Recently, data from a clinical trial of inoculating humans with the new coronavirus was published in the journal Nature Medicine.. Yes, don’t question, you didn’t look at it.This isThe first study to actively inoculate the new coronavirus into the human body of young adults, called “SARS-CoV-2 Human Challenge”. It was done by epidemiologist and Chinese-American professor Christopher Chiu and his team from Imperial College London, with support from the pharmaceutical company Open Orphan and the UK Department of Health and Social Care (DHSC).
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themInoculated 36 young and healthy volunteers with 2019-nCoV, evaluated its virus kinetics, safety, and tolerance, and finally successfully constructed an infection model of 2019-nCoV in humans. At the same time, it also provides us with a detailed analysis of the human body’s process of infecting and eliminating the new coronavirus from the perspective of virus detection and infection symptoms, which may be helpful for the research and development of epidemic prevention or new crown vaccines.
In 2022, the epidemic called COVID-19 is still raging around the world. Singularity Cake’s colleagues in Shanghai have all started growing vegetables at home.
In order to deal with the new coronavirus, scientists have come up with various animal models and large-scale cohort studies for in-depth and multi-faceted exploration, and even the general teacher has come out to contribute a love.
However, there is a way that no one has tried yet—Can we take the initiative to control the new crown virus and make a big living person become our pathological model?, just like animal models of human disease constructed in basic experiments. Wouldn’t this allow for a greater understanding of the impact of the new coronavirus on the human body?
This is the “SARS-CoV-2 Human Challenge”. Everyone can see here that this research not only challenges the new coronavirus, but also challenges some ethical issues.
In fact, in the early days of the new crown pneumonia epidemic, some scientists advocated launching such trials against the new crown virus to accelerate the development of vaccines.But opponents said that there was little understanding of the virus at the time, and there was no effective treatment as a back-up. In case of an irreversible situation, there was no turning back.。
In the face of the intermittent and continuous rampant new crown epidemic, with the new crown medicine in hand,Professor Christopher Chiu will lead his team to start this extraordinary research in 2021.
They selected 36 people from tens of thousands of applicants as volunteers for the clinical trial.The average age of these volunteers is 22 years old (18-29), they are healthy, belong to the low-risk group of the new crown, have never been infected with the new crown, and have not received any new crown vaccine。
It is worth noting that in this trial, the researchers used a strain from the early stage of the new crown epidemic (SARS-CoV-2/human/GBR/484861/2020) for research. The strain was extracted from a new crown patient early in the new crown epidemic and has not yet shown any significant mutation.
When inoculated with the virus, the researchersInoculated in small doses via nasal drops（10 TCID50). After being vaccinated, the volunteers were taken to a negative pressure isolation ward at a London hospital and placed under 24-hour medical monitoring. Each person is isolated for at least 14 days, and can only leave after meeting the discharge criteria. Over the next year, the researchers followed them up to assess the sequelae of Covid-19 infection.
At the time of statistics, 2 volunteers were excluded due to seroconversion,Finally, a total of 34 people were included for analysis.。
Among them, according to the PCR test results,53% (n=18) “successfully” contracted Covid-19。incubation period(from initial exposure to virus detection or early symptoms)Average time is 42 hours，And up to 12 days after infection, active virus can still be detected from volunteers。
Then let’s talk about something that everyone likes to hear – what’s the difference between picking your throat and poking your nostrils?
The researchers found that,40 hours after infection (≈ 1.67 days), a positive throat swab can be detected;andAfter 58 hours (≈ 2.4 days), a positive nasal swab can be detected。
However, in terms of viral load (VL), the peak VL in the nasal cavity after infection reached 8.87 log10 copies/ml (95%CI 8.41-9.53), while peak VL in throat was 7.65 log10 copies/ml（95%CI 7.39-8.24）。
That is,Positive can be seen earlier in the throat, and more virus in the nostrils。
Moreover, it takes an average of 5 days (148 hours) for the VL in the nasal cavity to reach its peak value, and the symptoms of infection with the new crown also appear around the 5th day.
Among the 18 volunteers infected with the new crown,88.9% had mild to moderate cold-like symptoms such as nasal congestion, rhinitis, sneezing, sore throat, and 39% had fever (>37.8℃). Other symptoms include headache, muscle aches and fatigue.
In addition, anosmia is also common. When the VL in the nasal cavity reaches its peak,83% (n=15) had this symptom, and 50% (n=9) lost their sense of smell completely. On the 28th day after infection, 61% still reported varying degrees of smell disturbance; on the 180th day, 28% had not yet fully recovered their sense of smell.And after that, onlyPersistence of olfactory disturbance in 1 person。
The researchers emphasized that,Although VL kurtosis was temporally associated with symptom onset, it was not associated with symptom severity. In this study, the young volunteers had only mild to moderate symptoms after infection with the new coronavirus, and did not experience any severe symptoms.
Not only that, but the researchers also tested the effect of the LFA rapid antigen test. turn out,Twice a week, LFA rapid test can make a diagnosis before most of the active virus (70%-80%) is producedto avoid further spread of the virus.
Overall, this isThe first study of actively inoculating the new coronavirus into the young and middle-aged human body, successfully constructing a human infection model of the new coronavirus, and no serious adverse events occurred. Thanks to the dedication of many volunteers, Professor Christopher Chiu and his team answered the detailed process of the new coronavirus from entering the human body → infection → symptom relief from a new perspective.
Due to ethical issues, the sample size of this study is small, and some scientists still believe that this kind of experiment is not worthwhile compared to its risks.However, these research data can stillHere are some of the latest insights into our current pandemic prevention efforts:
① According to observation,The average incubation period is 42 hours, much shorter than the 5 to 6 days currently estimated。
②Although the virus appears in the throat earlier, the peak of the virus in the nasal cavity is much higher than that in the throat, which means there may be a higher risk of virus shedding from the nasal passages.It also emphasizedUse a mask correctly to cover your mouth and noseimportance.
③Viable virus was still detectable in some volunteers at 9 and 12 dayswhich is in line with the length of the quarantine period currently advocated.
When will the epidemic end? We want to go to the beach for a vacation, and we don’t want to grow vegetables at home.