World Topics
Author: Lin Sihan
2021-05-04 13:12
Last update date: 2021-05-04 13:12
The South African variant that can weaken the patient's antibody and vaccine protection has been confirmed by experts and scholars to have flowed into the Hong Kong community, forming local transmission.
In India, not far from Hong Kong, the mutant virus may have spawned a second wave of epidemics like a tsunami. The number of newly confirmed cases in a single day is approaching 400,000.
How severe is the situation facing Hong Kong in the face of the menacing new crown variant virus?
Dr. Xiao Jieheng, associate professor of the Department of Medical Technology and Information Sciences of the Hong Kong Polytechnic University, accepted an exclusive interview with reporters from "Hong Kong 01" to analyze the current epidemic situation and the threat of various variants.
Since the outbreak of the epidemic, Dr. Xiao Jieheng and his team have tracked the chain of virus transmission in Hong Kong through genetic sequencing. He pointed out that the biggest threat to the Hong Kong people at present is probably the spread of the South African variant B.1.351 in the community.
On the 16th of last month, after an Indian man living in Jordan detected the virus strain, another Filipino domestic helper (without travel history) detected a virus strain with exactly the same genetic sequence.
A 29-year-old Indian male patient infected with the South African variant virus was quarantined at the Ramada Hotel in Tsim Sha Tsui.
(Photo by Liao Yanxiong)
South African variants flow into the community like a time bomb "will explode at any time"
Xiao Jieheng explained that even if patients spread two, three or even four generations, the genetic sequence may still be exactly the same. Therefore, it is impossible to determine how many generations have passed between the two patients.
"How can we find these people? Where have these people been in the community? These are the places that worry us the most."
Compared with the “Nepalese” virus strain that caused infection in Hong Kong before, the South African variant has the E484K mutation that can weaken antibody immunity. Research has found that it can break through the antibody and vaccine protection of patients with a history of infection, and the N501Y mutation makes its transmission power. It is 50% higher than the general virus and is classified as a "variant of concern" by the World Health Organization.
Since the outbreak of the epidemic, Dr. Siu Kit Hang and his Department of Medical Technology and Informatics at PolyU have tracked the chain of virus transmission in Hong Kong through genetic sequencing.
(Provided by interviewee)
"Will it become the fifth wave? This is absolutely possible." Xiao Jieheng described that the South African variant that now flows into the community "is like a time bomb, which will explode at any time."
Looking back at the dancing group in the fourth wave of the epidemic in November last year, the source of the virus strain was actually detected for the first time on October 1st last year.
"We had already held a press conference at that time and (saying) found a new virus strain to flow into the community." The first two cases of Nepalese virus strains formed a small community transmission chain, but because the chain of transmission could not be resolved at that time, "Who knows Whenever we encountered a dancing group, there was a big explosion, leading to the fourth wave of the epidemic until today, we are slowly getting out of it."
On April 30, the closed area of Block 11 of Yingwan Garden, Tung Chung was tested, and 400 residents had to be evacuated for quarantine for 21 days.
(Photo by Liang Pengwei)
India and UK variants or reduced vaccine efficacy
Another worrying Indian variant, B.1.617, has neither the E484K mutation, which reduces the immune function of antibodies, nor the N501Y mutation, which enhances transmission.
But instead, there are two mutations that are expected to weaken antibody immunity.
Among them, E484Q and E484K have the same location, and computer analysis predicts that the functions of the two are also similar.
The other mutation, L452R, is located at the location where the antibody attacks the virus in the human body. "If there is a mutation here, the situation is like E484Q, so that the neutralizing antibody cannot effectively bind to the virus and the virus can escape." When the two mutations are added together, the protection of the vaccine may be a double whammy.
However, Xiao Jieheng added that the relevant theory has not yet been supported by substantive scientific evidence, so the WHO currently only regards it as a "variant under investigation" (variant under investigation).
In addition, Xiao Jieheng reminded that the British variant B.1.1.7 has also recently been found to have E484K mutations (previous mutations such as N501Y and P681H mainly enhance the transmission of the virus), so it may become like the South African variant to weaken antibody immunity.
AstraZeneca vaccine is favored by low- and middle-income countries because of its low price, but it may be difficult to resist the South African variant.
(AP)
Entry quotas need to be reviewed, genetic sequencing needs to be strengthened
In the face of menacing variants, Xiao Jieheng believes that the most important thing is the no-fly. The government's current no-fly fuse mechanism and the indefinite suspension of Indian flights are all correct measures.
However, it is not only the origin of the virus that needs to be guarded, the government needs to review the daily entry quota as a whole.
"We are now in a peaceful and prosperous age, but you see (the epidemic) rebounding everywhere."
Last Tuesday (April 27) South Korean health authorities announced that a total of 86 cases of variant viruses including the United Kingdom, South Africa, and Brazil were confirmed in the past week, of which 52 were local cases; the Japanese government announced on Monday (April 26) Japan) said that 21 cases of Indian variants were detected; and the Ministry of Health of Singapore also said last week that 7 cases of British variants and 1 case of South African variants were confirmed-"When the surroundings are rebounding, we (are in a situation) are actually at high risk. "
A foreign domestic helper in Block 11, Caravan Park, Ocean View, Tung Chung was diagnosed with a variant of the new crown pneumonia virus. Several locations in Tung Chung were subject to mandatory testing. On May 1, a large number of Tung Chung residents and foreign domestic helpers were tested at Tung Chung Station in a row Long long, waiting for testing.
(Provided by readers)
Xiao Jie Hang Seng Index, if you look back at the third or fourth wave of the epidemic, you will find that there has been an increase in the number of single-day imported cases before the local epidemic intensified.
Once the number of imported cases exceeds 20, it is a dangerous "signal" for the Hong Kong government, and the mutant virus "has a chance to break through the line of defense and flow into the community."
He explained that as the first line of defense against epidemics, isolated hotels are clearly inferior to hospitals in terms of quarantine and sanitary conditions. The influx of cases into the community is "not surprising at all" and "will happen sooner or later."
In addition, if the government can expand the scale of gene sequencing work, it will also be of great help in cutting the chain of virus transmission.
Assuming that there are really cases that have flowed into the community, based on the genetically sorted database, you can quickly know which imported case has the most genetically matched virus strain, and you will not find a case that has flowed into the community like this time.
Xiao Jieheng said that actual gene sequencing is not part of the conventional epidemic prevention countermeasures. Due to cost and time, the Health Protection Center will not sort every case. As for several university laboratories, they do some gene sequencing work. But the samples may be duplicates, some samples or no one did it at all.
If at the critical moment, the Department of Health and the university laboratories can systematically divide the labor, they can detect the related cases as soon as possible to track and cut the chain of transmission.
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