But that does not mean that governments should throw away their AstraZeneca stocks. Experts say it is possible – and very likely – that the injection is still effective in preventing serious illness and death.
The news may, however, be a major obstacle to getting out of the pandemic world, which cannot “end” until the virus stops circulating widely.
The Oxford-AstraZeneca vaccine is cheaper and easier to transport and store than some of the other vaccines approved for use to date and, as such, would play a key role in fighting the pandemic in low and middle income countries. If the vaccine is not effective enough against the new variant, it could deepen the already huge vaccination gap between the world’s richest and poorest countries.
The study has not yet been peer reviewed or published in full, so many unknowns remain. What we do know is that it included a relatively small number of volunteers who were predominantly young and healthy and therefore probably did not suffer from severe Covid-19 disease. This means that the study did not evaluate protection against serious illness, hospitalization and death and many experts suggested that it could still prevent these results.
“In the medium term, what matters most is preventing more severe forms of Covid-19; and the AstraZeneca vaccine is believed to do this,” said Dr. Peter English, a consultant in communicable disease control, to the Science Media Center at UK.
New vaccination strategy
Less effective vaccines can force countries where new variants become dominant to change their vaccination strategy.
Instead of trying to get collective immunity, the focus may be on preventing as many deaths as possible, even while the virus continues to circulate.
Speaking to CNN, Professor Salim Abdool Karim, who is co-chairman of South Africa’s Covid-19 advisory committee, said the country is likely to take a “more gradual approach” in which to assess the impact of the vaccine as it goes. that it is thrown away.
“We would start vaccinating about 100,000 individuals in the first stage. We would see hospitalization rates after making these vaccinations. And if we find that hospitalization rates are below the threshold – which we are looking at – then we can be sure that the vaccine is effective. … and if it is, we can proceed with the deployment, “he said.
“If we find out that the hospitalizations are substantial – more than we anticipated – then we would have to stop, take stock of where we are and maybe switch to other vaccines.”
But the AstraZeneca vaccine is a key part of mass vaccination programs in many countries around the world.
The COVAX program – a coalition that includes Gavi and the World Health Organization with the aim of distributing Covid-19 vaccines to poorer countries – depends 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 are the Pfizer-BioNTech vaccine.
COVAX experts said on Monday that the WHO Strategic Advisory Group of Experts is finalizing new recommendations for the use of the AstraZeneca vaccine and will present them to the Director-General on Tuesday.
South African health officials said they expected 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 unclear when those doses will arrive.
Still, the AstraZeneca vaccine will, at least initially, be the most affordable option for many countries.
Relieving the burden on health services
The role of the vaccine is to teach the immune system to detect and fight a virus quickly. Essentially, it helps the body to remember an infection, so it acts faster if you get infected. “Your own immune system will also react to eliminate the virus, but without the vaccine, this reaction will be slower,” said Dr. Julian Tang, an honorary associate professor and clinical virologist at the University of Leicester.
Currently available coronavirus vaccines work by inducing antibodies and T cells that have been proven to fight the original coronavirus. Antibodies act by binding and attacking proteins on the virus surface – in the case of the coronavirus, it is the peak protein.
If the virus changes too much, especially in its peak protein, antibodies induced by the vaccine may not bind very well to the new version of the virus, explained Tang.
“This means that these antibodies in the vaccine cannot eliminate as much of these viruses when you are infected, so there are more viruses remaining that need to be eliminated by your own immune response – which reacts more slowly,” he added.
“But studies suggest that these antibodies are sufficiently linked to the vaccine to at least remove some of the variant viruses from the system – to prevent more serious illness and death.”
One of the main reasons why the pandemic was deadly is the large number of people who need medical attention, and a partially effective vaccine, while not ideal, would reduce that burden.
There have been cases where health systems have become unable to cope with the number of patients arriving. When this happens, some patients may die because they cannot get help in time. There is also a knock-on effect throughout the system, with non-urgent treatments postponed or canceled.
Experts argue that a vaccine will prove to be beneficial if it can reduce the burden on health services.
“It may seem that fewer individuals need an ICU bed and more individuals able to recover at home,” said Dr. Oliver Watson, an infectious disease researcher at Imperial College London, adding that this could have “real material consequences in environments where hospitals are 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 becoming overburdened.
Adjusting the vaccine
South Africa’s data is undoubtedly a setback for vaccination campaigns, but scientists are already working on updating existing vaccines to make them more effective against new variants.
AstraZeneca said on Saturday that it is working with the University of Oxford to adapt the vaccine against variant B.1.351 and that it will lead to clinical development to make it “ready for delivery in the fall, if necessary”. Last month, Pfizer said it was “laying the groundwork” to create a vaccine booster that could respond to coronavirus variants.
“We see this all the time with the flu shot,” said Tang. Influenza vaccines are adapted each year to target the strains of viruses that most circulate. Sometimes, the vaccine chosen does not correspond to the prevalent strain.
“Incompatible vaccine seasons allow for more influenza infections, morbidity and mortality – but to some extent this is inevitable, as the virus will always be mutated first – so we will have to adjust our vaccines to match the new virus,” added Tang . .
UK Health Secretary Matt Hancock said on Monday that the flu plan could work for the coronavirus in the future.
“The jab is updated every year according to the mutations and variations that happened and were detected in the previous months, and that it is manufactured during the summer, and then delivered into the arms of those who are most vulnerable to the flu in the fall,” he said.
When it comes to Covid-19, he explained that we need to think about how to protect people in a similar way.
The good news is that developing a vaccine that works against the new variants does not mean starting from scratch, so updates may be available soon.
“The genome of the spike protein variant is known, and the technology to” connect “the genes to it in mRNA and vector vaccines is well established,” said English. “In a few months, we hope to see the availability of new vaccines, adapted to the South African variant.”