The latest vaccine research of Pfizer Pharmaceutical Co., Ltd. of the United States (Pfizer) and German Biotech Company (BioNTech) shows that their specially modified vaccine boosters for the new coronavirus variant strain Omicron (Omicron) can produce More immune responses, up to 19 times more effective.
Screenshots of related reports
Pfizer and BioNTech According to a Phase II/III trial involving 1,234 people aged 56 or above, participants received the fourth dose of the monovalent vaccine developed by Omicron, and received 30 micrograms and 60 When people with a microgram dose were exposed to Omicron BA.1, the geometric mean titer (GMT) of antibodies in their bodies increased by 13.5 and 19.6 times respectively compared with before vaccination.
Hong Kong expert Kong Fanyi, a member of the COVID-19 Expert Advisory Committee and a clinical professor at the Department of Internal Medicine at the University of Hong Kong, believes that whether the vaccine is effective or not still needs to be reviewed with detailed data. If it is approved for use in Hong Kong in the future, the elderly and chronically ill should be vaccinated first, and then For the sake of medical care, vaccination was finally opened to all people.
asked: How to get a booster shot?
Pfizer and its partner BioNTech are studying two different approaches to updating the vaccine - one that targets only the Omicron variant, or a combination booster (bivalent vaccine) that adds Omicron protection to the original vaccine; another One option is to maintain the current standard dose of 30 micrograms, or double the dose (monovalent vaccine).
In a study of more than 1,200 middle-aged and elderly people who had received three doses of the vaccine, Pfizer said that both methods of boosting immunity successfully stimulated a substantial increase in Omicron antibodies in the body. Pfizer's booster dose, which targets only the Omicron variant, triggered the strongest immune response.
However, many experts say combination vaccinations may be the best approach because they will retain the proven benefits of the original COVID-19 vaccines while adding new protection against Omicron.
asked: What are the constraints to the new vaccine?
However, such a powerful new vaccine still has its limitations. According to Reuters , a study published in the journal "Nature" on June 17 showed that vaccine boosters based on the BA.1 virus "may not achieve broad-spectrum protection against new Omicron variants" , and specifically cited this example. The vaccine being developed by Pfizer/BioNTech.
Reuters reported on June 18 that "early Omicron antibodies may be ineffective against current variant viruses"
According to the latest reports, the new vaccine can actually enhance the immune response when faced with BA.4 or BA.5 but the response is slower BA.1 is lower than , with a difference of about 3 times. In the next few weeks, pharmaceutical companies will continue to collect data on BA.4 or BA.5 for continued research.
asked: What are the infectivity and immune escape characteristics of BA.4 and BA.5?
It is understood that the two subtype mutant strains, BA.4 and BA.5, are indeed more transmissible. Compared with BA.1 and BA.2, the transmissibility of BA.4 and BA.5 may increase by 20% to 30%, but this difference will not be as serious as the "double increase" from Delta to Omicron. However, BA.4 and BA.5 are more transmissible in human bronchial and alveolar cells, which means is more pathogenic. .
In addition, in terms of immune escape characteristics, many foreign papers have confirmed that the two subtype mutant strains, BA.4 and BA.5, are resistant to antibodies after BA.1 and BA.2 infection, and even A research report points out that after three doses of the vaccine, the titers against the two subtype mutant strains BA.4 and BA.5 are lower. Therefore, once becomes the mainstream virus strain in the future, it will have a high chance of causing more There are many breakthrough infections , and countries still need to monitor closely and not take it lightly.
(Editor: Zhuang Shu)
This article is a new media article from Hong Kong's "Economic Herald".
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