BA.5 officially invades the Taiwan! "Nature" reveals 3 major features: strong communication power may be "unprecedented"
BA.5 officially invades Taiwan! “3 characteristics” may cause the chain of transmission to continue to expand
According to the Central Epidemic Command Center, Taiwan currently has two locally confirmed cases of Omicron virus subtype “BA.5”. Will the new variant virus cause a serious epidemic? According to American virus evolutionary biologist Jesse Bloom, compared with previous Omicron subtypes such as BA.1, BA.2 or BA.3, its descendants BA.4 and BA.5 seem to be better able to evade antibodies and immune responses; even though People have been infected with the new coronavirus before, and BA.5’s strong immune escape ability may still cause illness, causing “secondary infection.”
An article published in the authoritative journal “Nature” pointed out that BA.4 and BA.5 are the latest members of the Omicron family tree. They were first discovered by South African scientists in April and quickly began to spread in dozens of countries around the world. Now, according to the WHO report, BA.4 and BA.5 have accounted for 55% of global COVID-19 cases, with approximately 4.1 million people infected and the virus having spread to 110 countries.
Research published in “Nature” also mentioned that in addition to high transmissibility and strong immune evasion, BA.4 and BA.5 also showed similar ACE2 binding ability to previous generations of viruses. Monoclonal antibody drugs such as NAb, Bebtelovimab and Clgavimab have the same effect of neutralizing viruses, but booster vaccines designed based on BA.1 may be less effective against BA.4 or BA.5 and cannot target future emergence. variants achieve broad protection.
BA.5’s powerful communication power is “unprecedented”? Intensivist: R0 value reaches record high
How can we know that BA.5 is spreading faster than before? Dr. Huang Xuan, an expert in critical care medicine, pointed out that the R0 value (Basic Reproduction Number) stands for “Basic Infection Number or Basic Reproduction Number”, which is a value used to evaluate how many people a confirmed person can infect from the time of infection to recovery or death. . A large R0 value does not mean that the virus is more virulent, but that the faster the virus reproduces and the more contagious it is, the more difficult it is to control the spread of the epidemic.
Dr. Huang Xuan said that generally speaking, if the R0 value exceeds 10, it means that the spread of the epidemic is quite severe. The R0 value of the new coronavirus original strain is 3.3, ALPHA is 4.5, DELTA is 5.1, OMICRON-BA.1 is 9.5, BA.2 is 13.3, and BA.4/5 is 18.6. It shows that the R0 value of the virus is indeed rising, and as long as the virus has mutated genes, new mutated viruses will appear, and their transmissibility will be wider and stronger.
Japanese experiment: BA.5 may be more deadly than its predecessor! Will second-generation mRNA vaccines be the answer?
In addition to concerns that BA.5 will cause a larger-scale epidemic, the scientific community also generally believes that the effectiveness of the new coronavirus vaccine will be reduced against the latest mutant viruses. “Cell Host & Microbe” published a study indicating that those who had received three doses of the vaccine did have stronger neutralizing antibodies against BA.2; however, for variants such as BA.2.12.1, BA.4 and BA.5, The degree is lower than that of the first generation BA.1 and BA.2.
In addition, according to animal experiments in Japan, BA.4 and BA.5 are transmitted among hamsters, are more lethal than BA.2, and may cause greater damage to lung cells. Sato, the study author and a virus expert at the University of Tokyo. Qing warned that we should not take it for granted that the new coronavirus will weaken and become influenza. Just because the virus is more transmissible does not mean that it is less virulent. People still cannot take it lightly.
Christian Althaus, an epidemiologist at the University of Bern in Switzerland, said that it is still unclear when the next variant will appear. BA.4 and BA.5 began to spread in South Africa just a few months after BA.1 and BA.2, and this pattern is currently being repeated in Western countries such as the United Kingdom and the United States. As vaccines become more widely available around the world and immunity to COVID-19 infection increases, Althaus expects the frequency of COVID-19 transmission to slow.
A press release issued by the WHO on June 28 stated that even though the virus mutates rapidly, the update and development of vaccines still have significance. BioNTech is currently working with Pfizer to develop a second-generation vaccine (pan-coronavirus vaccine), which is expected to be authorized as soon as the end of this year. WHO also calls on the public to get vaccinated as soon as possible to gain protection; without the neutralizing antibodies of the vaccine, Omicron may still cause a certain probability of severe illness and mortality.
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