Những điều cần biết về COVID-19

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"Hỗn chiến": chống "nhiều màu". Kháng thể nhiều gấp 10 lần.

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COVID: Are mix-and-match vaccines the way forward?

A new German study reports that a combination of the AstraZeneca and BioNTech vaccines triggers a remarkably stronger immune response than sticking with one kind of shot.


Does it make more sense to switch to BioNTech after the first AstraZeneca shot?

Following its approval from the European Medicines Agency in January, the AstraZeneca vaccine against COVID-19 was administered to all adults in Germany. After discovering that especially younger women who received the shot faced an increased risk of dangerous blood clots in the brain, however, Germany's Standing Committee on Vaccination (Stiko) in April recommended limiting use of AstraZeneca to people over 60.

That meant quite a few people who had received their first dose of AstraZeneca had to then get BioNTech-Pfizer or Moderna for their second shot. Today, all adults in Germany, no matter their age, can be vaccinated with AstraZeneca again, if the patient and doctor have a conversation about the risks prior to the jab.

But a new study shows that combining two different vaccines might be more valuable than just an emergency solution. Researchers at Saarland University in western Germany have found that people whose first shot was AstraZeneca and whose second shot was BioNTech-Pfizer showed an immune response stronger than that in patients who had received two doses of the same vaccine.

So ― is it time to switch the world's immunization approach to a mix-and-match vaccination for everyone?

Not quite yet.

Preliminary results

The findings coming out of Saarland University are preliminary and have not yet been fully evaluated scientifically, the university emphasized in the press statement sharing the results. Before the researchers officially publish their findings, they will look into the role played by the age and gender of the patients, for example, and also delve deeper into which combinations can potentially trigger more severe side effects.

Even though a full data evaluation hasn't been completed yet, the team conducting the study was surprised by the clear results.

"That's why we wanted to share our outcomes now and not wait for the scientific evaluation process to be completed," Martina Sester, professor for transplantation- and infectional immunology at Saarland University, said in the press statement.

Ten times the antibodies

There were 250 people that participated in the trial conducted at the University Hospital in Homburg, Saarland, over the last few months. Some of them received two AstraZeneca shots, some received two BioNTech-Pfizer shots and a third group received an AstraZeneca shot followed by one from BioNTech.

The researchers compared the strength of participants' immune responses two weeks after the second shot. "We didn't just look at the number of antibodies against the coronavirus [the participants] developed, but also how effective the so-called neutralizing antibodies were," Sester explained. "That tells us how good the antibodies are at preventing the virus from entering our cells."

In terms of antibody development, the double-BioNTech as well as the combined AstraZeneca-BioNTech vaccination was significantly more effective than the double-AstraZeneca alternative. Participants who had one of the first two combinations of shots produced around 10 times more antibodies than those with two AstraZeneca jabs. And looking at the neutralizing antibodies, results with the mix-and-match vaccine approach were "even slightly better" than those achieved with two BioNTech shots, Sester said.

For vaccines that require two jabs, health officials have typically recommended the second shot be the same as the first. Since there were no changes in regulatory recommendations for the BioNTech vaccine, there are few known cases of people receiving a BioNTech-Pfizer shot before an AstraZeneca shot.

'Remarkable' boost in antibody production

The Spanish CombivacS trial, conducted with 663 participants at the Carlos III Health Institute in Madrid, came to a similar conclusion. The study's preliminary results were reported in the scientific journal Nature. Like the results from Saarland University, they are not yet final ― the publication in Nature is an overview of what the researchers in Spain have found so far, and not a full, peer-reviewed article.

Two-thirds of participants received a shot of the BioNTech-Pfizer vaccine after their initial AstraZeneca jab. The last third had not received a second shot at the time the initial results were shared. Magdalena Campins, an investigator on the CombivacS study at the Vall d’Hebron University Hospital in Barcelona, reported that those who had received the full mix-and-match vaccine combination began producing much higher levels of antibodies after their second shot, and these antibodies were able to recognize and inactivate SARS-CoV-2 in laboratory tests.

"It appears that the [BioNTech-]Pfizer vaccine boosted antibody responses remarkably in one-dose AstraZeneca vaccines," said Zhou Xing, an immunologist at McMaster University in Hamilton, Canada, who was not involved in the study, in the Nature article. Xing added that the boost appeared to be even more pronounced than the one in people who had received their second dose of the AstraZeneca vaccine.

However, aside from the fact that its results aren't yet finalized and peer-reviewed, one problem with this study out of Spain is that it doesn't include a control group of people who received two shots of the same vaccine — so no direct comparison between the two groups was possible.


So far, a little less than one quarter of Spain's population is fully vaccinated against COVID.

Vaccine combination 'should be seriously considered'

If the initial results are anything to go by, the combination of AstraZeneca and BioNTech-Pfizer appears to be a promising way to immunize people against COVID.

That's not because the two vaccines are in any way similar, though. They represent two types of COVID vaccines currently on the market.

The AstraZeneca shot is a traditional vector vaccine. It uses a harmless version of a different virus to deliver instructions to human cells, which learn to build up antibodies against the coronavirus.

The BioNTech jab is an mRNA vaccine, a new kind of immunization method. MRNA vaccines teach human cells how to make a protein that in turn triggers an immune response and the production of antibodies.

Researchers don't yet have enough information to know why the combination of these two vaccines can result in boosted immunity. Saarland University professor Sester said she was looking forward to seeing more research done on combining different types of vaccines and how they interact. "We believe that if other research teams reach conclusions similar to ours, the combination of vector- and mRNA vaccines should be seriously considered," she said.

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[Triển]

"Hỗn chiến": chống "nhiều màu". Kháng thể nhiều gấp 10 lần.

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Kết luận: nếu đã chích một thứ, lần sau nếu được chọn lựa, chơi phá cách cho nó oách: chọn thuốc khác!

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"loooooong covid" - Hệ lụy

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Pfizer/BionTech 96%, AstraZenecca 92% hiệu quả chống Delta...
không bị nhâp viện. Không trở nặng đi nhà thương.

Thuốc nào thì thuốc, đều phải chích 2 liều mới hiệu nghiệm.

J&J và Moderna dường như chưa có khảo sát nào trước Delta.
Hi vọng là cũng có tác dụng. Delta đang dày vò nước Anh. Chỉ
còn là vấn đề thời gian khi nào các quốc gia Châu Âu "nhuộm"
màu Delta mà thôi.

Nhưng nói đến số phần trăm hiệu quả thì vẫn còn số phần trăm
không hiệu quả. 100 người chích đủ 2 liều Pfizer/BionTech
thì có đến 4 người sau đó vẫn có thể bị nhiễm Delta....nặng.
100 người chích đủ 2 liều AstraZenecca thì vẫn còn 8 người có
thể bị nhiễm Delta và trở nặng.

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UK study finds vaccines offer high protection against hospitalisation from Delta variant

LONDON, June 14 (Reuters) - COVID-19 vaccines made by Pfizer (PFE.N) and AstraZeneca (AZN.L) offer high protection of more than 90% against hospitalisation from the Delta coronavirus variant, a new analysis by Public Health England (PHE) showed on Monday.

Prime Minister Boris Johnson is expected to announce a delay to the lifting of COVID-19 restrictions in England due to the spread of the highly transmissible Delta variant of concern, first identified in India, which is also associated with a higher risk of hospitalisation among the unvaccinated.

PHE said that the Pfizer/Biontech COVID-19 vaccine was 96% effective against hospitalisation from the Delta variant after two doses, while Oxford/AstraZeneca's offered 92% protection against hospitalisation by Delta.

PHE said that those levels of protection were comparable to that against the Alpha variant, first identified in Kent, southeast England.

The analysis adds to evidence that, although the Delta variant reduces the effectiveness of vaccines against symptomatic infection, two doses of COVID-19 vaccine still protect against severe disease.

"These hugely important findings confirm that the vaccines offer significant protection against hospitalisation from the Delta variant," said Mary Ramsay, Head of Immunisation at PHE.

The PHE findings follow a Scottish study which showed that two doses of a COVID-19 vaccine among people who tested positive cut their risk of hospitalisation by 70%, although there were not enough hospital admissions reported to compare the vaccines.

PHE said that while further work was being undertaken to establish the level of protection against mortality from the Delta variant, levels of protection against death were expected to be high.

Reporting by Alistair Smout; editing by Michael Holden

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[Triển]

- Có thể du lịch vòng quanh thế giới được chưa?
- Chưa, còn lâu lắm.

- Vượt qua đại dịch chưa?
- Chưa, còn lâu lắm.

- Sao người ta nói mấy nước giàu đã ổn định vụ bệnh dịch covid-19 rồi?
- Nói dóc.
- Tại sao?
- Muốn có vụ cộng đồng miễn nhiễm cần tới 75% dân số chích ngừa đầy đủ. Thống kê hiện tại có rất ít quốc gia làm được chuyện này. Những quốc gia làm được: không phải là quốc gia giàu có mà là các quốc gia ít dân. Ví dụ: nước Gibraltar đã chích ngừa 100% dân số của mình. Dân số của Gibraltar chỉ có hơn 33 ngàn dân.




(* nguồn: https://ourworldindata.org/covid-vaccinations )

[Triển]

Pfizer/BionTech 96%, AstraZenecca 92% hiệu quả chống Delta...
không bị nhâp viện. Không trở nặng đi nhà thương.

Thuốc nào thì thuốc, đều phải chích 2 liều mới hiệu nghiệm.

J&J và Moderna dường như chưa có khảo sát nào trước Delta.
Hi vọng là cũng có tác dụng. Delta đang dày vò nước Anh. Chỉ
còn là vấn đề thời gian khi nào các quốc gia Châu Âu "nhuộm"
màu Delta mà thôi.

Nhưng nói đến số phần trăm hiệu quả thì vẫn còn số phần trăm
không hiệu quả. 100 người chích đủ 2 liều Pfizer/BionTech
thì có đến 4 người sau đó vẫn có thể bị nhiễm Delta....nặng.
100 người chích đủ 2 liều AstraZenecca thì vẫn còn 8 người có
thể bị nhiễm Delta và trở nặng.

Hãng J&J của Mỹ có vô Đặc Trưng đọc bài.
Có hiệu quả 88%. Nghĩa là 100 người chích ngừa thuốc J&J
thì sẽ có 88 người không bị nặng và nhập viện. 12 người còn lại là "hên xui".

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Coronavirus digest: J&J says vaccine effective against delta variant

J&J's data showed the immune response lasted for at least eight months, and could prevent serious illness and hospitalization. The company said the immune response improves over time. Follow DW for the latest.



Johnson & Johnson said Thursday its vaccine generated strong and persistent activity against the delta and other prevalent coronavirus variants.

The company said its data showed the immune response lasted at least eight months. The vaccine showed 85% efficacy, and could prevent serious illness and hospitalization.

"Current data for the eight months studied so far shows that the single-shot Johnson & Johnson COVID-19 vaccine generates a strong neutralizing antibody response that does not wane; rather, we observe an improvement over time," said a company statement.

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"Ngừa lai giống": Bộ trưởng y tế Đức, xúi dân chích phối hợp, mũi đầu AstraZenecca thì mũi sau BioNTech-Pfizer hoặc là Moderna để gia tăng hiệu quả chống con Delta.

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German Health Minister Jens Spahn urged people to get fully vaccinated in order to contain the spread of the delta variant.

Data from the Robert Koch Institute (RKI) suggested that the delta variant now made up around half the cases in Germany. "It's up to us whether delta gets a chance," said Spahn.

Authorities from Germany's vaccine committee have advised people who got the first dose of the AstraZeneca vaccine to mix it up with a second dose of the BioNTech-Pfizer or Moderna vaccine for better protection.

The committee said studies showed the immune response was "clearly superior" when an AstraZeneca shot is combined with a second mRNA vaccine.

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Delta lan tràn, Pfizer-BioNTech thêm dịp tiếp tục hốt bạc: "liều tăng cường"

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Biến thể Delta lan rộng, Pfizer-BioNTech xin cấp phép cho liều tăng cường phòng COVID





Pfizer và đối tác BioNTech dự định yêu cầu các cơ quan quản lý của Hoa Kỳ và châu Âu trong vòng vài tuần tới cho phép tiêm liều tăng cường vaccine COVID-19 của hãng, dựa trên bằng chứng về nguy cơ lây nhiễm cao hơn sau 6 tháng tiêm chủng và tình trạng dễ lây lan của biến thể Delta, theo Reuters.

Tuy nhiên trong một tuyên bố chung, Cục Quản lý Thực phẩm và Dược phẩm (FDA) và Trung tâm Kiểm soát và Phòng ngừa Dịch bệnh Hoa Kỳ (CDC) nói rằng những người Mỹ đã được tiêm chủng đầy đủ không cần phải tiêm mũi tăng cường COVID-19 vào thời điểm này.

Một số nhà khoa học cũng đặt câu hỏi về sự cần thiết của việc tiêm tăng cường.

Cơ quan Dược phẩm châu Âu không trả lời yêu cầu bình luận của Reuters.

Giám đốc khoa học của Pfizer, Mikael Dolsten, cho biết hiệu quả sụt giảm của vaccine được báo cáo gần đây ở Israel chủ yếu là do lây nhiễm ở những người đã tiêm vaccine vào tháng Giêng hoặc tháng Hai. Bộ Y tế nước này cho biết hiệu quả của vaccine trong việc ngăn ngừa lây nhiễm và nhiễm bệnh có triệu chứng đã giảm xuống còn 64% vào tháng Sáu.

“Vaccine Pfizer có hoạt tính cao chống lại biến thể Delta”, Reuters dẫn lời ông Dolsten cho biết trong một cuộc phỏng vấn. “Nhưng sau 6 tháng, có thể có nguy cơ tái nhiễm khi các kháng thể, như đã được dự đoán, sẽ bị suy yếu”. Ông cho biết các dữ liệu sẽ được đệ trình lên FDA trong tháng tới.

Pfizer không công bố toàn bộ dữ liệu của Israel hôm 8/7, nhưng cho biết các dữ liệu này sẽ sớm được công bố.

“Đó chỉ là một tập hợp dữ liệu nhỏ, nhưng tôi nghĩ khuynh hướng là chính xác: Sáu tháng đã qua, mà Delta là biến thể dễ lây lan nhất mà chúng tôi từng thấy, nó có thể gây lây nhiễm và bệnh nhẹ”, ông Dolsten cho biết.

Trong tuyên bố chung, FDA và CDC nói: “Chúng tôi đã chuẩn bị cho các liều tăng cường trong trường hợp nếu và khi khoa học chứng minh rằng chúng là cần thiết”.

Ông Dolsten nhấn mạnh rằng dữ liệu từ Israel và Anh cho thấy ngay cả khi mức độ kháng thể suy yếu, vaccine vẫn đạt hiệu quả khoảng 95% đối với bệnh nặng.

Vaccine, do BioNTech của Đức phát minh ban đầu, đã cho thấy hiệu quả 95% trong việc ngăn ngừa triệu chứng COVID-19 trong một thử nghiệm lâm sàng mà các công ty đã thực hiện vào năm ngoái.

Ông Dolsten cho biết dữ liệu ban đầu từ các nghiên cứu của công ty cho thấy liều tăng cường thứ ba tạo ra mức kháng thể cao hơn từ 5 đến 10 lần so với sau khi tiêm liều thứ hai. Điều này cho thấy liều thứ ba sẽ mang lại hiệu quả bảo vệ đầy hứa hẹn.

Ông cho biết nhiều quốc gia ở châu Âu và những nơi khác đã tiếp cận Pfizer để thảo luận về liều tiêm tăng cường này và một số có thể bắt đầu sử dụng chúng trước khi có sự cho phép của Hoa Kỳ.

Ông Dolsten nói ông tin rằng mũi tiêm tăng cường đặc biệt quan trọng ở các nhóm cao tuổi.

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Almost half of UK COVID infections are in people who are at least partly vaccinated, study suggests. But the cases were much milder.
Marianne Guenot
17 hours ago


A woman receives the COVID-19 vaccine in Wales, UK. Matthew Horwood/Getty

Almost half of COVID-19 cases in the UK are among people who are partly or fully vaccinated people, according to data from a large study.

The finding came from the ZOE COVID Study run by King's College London. It uses information logged daily by over a million people to predict COVID-19 trends

As of July 15, an estimated 17,581 new daily UK cases of COVID-19 were in unvaccinated people, the study authors said in a press release on Thursday.

That compares to an estimated 15,537 new COVID-19 cases in people who had at least one dose of the vaccine, which is about 47% of all cases.

"That's probably because the virus is just running out of people to infect who haven't already been exposed and don't have natural immune unity in those groups [unvaccinated people]," Prof Tim Spector, an epidemiologist from King's College London, said in a video accompanying the press release.

Spector is the lead author of the ZOE COVID Study.

People who have had only one dose of the vaccine are less protected against mild symptoms of COVID

COVID-19 is spreading more quickly in those who have received only one dose of vaccines, as can be seen in the graph below from ZOE's data:


Rate of positive COVID-19 tests in the UK by vaccination status among Zoe COVID Symptom Study participants. Zoe COVID Symptom Study/Insider

In an email to Insider, Spector said: "Our research showed fewer, milder symptoms were reported in vaccinated people compared to unvaccinated adults who had contracted the virus."

This aligns with other data suggesting that two doses provide the best protection from the Delta variant, and the one dose gives significantly less, but is better than nothing.

According to figures from Public Health England (PHE), one dose of AstraZeneca or Pfizer vaccine reduced the risk of catching mild symptoms of COVID-19 by 35%.

However, even one dose of vaccine protects against the more severe risk of COVID-19, reducing the risk of hospitalization by 80%.

Two doses of vaccine were much more protective, reducing the risk of having mild symptoms of the disease by about 80%, and the risk of hospitalization by 96%, the PHE data said.

Preliminary data from ZOE also suggests the risk of long COVID is also substantially reduced by two doses of vaccine, Spector told Insider.

Cases seem to be plateauing in unvaccinated — a good signal

Cases in unvaccinated people were estimated to be 22% lower than the previous week, while cases in vaccinated people rose by 40%. This suggests the wave in the unvaccinated population has now peaked in the UK, the study authors said in the press release.

Hospitalization rates in the UK have risen slightly, with 3,615 new COVID patients in the hospital as of July 14, compared to about 900 in May.

Cases continue to rise driven by the Delta variant. "It is my belief that as more people in the UK receive their second vaccination, hospitalizations will stabilize and likely fall," Spector told Insider in an email.

Spector told Insider that the figures should be taken with a grain of salt, as there are fewer ZOE app contributors that are now unvaccinated.

"We will monitor cases closely in the next few days in order to confirm the peak."

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[Nhã Uyên]

Các biến thể của virus SAR-COV-2 gây bệnh Covid-19



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