conducted on healthy volunteers aged 18 to 30 last March in the international medical journal Nature Medicine.

The team selected healthy individuals without any COVID-19 risk factors such as overweight or obesity, kidney or liver dysfunction, heart disease, or lung and blood problems, and conducted the experiment after providing sufficient information about the study.

To minimize risks, the experiment was conducted in stages. The first 10 infected participants were given the antiviral drug Remdesivir to reduce the possibility of severe progression, and monoclonal antibody treatments were prepared in case symptoms worsened.

The researchers used a long, thin tube to inject small liquid droplets containing the COVID-19 virus into the participants' nasal passages and observed infection status and symptoms for two weeks in a negative pressure isolation room 24 hours a day.

As a result, about half of the participants, 18 people, were confirmed to be infected with COVID-19. Two were asymptomatic, and the 16 who showed symptoms all experienced mild symptoms such as nasal congestion, sneezing, and sore throat.

Among the COVID-positive participants, 83% experienced some degree of loss of smell, and nine could not smell anything at all. Most lost sense of smell recovered after six months, while one participant showed slight improvement but did not fully recover.

Dr. Choo stated that none of the infected participants had lung involvement, which he attributed to their young age and the small amount of virus administered.

Furthermore, the study observed that even a small droplet of about 10mg can cause COVID-19 infection, with a short incubation period. Participants began releasing the virus two days after infection and continued for about six and a half days. However, some infected individuals shed the virus for up to 12 days.

Virus was detected in the throat 40 hours after virus administration and in the nasal passages starting 58 hours after administration.

Additionally, a large amount of virus was emitted even before symptoms appeared, and asymptomatic infected individuals also released significant amounts of the virus.

Dr. Choo said, "This experiment was very successful," and added, "The next study will involve deliberate infection experiments to observe how vaccinated individuals respond when infected with the Delta variant."