July 23, 2024

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Chile selects AstraZeneca COVID-19 vaccines for booster shot

Chile selects AstraZeneca adenovirus vector COVID-19 vaccines for booster shot (3rd dose)



Chile selects AstraZeneca COVID-19 vaccines for booster shot.  Chile takes the lead in selecting AstraZeneca adenovirus vector COVID-19 vaccine for immune boost. 


According to a Reuters report, Chilean President Sebastian Pinera said in a televised speech this month that studies have shown that the effectiveness of protection has significantly decreased after being vaccinated with two inactivated vaccines for several months.


In this regard, Chile will vaccinate the Oxford AstraZeneca vaccine to people who have been vaccinated with two doses of the vaccine from August 11 to strengthen the immune effect.

Chile selects AstraZeneca adenovirus vector COVID-19 vaccines for booster shot

Image source: Internet


In response to variant strains, booster immunization for the elderly and high-risk populations should be carried out as soon as possible

Currently, mutant strains of the new coronavirus are raging. Up to now, the World Health Organization has named and tracked 11 new variants, 4 of which have been listed as “Variant of Concern”. Among them, the delta strain and the lambda strain are fascinating because of their larger viral load and higher infectivity.

In the face of the Delta variant strain that spreads quickly, is more resistant to vaccines, replicates quickly in the body, and turns negative for a long time, the vaccine still has a good preventive and protective effect. Zhang Wenhong, leader of the Shanghai COVID-19 Pneumonia Clinical Treatment Expert Team, said that the solution to the virus mutation is to further expand the vaccination. Some German scholars have discovered that the sequential immunization of the COVID-19 vaccine, that is, “mixing”, may stimulate a strong immune effect and can effectively neutralize various COVID-19 virus variants. At the same time, many countries have adopted enhanced immunity as a key strategy to deal with mutant strains.

The U.S. Food and Drug Administration (FDA) is expected to develop a strategy for boosters of the COVID-19 vaccine in early September. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, said on Thursday that federal health officials are “Fastest Speed” authorizes the third dose of the COVID-19 vaccine for Americans with weaker immunity. Spain’s Minister of Health, Carolina Dalias, said that the new mutant virus is weakening the protective effects of existing vaccines, and a third dose of vaccination is needed for all citizens. Hungary announced that from August 1, people who have received two doses of the COVID-19 vaccine will receive a third booster shot.


From September, the United Kingdom will vaccinate 32 million elderly people and people with weakened immune systems with a third shot. Germany and France also announced in early August that they would provide enhanced needles from September. The UAE has also started the process of providing boosters to high-risk groups such as the elderly.

The Israeli government announced last week that it would start the third dose of vaccine for people over 60 years of age in August.

Piniella declared that the first group to be strengthened was the elderly over 55 who were vaccinated by Coxing before March 31. After that, booster immunization will be given to all the elderly and children until all target populations are covered. At the same time, the local health department will vaccinate 12 to 17-year-old teenagers, and nearly half of them have already received the first dose of vaccination. Children from 3 to 11 years old will also be vaccinated in the future.




Studies have shown that allogeneic enhancement can be more effective against the decline of vaccine protection

According to public data from the Chilean government, from February to April, the overall protective efficacy of Coxing Vaccine dropped from 67% to 58.5%. As of now, the total number of deaths due to the COVID-19 disease in the country has reached 35,806, and there are approximately 1.6 million confirmed cases. Case. At present, although the World Health Organization (WHO) has called for the suspension of booster immunization, it is recommended that people around the world complete the first vaccination first. The United States, Germany, France, Israel and other countries continue to promote booster vaccination.

The well-known medical blogger Zhuang Shilihe once said that after vaccination, the level of neutralizing antibodies has declined over time. For example, the effective rate of prevention of symptomatic infections by Kexing and Pfizer has dropped by 3%~5 compared with the beginning of June. %. The decline in the effective rate of infection prevention means that even if the vaccine is widely vaccinated, there will still be some breakthrough infections, and local outbreaks will still occur without maintaining the NPI. This provides more reference for deciding whether to boost the third dose of vaccine.

Earlier, the Chilean Ministry of Health just updated the results of a real-world study that showed that a number of COVID-19 vaccines are less effective in preventing infections with all symptoms. Data shows that 8.6 million people over 16 years of age in the local area have been vaccinated with Kexing vaccine. 14 days after the second injection, the effective rate of preventing symptomatic infection is 58.49%, the effective rate of preventing hospitalization is 86.02%, the effective rate of preventing ICU is 89.68%, and the prevention of death is The effective rate is 86.38%.

In addition, the Chilean authorities stated that 2.38 million people over the age of 16 were vaccinated with AstraZeneca’s COVID-19 vaccine. 14 days after the second shot, the effective rate of preventing symptomatic infection was 68.68%, the effective rate of preventing hospitalization was 100%, and the effective rate of preventing ICU was 100. %, the effective rate of preventing death is 100%.

In March 2021, the latest research published by the China Food and Drug Administration in the “Emerging Microbes & Infections” magazine showed that the adenovirus vector neocorona vaccine is used for booster immunization after vaccination with the inactivated vaccine, compared with the vaccination program of a single vaccine , The neutralizing antibody level is significantly increased and can produce efficient cellular immune response. This data verifies that booster immunization with adenovirus vector neocorona vaccine can break the bottleneck of the protective immune response of inactivated vaccines.


A few days ago, CanSino Bio’s Chief Scientific Officer Zhu Tao also said in a public interview that according to the clinical research on the sequential immunity of the COVID-19 vaccine initiated by Jiangsu CDC researchers, after inoculation with 2 doses of inactivated vaccine, the third dose of adenovirus vector COVID-19 The vaccine is strengthened, and the antibody level is several times different from that of the inactivated COVID-19 vaccine. After 3-6 months of inoculation with the two inactivated vaccines, the adenovirus vector COVID-19 vaccine was used to boost the antibody, and the antibody increased by about 200 times, while the inactivated vaccine increased by 30 times. The difference between the two is 7-8 times. The difference is about 5 times. One month after vaccination with a single shot of inactivated vaccine, the antibody level of the adenovirus vector COVID-19 vaccine is significantly higher than that of the complete inactivated vaccine vaccination program with 2 shots, which can be increased by 6 times.



(source:internet, reference only)

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