Why the bad news of the AstraZeneca vaccine is an obstacle to the exit from the epidemic

Why the bad news of the AstraZeneca vaccine is an obstacle to the exit from the epidemic

But that doesn’t mean that governments should get rid of AstraZeneca stocks. Experts say it is possible – and very likely – that the shot is still effective in preventing severe disease and death.

However, the news may be a major obstacle to the world’s way out of the pandemic, which cannot be “ over ” until the widespread virus stops spreading.

Oxford-AstraZeneca is cheaper, easier to transport and store than some of the other vaccines approved for use thus far, and as such, it would have played a major role in fighting the epidemic in low- and middle-income countries. If the vaccine is not effective enough against the new variant, it could deepen an already huge vaccination gap between the world’s richest and poorest countries.

The study has not yet been fully peer-reviewed or published, and much unknown remains. What we do know is that it included a relatively small number of volunteers who were predominantly young and healthy, and thus unlikely to suffer from severe Covid-19 disease. This means that the study did not assess protection from severe disease, hospitalization and death, and many experts indicated that it could still prevent these outcomes.

“In the medium term, what matters most is preventing more severe forms of Covid-19; it is believed that the AstraZeneca vaccine will do so,” Dr Peter English, an infectious disease control consultant, told the UK Media Center.

A new vaccination strategy

Less effective vaccines may force countries where new variables become dominant to change their vaccination strategy.

Rather than trying to achieve herd immunity, the focus may be on preventing as many deaths as possible even while the virus continues to spread.

South Africa stop AstraZeneca vaccine rolled out after the study released Sunday.

Speaking to CNN, Professor Salem Abdel-Karim, who is the co-chair of the Covid-19 Advisory Committee in South Africa, said the country would likely adopt a “stepwise approach”, in which they would assess the effect of the vaccine during rollout. Outside.

“We will start vaccinating about 100,000 people in the first step. We will look at hospitalization rates once we finish those vaccinations. And if we find that hospitalization rates are below the threshold – we are looking at – then we can be confident that the vaccine is effective … and if that is the case. Then, we can proceed to continue rolling out the vaccine. ”

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“If we find that hospitalizations are large – more than we expected – we will have to stop, assess where we are and perhaps switch to other vaccines.”

But the AstraZeneca vaccine is an essential part of the mass vaccination programs in many countries around the world.

The UK has been running it since last month, and the government said on Monday that it will continue to use it. While the UK is one of at least 41 countries in which the South African variant has been detected, the number of cases it causes is still very low. But the mutation in the South African variant – known as the E484 mutation – was also present Found independently In samples from A variant first seen in the UK.
The European Union has also approved the vaccine, despite the approval of many European countries It is advised not to use it in the elderly Due to the limited effectiveness data in that age group.

The COVAX program – a coalition that includes Gavi and the World Health Organization with the goal of distributing Covid-19 vaccines to poor countries – is based on this vaccine. Last week, COVAX announced a plan to distribute more than 337 million doses worldwide – of which 336 million doses are the AstraZeneca-Oxford vaccine and 1.2 million doses of the Pfizer-BioNTech vaccine.

Experts from COVAX said on Monday that the WHO’s Strategic Expert Advisory Group is finalizing new recommendations for the use of the AstraZeneca vaccine and will present them to the director-general on Tuesday.

Other coronavirus vaccines have shown more hope against the new variants. Real-life trials of some other vaccines, including Johnson & Johnson And the Novavax, Show some protection against new variants. Pfizer-BioNTech and Moderna also said their vaccines should be effective against the new variants, although their data is based on Laboratory studies Instead of realistic experiences.

South African health officials said they hope to receive the first doses of the Johnson & Johnson vaccine by the end of the week. The country has also ordered another 20 million vaccines through a deal with Pfizer / BioNTech, but it is not clear when those doses will arrive.

However, the AstraZeneca vaccine would be, at least initially, the most accessible option for many countries.

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Reducing the burden on health services

The role of the vaccine is to teach the immune system to quickly detect and fight the virus. Basically, it helps the body remember an infection so that it works faster if you do get infected. “Your immune system will also react to get rid of the virus, but without the vaccine, this reaction will be slower,” said Dr. Julian Tang, associate professor emeritus and clinical virologist at the University of Leicester.

The currently available coronavirus vaccines work by stimulating antibodies and T cells that have been shown to fight the original coronavirus. Antibodies work by attaching to and attacking proteins on the surface of the virus – in the case of the Coronavirus, this is the spiky protein.

Tang explained that if the virus changes a lot, especially in the spike protein, the antibodies caused by the vaccine may not bind to the new version of the virus well.

He added, “This means that these vaccine antibodies cannot remove many of these viruses when you are infected, so there are more viruses left that need to be eliminated through your immune response – which reacts more slowly.”

The study shows that the AstraZeneca vaccine significantly reduces the transmission of the coronavirus

“But studies indicate that there is a sufficient correlation of these vaccine antibodies to remove at least some of the variable viruses from the system – to prevent more severe disease and death.”

One of the main causes of death from the pandemic is the sheer number of people who need medical care, and a partially effective, if not perfect, vaccine would reduce this burden.

There have been instances where healthcare systems have become unable to handle the number of incoming patients. And when this happens, some patients may die because they cannot get help on time. There is also an indirect effect on the entire system, with non-urgent treatments postponed or canceled.

Experts argue that the vaccine would prove beneficial if it could reduce the burden on health services.

“This might sound like fewer people need a bed in the ICU and more people are able to recover at home,” said Dr. Oliver Watson, an infectious disease researcher at Imperial College London, adding that this could have “real physical consequences in the world.” The places where the hospitals are located … have expanded too. ”

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This was the case in several European countries, including the United Kingdom, where the government had to open several field hospitals to prevent the national health system from collapsing.

Modify the vaccine

There is no doubt that the data from South Africa represents a setback for the vaccination campaigns, but scientists are already working on updates to the existing vaccines to make them more effective against the new variants.

AstraZeneca said Saturday that it is working with the University of Oxford to adapt the vaccine against the B.1.351 variant and that it will work to advance it through clinical development to make it “ready for delivery in the fall if needed”. Last month, Pfizer said it was “laying the groundwork” for creating an enhanced vaccine that can respond to variants of the Coronavirus.

“We see this all the time with the flu shot,” Tang said. Flu vaccines are adapted each year to target the most common strains of the virus. Sometimes, the vaccine chosen does not match the dominant strain.

“Non-matched vaccine seasons allow for more flu cases, morbidity and deaths – but to some extent, this is inevitable because the virus will always mutate first – then we will have to adjust our vaccines to match the new virus,” Tang added. .

British Health Secretary Matt Hancock said on Monday that the flu scheme may work with the coronavirus in the future.

“The vaccine is updated every year according to the mutations and changes that have occurred and been observed in the past few months. It is manufactured during the summer, and then delivered to the arms of people most at risk of contracting the flu in the fall.,” He said.

When it comes to Covid-19, he made clear that we need to think about how to protect people in a similar way.

The good news is that developing a vaccine that will work against new variants doesn’t mean starting from scratch, so updates may become available soon.

“The variable protein genome is known, and its gene” delivery “technology in mRNA and vector vaccines is well established, English said. “In a matter of months we hope to see the availability of new vaccines, tailored to the South African variant.”

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