More and more, the new crown COVID19 of unknown origin has also detected that the BA2 virus has entered the community one after another. The reporter asked:
A. The super transmission chain is in the community
In Hong Kong In a study in , using contact tracing data from 1,038 COVID-19 patients, 19% of confirmed cases were responsible for 80% of infections. The authors further found that as long as there are 4-7 super-spreader chains in the community, it will lead to 51 cluster infection events in the community.
These super-spreads take place at family gatherings, bars, weddings, temple events and other social events. And this Hong Kong study also believes that 42% of the viruses are mainly imported from abroad.
B. The increase in the immigration population
Aircraft brings more and more immigration cases. Even though border control measures are still in place, there are still “viruses that slip through the net” and enter the community. Omicron’s BA2 is the big devil that is popular all over the world. Foreign BA2 virus is very high, foreigners don’t wear masks very much, and the third dose of vaccination is not too high, not to mention Omicron’s BA2, also known as “stealth virus”. ”, which is commonly known as a screening tool, and sometimes it will be screened out accidentally…
In one study, it was shown that:
The immigration caused the community to repeatedly have sporadic cases ( Sporadic cases ) accounted for 44.2%, which was twice higher than that of the native country (21.2%).
21.6% of imported cases make the community prone to cluster infection. However, only 8.8% of the local-induced cluster infection events.
C. Asymptomatic/Presymptomatic Transmission (Asymptomatic/Presymptomatic Transmission) increased
Now the COVID19 variant virus has a strong impact on humans. There are more and more asymptomatic or mild symptoms, similar to some small cold symptoms.
Many people did not feel that they were infected during the epidemic of Omicron. They went to work, went to restaurants, and took public transportation. ..Families continue to spread the virus one by one without symptoms
Humans around the world are currently living in an invisible chain of transmission, “that chain may be in the community, or even in your room” , You won’t know, but the virus will always exist, which everyone knows for sure!
a.Ireland Study
1. Presymptomatic Transmission
Report in Ireland: [44% of transmission events], both It is from the close contact of the contact before the onset of symptoms (Presymptomatic). Most of these transmissions are family transmissions, and even during quarantine.
2. 2.6 days before symptoms and 1.4 days after symptoms
2.6 days before symptoms and 1.4 days after symptoms are both dangerous periods of transmission!
On average about 2.1-3.0 days before symptoms, the virus is already spreading. The virus is also being transmitted 1.0-1.8 days after the symptomatic bed appears.
Another study also noted that the time between the onset of symptoms, an effort to get tested, and confirmation of a positive diagnosis did not reduce transmission rates. The researchers believe that; it may be because the infection has spread long before symptoms appear.
b. USA study
1. Asymptomatic/Presymptomatic transmission (Asymptomatic/Presymptomatic Transmission )
1. Among the positive patients, 56% were asymptomatic (asymptomatic) at the time of the test, and symptoms appeared about 4 days after the test, that is, 50% had symptoms (pre-symptomatic) after diagnosis. % or so
2. CT values are very close between asymptomatic (25.5) and pre-symptomatic (23.1).
3. The results of virus culture also found that only 33% of asymptomatic patients could culture the virus, but [pre-symptomatic patients had a 71% chance of culturing the virus, which made experts think: viral load (viral load) , and the live virus, the most concentrated in pre-symptomatic patients. Accelerating this group makes it easier to spread.
D. How to deal with so many transmissions from unknown sources?
1. Maintain adequate and rapid screening
Reminder from researchers: where you live It is one of the most basic requirements for the opening of borders to have the ability to screen quickly, and a large number of incoming passengers. These common screening tools must be sufficient.
2. Newly diagnosed people entering the country will be quarantined.
All incoming passengers will have to be screened, because the concentration of the virus abroad is too high, and some places have insufficient screening tools of. In the event of a confirmed diagnosis of overseas immigrants, they must be quarantined or regulated by their own health restrictions.
3. The national vaccination rate is high enough
The study found that the national vaccination rate is still 80% to be safe. For example, there are Omicron virus antibodies all over the world, and the national vaccination rate of the third dose must be at least 80%, so that the whole people can effectively resist Omiron virus.
4. It is still necessary to wear masks
In 2022, the borders of various countries have just opened and the virus load is very high. Researchers suggest that we still need to wear masks for safety.
5. High and low risk assessment and management
Researchers suggest that Kei comes from high and low risk areas, and have you been vaccinated? Does the status assessment after a few doses go into quarantine measures, or just go into the health restriction management process? Or what kind of virus is common in the country? Do individual risk management.
6. Sufficient medical capacity can be stored
We must have sufficient medical response capacity, and can expand medical capacity at any time. Be careful that some inbound passengers may be hospitalized or even have to ICU treatment, not just simple quarantine.
