But that does not mean that governments should dump their AstraZeneca stock. Experts believe that it is possible – and most likely – that the shot is still effective in preventing serious illness and death.
However, the news could be a major roadblock on the world’s path out of the pandemic, which could only end until the virus spreads widely.
The Oxford-AstraZeneca vaccine is cheaper and easier to transport and store than some of the other vaccines approved so far, and as such would play a key role in combating the pandemic in low- and middle-income countries. . If the vaccine is not effective enough against the new variant, it could deepen the already large vaccination gap between the world’s richest and poorest countries.
The study has not yet been peer-reviewed or fully published, so there are still many unknowns. What we do know is that it includes a relatively small number of volunteers who were predominantly young and healthy and therefore unlikely to suffer from severe Covid-19 disease. This meant that the study did not assess the protection against serious illness, hospitalization and death, and many experts suggested that it could still prevent the results.
“In the medium term, the prevention of more severe forms of Covid-19 is the most important; and it is suspected that the AstraZeneca vaccine will do so,” said Dr. Peter English, a consultant in control of communicable diseases, told the Science Media Center in the UK.
New vaccination strategy
Less effective vaccinations may force countries where the new variant becomes dominant to change their vaccination strategy.
Instead of trying to establish herd immunity, the focus may be on preventing as many deaths as possible, even while the virus continues to circulate.
Prof. Salim Abdool Karim, who is co-chair of the advisory committee of Covid-19 in South Africa, said the country is likely to take a more “drastic approach” in which they assess the impact of the vaccine as it is rolled out. out.
“We would start by vaccinating about 100,000 individuals in the first step. We will look at the hospitalization figures once we have done the vaccinations. And if we find that the hospitalization figures are below the threshold – which we are looking at – then we can be full be confident that the vaccine is effective … and if so, we can continue to continue the development, ‘he said.
“If we find that the hospitalizations are significant – more than we expected – then we will have to stop, take stock of where we are and maybe switch to other vaccines.”
But the AstraZeneca vaccine is an important part of the mass vaccination programs in many countries worldwide.
The COVAX program – a coalition that includes Gavi and the World Health Organization with the aim of distributing Covid-19 vaccines to poorer countries – is dependent 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 the Pfizer-BioNTech vaccine.
COVAX experts said on Monday that the WHO’s strategic advisory group of experts was finalizing new recommendations for the use of the AstraZeneca vaccine and submitting it to the Director – General on Tuesday.
South African health officials said they hoped 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 an agreement with Pfizer / BioNTech, but it is not clear when the doses will arrive.
Yet the AstraZeneca vaccine will at least initially be the most accessible option for many countries.
Relieving the burden on health services
The role of a vaccine is to teach the immune system to quickly detect and fight a virus. In essence, it helps the body remember an infection so that it acts faster when you become infected. “Your own immune system will also respond to clearing the virus, but without the vaccine, this response will be slower,” said Dr Julian Tang, honorary associate professor and clinical virologist at the University of Leicester.
The coronavirus vaccines currently available work by causing antibodies and T cells that are shown to fight the original coronavirus. Antibodies work by attaching and attacking the proteins on the surface of the virus – in the case of coronavirus it is the ear protein.
If the virus changes too much, especially in its protein, the antibodies caused by the vaccine may not bind very well to the new version of the virus, Tang explained.
“This means that these vaccine bodies cannot clear up as many of these viruses if you are infected. So there are even more viruses that you have to remove through your own immune response – which respond more slowly,” he adds.
“But studies suggest that there is enough binding of these vaccine antibodies to remove at least some of the different viruses from the system – to prevent serious illness and death.”
One of the main reasons why the pandemic was fatal was due to the large number of people in need of medical help, and a partially effective vaccine, although not ideal, would reduce this burden.
There were cases where healthcare systems could not enter the number of patients. If this happens, some patients may die because they cannot get help in time. There is also an effect on the whole system, with non-urgent treatments being postponed or canceled.
Experts argue that a vaccine would be beneficial if it could reduce the burden on health services.
“It may seem like fewer individuals who need an ICU bed and more individuals who can recover at home,” said Dr. Oliver Watson, a researcher on infectious diseases at Imperial College London, said. This can have significant consequences in the area where hospitals are located. very stretched. ‘
This was the case in many European countries, including the United Kingdom, where the government was forced to open several field hospitals to prevent the National Health System from being overwhelmed.
Adapting the vaccine
The data from South Africa is undoubtedly a setback for vaccination campaigns, but scientists are already working on updates to existing vaccines to make it more effective against new variants.
AstraZeneca said on Saturday it was working with the University of Oxford to adapt the vaccine against the B.1.351 variant and that it would promote it through clinical development to “prepare it for autumn delivery if needed”. ” Last month, Pfizer said it was “laying the groundwork” to create a vaccine enhancer that can respond to coronavirus variants.
“We see it all the time with the flu vaccine,” Tang said. Influenza vaccines are adapted each year to target the virus strains that circulate the most. Sometimes the vaccine chosen does not match the common strain.
“Several vaccine seasons do allow for more flu infections, illnesses and deaths – but to some extent this is inevitable, as the virus will always mutate first – then we will have to adapt our vaccines to suit the new virus,” Tang added. . .
British Health Secretary Matt Hancock said on Monday that the flu blueprint could work for the coronavirus in the future.
‘The jab is updated every year according to the mutations and variations that have occurred and noticed in the preceding few months, and which are produced during the summer and then transmitted into the arms of those most vulnerable to flu in the fall. , “he said.
As for Covid-19, he explained that we need to think about how we can protect people in the same way.
The good news is that developing a vaccine that will work against the new variants does not mean you have to start all over again, so updates may be available soon.
“The genome of the bile protein variety is well known, and the technology to fill the genes for it into mRNA and vector vaccines is well established,” Engels said. “We hope to see availability of new vaccines within months, adapted to the South African variant.”