January 16, 2022

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AstraZeneca vaccines effectively reduces hospitalizations for COVID-19 in UK

AstraZeneca vaccines effectively reduces hospitalizations for COVID-19 in UK

AstraZeneca vaccines effectively reduces hospitalizations for COVID-19 in UK



 

UK experts say that AstraZeneca vaccine effectively reduces the rate of hospitalizations for COVID-19 in UK. 

 

Many countries in Europe are facing a new round of severe epidemics. Although the number of infections in the United Kingdom is relatively high, the hospitalization rate and mortality rate remain at a low level.

Some experts pointed out that the higher proportion of British people vaccinated with AstraZeneca’s COVID-19 vaccine may be one of the reasons for reducing the risk of severe illness.

 

At present, the average daily number of infections in the UK remains around 30,000, while the number of deaths is around 100.

What are the reasons? Pascal Soriot, CEO of AstraZeneca, said in an interview with the media that this is likely to be the protective effect of the T cell immune response activated by the vaccine.

When the human body is attacked by a virus, the antibody response will drive the immune system to make a defensive response immediately, while the T cell reaction time is slower, but its immunity is more durable and lasting.

 

Many people use antibodies as the evaluation criteria for vaccines, but the antibody response will continue to decline over time.

The T cell immune response in the body is relatively slow, and the human body can be infected, but most of them are not converted to severe hospitalization under the protection of the immune system.

Therefore, the number of infections in the UK is high but the number of hospitalizations is not high, and most of the hospitalized patients are unvaccinated people.

Perhaps, the COVID-19 pneumonia will not become a serious disease for vaccinators.

 

France, Germany, Belgium and many other countries early restricted AstraZeneca’s vaccination age to under 65 years old, claiming that there is no sufficient evidence to show that the vaccine is safer and effective for the elderly, while the UK has no restrictions on vaccination for the elderly.

Age restriction may be the source of the difference, and AstraZeneca’s T-cell immune response is likely to be more durable than other vaccines.

 

However, the actual immune response data of T cells has not been released, and AstraZeneca cannot determine when it will be released.

 

This seems to be more than just AstraZeneca’s boast. In April this year, experts from the University of Birmingham in the United Kingdom pointed out that researchers compared the immune response data five weeks after the first dose of AstraZeneca vaccine or other vaccines.

Different groups had similar antibody responses in the age group over 80 years old, but The T cell response of the AstraZeneca vaccine group was twice that of the other vaccine groups, and the response intensity was three times that of the other vaccine groups.

 

AstraZeneca vaccines effectively reduces hospitalizations for COVID-19 in UK

 

In mid-June, experts from the University of Oxford in the United Kingdom stated that the antibody immunity of a single vaccination of AstraZeneca vaccine will be greatly reduced after 6 months, but it can produce a strong T cell response.

 

In July, scientists from Oxford University and Switzerland stated that adenovirus vaccines such as AstraZeneca vaccine have established a “training camp” for T cells.

This protective mechanism can enter long-lived tissue cells, and these cells become T cell factories. Continuously exporting immune cells, long-term immunity may be better.

 

Eleanor Riley, professor of immunology and infectious diseases at the University of Edinburgh in the United Kingdom, believes that the initial T cell levels induced by the AstraZeneca vaccine appear to be higher than other vaccines.

These T cells are important for long-term immune memory, inhibiting virus replication, and killing infected cells after infection, which means that it can provide longer-term protection and avoid hospitalization and death.

 

However, experts from other countries have put forward different views. Experts from the University Hospital of Tubingen in Germany published a study in Nature that showed that the T cell response produced by the mRNA vaccine is stronger than that of the AstraZeneca vaccine.

A number of other real data also consistently show that the mRNA vaccine is slightly better in preventing infection and severe illness, which is inconsistent with the statement of British experts.

 

There is another explanation for the current epidemic trend in the UK. Since the UK has already launched a booster injection program, 12 million adults have now been boosted up with the third dose of vaccine.

The latest data from the National Bureau of Statistics of the United Kingdom also confirmed the immunization effect of the booster injection, and the level of antibodies in the elderly has risen again.

In contrast, many European countries only vaccinate the third dose for people at high risk of clinical infection, not all elderly people.

The final result is that the elderly in the UK are more immune to the virus, have a lower risk of severe illness, and the number of deaths is tens of thousands lower than estimated.

 

While promoting enhanced vaccination, AstraZeneca also announced the clinical Phase III results of the monoclonal antibody AZD7442, claiming that the long-acting antibody (LAAB) combination has an ideal effect in pre-exposure prevention and treatment of COVID-19 pneumonia.

 

Researchers provide pre-exposure prophylactic drugs for high-risk populations with low immunity and comorbid diseases.

During the six-month follow-up, it was found that the patients treated with AZD7442 did not experience severe illness or death, while there were 5 severe illnesses and 2 deaths in the placebo group.

It can be concluded that the use of the drug for pre-exposure prevention can reduce the risk of severe COVID-19 pneumonia by 83%.

In another therapeutic trial, researchers injected drugs into virus-infected patients within 3 days of onset of symptoms, which can reduce the risk of patients with moderate or mild disease becoming severe or death by 88%.

 

In October of this year, AstraZeneca has submitted an emergency use authorization application for AZD7442 to the US FDA. If authorized, it will supply 700,000 doses to the United States.

 

 

Reference:

1.foxnews: AstraZeneca trials show antibody drug more than 80% effective at preventing COVID-19

2. The Telegraph: AstraZeneca vaccine could be key reason why Britain is weathering the new Covid storm

AstraZeneca vaccines effectively reduces hospitalizations for COVID-19 in UK

(source:internet, reference only)


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